Qian Gong, Yingying Yu, Lixing Kang et al.

Advanced Functional Materials • 2022

<jats:title>Abstract</jats:title><jats:p>The extraneural electrodes that cling to the nerve show great advantages in decreasing the damage of nerves, as compared to the intraneural electrodes. The grand challenge for the extraneural electrode is the instability of its electrode–nerve interface during nerve movement. In the proposed research, an adaptive, stretchable, and biocompatible carbonene extraneural electrode, which integrates rigid 2D defective graphene nanosheets on the soft carbon nanotube (CNT) fiber, is designed. The rigid nanosheets and the soft nanotubes are dominated by sp<jats:sup>2</jats:sup> nanocarbon, which is defined as carbonene. Benefiting from the soft and robust nature of the CNT fiber, the hybrid carbonene electrodes can be facile‐tailored into various complex shapes with a wide range of modulus (0.5–600 kPa), which plays a significant role in mechanical match of the modulus with that of the nerve. Moreover, the hybrid carbonene fiber exhibits excellent electrical conductivity (3.3 × 10<jats:sup>5</jats:sup> S m<jats:sup>−1</jats:sup>) and novel biocompatibility. As a result, the carbonene electrode shows a preferable performance compared to the traditional metal electrode, whose peak‐to‐peak action potential is 310% higher than the commercial Pt electrode. Overall, this work proposes a novel strategy for assembling the facile‐tailorable and biocompatible carbonene electrode, which can open an avenue for designing the next‐generation neural electrode.</jats:p>

Liang Wang, Suresh G. Advani, Ajay K. Prasad

ECS Meeting Abstracts • 2017

<jats:p> We have developed a self-healing membrane based on microcapsules prefilled with Nafion solution. The microcapsules are designed to rupture when they encounter defects formed in the membrane such as cracks and pinholes, and then release the prefilled Nafion solution to heal the defects in-situ. A procedure was developed to prepare microcapsules with a urea-formaldehyde shell prefilled with a Nafion/tributyl phosphate self-healing solution. The prepared microcapsules were characterized by SEM with focused ion beam (FIB) and optical microscopy. Proton conductivity, mechanical properties, swelling and water uptake of the composite membranes based on microcapsules were measured and compared with that of pure recast Nafion membranes. Fuel cell performance with 6 and 10 wt% microcapsules/Nafion membranes was compared with that of a pure recast Nafion membrane. Durability testing comprising 220 hours of OCV-hold with relative humidity cycling confirmed that the self-healing functionality could greatly extend the life span of the fuel cell membrane. </jats:p>

Giulia Massaglia, Marzia Quaglio

Nanomaterials • 0

<jats:p>Porous 3D composite materials are interesting anode electrodes for single chamber microbial fuel cells (SCMFCs) since they exploit a surface layer that is able to achieve the correct biocompatibility for the proliferation of electroactive bacteria and have an inner charge transfer element that favors electron transfer and improves the electrochemical activity of microorganisms. The crucial step is to fine-tune the continuous porosity inside the anode electrode, thus enhancing the bacterial growth, adhesion, and proliferation, and the substrate’s transport and waste products removal, avoiding pore clogging. To this purpose, a novel approach to synthetize a 3D composite aerogel is proposed in the present work. A 3D composite aerogel, based on polydimethylsiloxane (PDMS) and multi-wall carbon nanotubes (MWCNTs) as a conductive filler, was obtained by pouring this mixture over the commercial sugar, used as removable template to induce and tune the hierarchical continuous porosity into final nanostructures. In this scenario, the granularity of the sugar directly affects the porosities distribution inside the 3D composite aerogel, as confirmed by the morphological characterizations implemented. We demonstrated the capability to realize a high-performance bioelectrode, which showed a 3D porous structure characterized by a high surface area typical of aerogel materials, the required biocompatibility for bacterial proliferations, and an improved electron pathway inside it. Indeed, SCMFCs with 3D composite aerogel achieved current densities of (691.7 ± 9.5) mA m−2, three orders of magnitude higher than commercial carbon paper, (287.8 ± 16.1) mA m−2.</jats:p>

Livinus A. Obasi, Okechukwu D. Onukwuli, Chukwunonso C. Okoye

Current Research in Green and Sustainable Chemistry • 2021

S Muljani, A Wulanawati

ALCHEMY Jurnal Penelitian Kimia • 0

<jats:p>&lt;p&gt;Microbial fuel cell (MFC) represents a major bioelectrochemical system that converts biomass spontaneously into electricity through the activity of microorganisms. The MFC consists of anode and cathode compartments. Microorganisms in MFC liberate electrons while the electron donor is consumed. The produced electron is transmitted to the anode surface, but the generated protons must pass through the proton exchange membrane (PEM) to reach the cathode compartment. PEM, as a key factor, affects electricity generation in MFCs. The study attempted to investigate if the sulfonated polystyrene (SPS) membrane can be used as a PEM in the application on MFC. SPS membrane has been characterized using Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM) and conductivity.  The result of the conductivity (σ) revealed that the membrane has a promising application for MFC.&lt;/p&gt;</jats:p>

Narangarav Terbish, Srinivasa R. Popuri, Ching-Hwa Lee

Fuel • 2023

Ho-Young Jung, Sung-Hee Roh

Journal of Nanoscience and Nanotechnology • 2020

<jats:p>A microbial fuel cell (MFC) is bioelectrochemical system that enables the biochemical activities of bacteria to generate electricity. A composite membrane was prepared from polyvinylidene fluoride nanofiber coated with perfluorinated sulfuric acid ionomer (PVDF-PFSA) and evaluated as a replacement for the commercially available Nafion membrane, which is commonly used in MFC reactors. The power density obtained with the PVDF-PFSA composite membrane was higher than that obtained with the Nafion membrane in MFC reactors. The PVDF-PFSA composite membrane produced a maximum power density of 548 mW/m<jats:sup>2</jats:sup>. Hence, the PVDF-PFSA composite reported here is a promising candidate for use as a proton exchange membrane in energy devices and water treatment systems.</jats:p>

P. Kiatkittikul, T. Nohira, R. Hagiwara

Fuel Cells • 2015

<jats:title>Abstract</jats:title><jats:p>We have successfully prepared composite membranes consisting of the ionic liquid <jats:italic>N</jats:italic>‐ethyl‐<jats:italic>N</jats:italic>‐methylpyrrolidinium fluorohydrogenate and the polymer 2‐hydroxyethylmethacrylate and have secured them on a polyimide (PI) membrane support. The resulting EMPyr(FH)<jats:sub>1.7</jats:sub>F–HEMA (9:1 molar ratio) composite possesses ionic conductivity of 75 mS cm<jats:sup>−1</jats:sup> at 120 °C when a 16‐µm support is employed, showing improved performance with elevated temperature; this marks a significant difference from devices using conventional polytetrafluoroethylene supports. In the single cell test, a maximum power density of 31 mW cm<jats:sup>−2</jats:sup> is observed at 120 °C. Cross‐sectional SEM images of the corresponding membrane electrode assemblies reveal no significant difference in membrane thickness before and after cell testing, implying that this support does not suffer from membrane softening issues.</jats:p>

Barbara Mecheri, Valerio C.A. Ficca, Maida Aysla Costa de Oliveira et al.

ECS Meeting Abstracts • 2017

<jats:p> Microbial fuel cells (MFCs) can be considered as an efficient and flexible platform for integrated waste treatment and energy recovery [1]. The extensive research work devoted to this technology over the past decade demonstrates the promising outlook of MFCs, but practical application is still limited by the high costs associated to the materials used for device assembly, such as cathode materials which accounts for over 50% of the overall MFC capital cost. The sluggish kinetics of oxygen reduction reaction (ORR) has led to the use of expensive catalysts, such as platinum, which is not suitable to be applied to sustainable technologies. Hence, a great variety of materials have been developed for MFC cathodes, including nitrogen-doped activated carbons and non platinum group metal catalysts. Such materials allow achieving ORR rate comparable to Pt, the morphology and structure of the catalysts playing an important role on the efficiency and durability of ORR active sites [2,3]. The development of new carbon nanostructures with highly tunable morphology and structure has led to the use of graphene for several applications, including as component for MFC cathodes [4,5]. However, challenges, such as complexity in synthesis and costs, still limit the applicability of graphene as cathode component of MFCs. Therefore, a facile and efficient approach to develop graphene based catalysts can be considered a promising direction to achieve sustainable wastewater treatment and bioenergy production by BESs. </jats:p> <jats:p>In this work, we report a facile method for large-scale preparation of ORR catalysts based on graphene oxide (GO) obtained by electrochemical oxidation of graphite in aqueous solutions of inorganic salts. We developed different strategies to include nitrogen functionalities in GO structure, including post treatments based on annealing with ammonia gas and one-step nitrogen-doping of GO. By combining the use of atomic force microscopy with electrochemical and spectroscopic techniques, we correlated the different morphology and surface chemistry of GO with catalytic activity towards ORR. Differences in catalytic activity obtained by supporting iron on GO surface were also elucidated, investigating the nature of ORR active sites. The applicability of GO-based materials as ORR cathodes of MFCs was evaluated by assembling single chamber air-cathodes MFCs operating with sodium acetate in phosphate buffer solution. Coulombic efficiency, polarization and power density curves, and voltage generation cycles over time were acquired. The body of results demonstrated the potential ability of GO electrocatalysts to substitute platinum for ORR in MFCs. </jats:p> <jats:p> <jats:bold>Acknowledgements</jats:bold>. </jats:p> <jats:p>The present work was carried out with the support of the “European Union's Horizon 2020 research and innovation programme” (under H2020-FTIPilot-2015-1, Grant Agreement n. 720367-GREENERNET), the University of Rome Tor Vergata (under the Research Call “Consolidate the Foundations”, project name: BEST WATER), and CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil. </jats:p> <jats:p> <jats:bold>References.</jats:bold> </jats:p> <jats:p>[1] A. Rinaldi, B. Mecheri, V. Garavaglia, S. Licoccia, P. Di Nardo, E.Traversa. Energ. Environ. Sci., 1 (2008) 417-429. </jats:p> <jats:p>[2] C. Santoro, A. Serov, L. Stariha, M. Kodali, J. Gordon, S. Babanova, O. Bretschger, K. Artyushkova, P. Atanassov, Energ. Environ. Sci. 9 (2016) 2346-2353. </jats:p> <jats:p>[3] A. Iannaci, B. Mecheri, A. D'Epifanio, M. J. Lázaro Elorri, S. Licoccia. Int J Hydrogen Energ. 41 (2016) 19637-19644. </jats:p> <jats:p>[4] H. Yuan, Z. He. Nanoscale 7 (2015) 7022-7029. </jats:p> <jats:p>[5] K. Parvez, S. Yang, Y. Hernandez, A. Winter, A. Turchanin, X. Feng, K. Müllen. ACS Nano. 6 (2012) 9541-9550. </jats:p>

Nabin Aryal, Arnab Halder, Minwei Zhang et al.

Scientific Reports • 0

<jats:title>Abstract</jats:title><jats:p>During microbial electrosynthesis (MES) driven CO<jats:sub>2</jats:sub> reduction, cathode plays a vital role by donating electrons to microbe. Here, we exploited the advantage of reduced graphene oxide (RGO) paper as novel cathode material to enhance electron transfer between the cathode and microbe, which in turn facilitated CO<jats:sub>2</jats:sub> reduction. The acetate production rate of <jats:italic>Sporomusa ovata</jats:italic>-driven MES reactors was 168.5 ± 22.4 mmol m<jats:sup>−2</jats:sup> d<jats:sup>−1</jats:sup> with RGO paper cathodes poised at −690 mV versus standard hydrogen electrode. This rate was approximately 8 fold faster than for carbon paper electrodes of the same dimension. The current density with RGO paper cathodes of 2580 ± 540 mA m<jats:sup>−2</jats:sup> was increased 7 fold compared to carbon paper cathodes. This also corresponded to a better cathodic current response on their cyclic voltammetric curves. The coulombic efficiency for the electrons conversion into acetate was 90.7 ± 9.3% with RGO paper cathodes and 83.8 ± 4.2% with carbon paper cathodes, respectively. Furthermore, more intensive cell attachment was observed on RGO paper electrodes than on carbon paper electrodes with confocal laser scanning microscopy and scanning electron microscopy. These results highlight the potential of RGO paper as a promising cathode for MES from CO<jats:sub>2</jats:sub>.</jats:p>

Vlad I Redko, Elena M Shembel, Volodymyr S Khandetskyy et al.

ECS Meeting Abstracts • 2016

<jats:p>Proprietary non-destructive non-contact (NDT) electromagnetic, holographic interferometry, gas discharge visualization, and combined methods, developed by Enerize, enable to evaluate properties of nano-structured powder of electrode materials, polymer and solid inorganic electrolytes, and interface of multi-layered electrode structures. Developed non-destructive testing methods &amp; devices enable to optimize the technology, and quality of initial materials, components, and cells, including in-line control during battery production. These methods allow insure the safety and reliability of the batteries and reduce the cost of production </jats:p> <jats:p>Electromagnetic NDT inspection consists in estimation of the level of magnetic fields interaction between the primary and secondary transducers from the currents induced by the primary field in investigated object. </jats:p> <jats:p>Primary transducer creates magnetic field at alternating current passage on it. This magnetic field excites eddy currents in investigated object. Eddy currents create secondary magnetic field, which is directed towards the primary one, and the total field is less by the value of the secondary field. The value of secondary field depends on the value of induced primary eddy currents, and their value directly depends on the quality and controlled object properties. Thus, one can judge about controlled object quality by the value of summary magnetic field. </jats:p> <jats:p>Using these methods we can control without contact the following values: conductivity, defect availability, dielectric permeability, thickness and solve many other problems of non-destructive testing. </jats:p> <jats:p>The non-contact feature of these methods allows in-line quality control during synthesis of component materials as well as during production and final assembly of batteries, supercapacitors, solar cells, etc. Application of these systems results in improved product reliability and safety, while lowering overall manufacturing costs by reducing wastage and preventing defective components from being incorporated into the finished product. </jats:p> <jats:p>A number of mathematical tools are used for process description and modeling, for signal processing, and for generating properties control information based on analysis the dependences between the parameters the fields that are applied and the electro-physical characteristics the test article that measured. These include: mathematical descriptions of elastic waves in isotropic and anisotropic media; Maxwell’s and Laplace’s equations; mathematical tools for spectral transformations in different orthogonal bases; methods of defect identification and the processing and analysis of images using fuzzy logic and artificial neural networks.</jats:p> <jats:p>During presentation will be presented NDT methods and systems developed by Enerize for the following electromagnetic testing: determine specific conductivity, electromagnetic properties and composition of powdered materials, including nano powdered oxides and graphite for Li-ion batteries electrodes ; specific conductivity of thin films (transparent conductive oxides for solar cells, solid and polymer electrolytes, polymer membranes for fuel cells, etc.); non-contact electromagnetic testing to determine the interface resistance between current collector and active electrode mass; nondestructive determination of defects in multilayer structures based on combined ultrasonic and electromagnetic methods (e.g., “jelly-rolls” for batteries and supercapacitors) and other. </jats:p> <jats:p>The developed methods and equipment can be adapted from measurements of test articles or materials under static conditions to dynamic measurements during material synthesis. </jats:p> <jats:p> <jats:italic>Enerize owns </jats:italic>14 US patents, 1 Great Britain patent, and numerous US patent applications in the area of Li-ion batteries, solar cells, and non-destructive non-contact testing..</jats:p>

Zhongwei Chen

ECS Meeting Abstracts • 2019

<jats:p> Advanced battery technology plays key roles in pursuit of sustainable energy future by electrifying the transportation fleet and converting/storing the intermittent green energy source in grid scale. Among the candidates, lithium-sulfur (Li-S) battery has risen up as a particularly promising successor to the currently dominating lithium-ion batteries due to its intriguingly high energy density and cost effectiveness. However, the practical implementation of Li-S battery can be achievable only when several critical problems are well addressed, which involve the insulting nature of cathode materials, the unruly polysulfide shuttling behavior, low efficiency of metallic lithium redox reactions, etc. These bugbears have been haunting the Li-S system and obstructing its access to practically high capacity and long lifespan. </jats:p> <jats:p>Targeting at these problems, we have long been committed to pursuing high-efficiency Li-S electrochemistry with extensive research interests in multiple battery ingredients. Following the two strategic emphasis on conduction properties and sulfur confinement, a series of functional host materials with delicate nano-/micro-structures has been successfully developed to fulfill fast and durable sulfur electrochemistry, which enables high sulfur loading and minimum electrolyte with achievable energy density that meets the commercial benchmark. Beyond that, targeted surface functionalization has been dedicated on separator to regulate the diffusion behavior of polysulfide, while host strategy with rationally-designed architecture has been also employed in lithium anode to suppress the dendrite formation and enhance the redox reversibility. Through the multi-sectional improvements, we are aiming at the establishment of an interoperable mechanism at a system level to promote the fundamental understanding as well as the practical electrochemical performance of Li-S battery for future commercialization. </jats:p>

Jingjie Wu, Tianyu Zhang

ECS Meeting Abstracts • 2019

<jats:p> Electrocatalytic reduction of CO<jats:sub>2</jats:sub> into value added chemicals or fuels is a promising technique towards a carbon-neutral chemical process. The electrochemical reduction of CO<jats:sub>2</jats:sub> is a complicated process involving multiple protons coupled electron transfer, theoretically resulting in a variety of products (e.g. CO, HCOOH, CH<jats:sub>4</jats:sub>, C<jats:sub>2</jats:sub>H<jats:sub>4</jats:sub> and C<jats:sub>2</jats:sub>H<jats:sub>5</jats:sub>OH). Therefore, the major challenge in CO<jats:sub>2</jats:sub> reduction lies in the manipulation of the selectivity towards a specific product as demanded. However, the study on CO<jats:sub>2</jats:sub> reduction has not substantially advanced primarily because of the lack of fundamental understanding of the reaction mechanism and the challenge of discovering efficient and robust catalysts for the various multi-electron transfer processes. Researchers have screened a wide range of metal-based materials for electrochemical reduction of CO<jats:sub>2</jats:sub>, and found only copper-based metals exhibit selectivity towards formation of hydrocarbons and oxygenates at fairly high efficiencies while most others favor production of carbon monoxide or formate. </jats:p> <jats:p>Here we present the development of carbon materials as an alternative to Cu for efficient and high-rate electro-reduction of CO<jats:sub>2</jats:sub> into hydrocarbons and oxygenates. We will discuss the key structural and electronic factors that govern the selectivity of carbon catalysts towards production of CO, CH<jats:sub>4</jats:sub> and C<jats:sub>2</jats:sub> products (e.g. C<jats:sub>2</jats:sub>H<jats:sub>4</jats:sub> and C<jats:sub>2</jats:sub>H<jats:sub>5</jats:sub>OH). Three categories of carbon catalysts were developed based on the primary products of CO, CH<jats:sub>4</jats:sub> and C<jats:sub>2</jats:sub>H<jats:sub>4</jats:sub> in our group. The first carbon catalyst featuring the metal-nitrogen-carbon structure exclusively catalyzes CO<jats:sub>2</jats:sub> electro-reduction into CO. The second catalyst called functionalized carbon nanostructure can selectively reduce CO<jats:sub>2 </jats:sub>into CH<jats:sub>4</jats:sub> with Faradaic efficiency up to 90% while the third one namely doped carbon nanostructure (e.g. N-doped graphene quantum dots) can yield C<jats:sub>≥2</jats:sub> products with a Faradaic efficiency up to 70%. Both carbon nanostructure can achieve partial current density at the scale of 100 mA cm<jats:sup>-2</jats:sup> for target product at fairly low overpotentials. This study provides in-depth insights into developing high-performance carbon-based catalysts for electrochemical reduction of CO<jats:sub>2</jats:sub>. </jats:p>

Aya Mohamed, Peter Bogdanoff

ECS Meeting Abstracts • 2023

<jats:p> Solar powered electrochemical CO₂ reduction to disposable products is presently being developed as one of negative carbon emission technologies<jats:sup>1</jats:sup>. State-of-the-art electrocatalysts are mainly developed for the CO<jats:sub>2</jats:sub> reduction to hydrogen rich products or chemical feedstock materials while for the above-mentioned application solid carbon-rich products are desired (best pure carbon). Even though the formation of solid products is sometimes observed on catalysts (coking effect), this usually leads to an undesirable irreversible deactivation of their solid interfaces.</jats:p> <jats:p>Thus, the development of next generation CO<jats:sub>2</jats:sub> electrocatalysts is demanded based on liquid metal alloys such as galinstan (GaInSn). The advantage of using liquid phase electrodes is to eliminate coking and coarsening limitations that are associated with solid catalysts. For example, it has been reported that ceria-supported liquid galinstan can electrochemically produce carbonaceous materials from CO<jats:sub>2</jats:sub> gas<jats:sup>2</jats:sup>. This shows, that doping with additional active elements can change the CO<jats:sub>2</jats:sub> reduction activity of GaInSn in the direction of other desired products.</jats:p> <jats:p>Our work investigates the activity of galinstan for the electroreduction of CO<jats:sub>2</jats:sub> depending on alloying with additional metals (such as Ce, Ag, Pb). While pure GaInSn shows a predominant activity for the formation of C1 products (CO, HCOOH) in DMF/H<jats:sub>2</jats:sub>O electrolyte, we are mainly interested in the formation of solid carbon or oxalate. Therefore, our investigations aim at finding suitable modifications of GaInSn that achieve high selectivity for these products. Electrochemical analysis coupled with in-line gas chromatography and in-line mass spectroscopy are used to characterize the reactivity. Furthermore, the influence of the water content of the organic electrolyte on the product selectivity will be investigated. In particular, to suppress the observed low hydrogen evolution as a by-product even more efficiently.</jats:p> <jats:p> <jats:list list-type="roman-lower"> <jats:list-item> <jats:p>May, M. M.; Rehfeld, K., Negative Emissions as the New Frontier of Photoelectrochemical CO<jats:sub>2</jats:sub> Reduction. <jats:italic>Advanced Energy Materials </jats:italic> <jats:bold>2022,</jats:bold> 2103801.</jats:p> </jats:list-item> <jats:list-item> <jats:p>Esrafilzadeh, D.; Zavabeti, A.; Jalili, R.; Atkin, P.; Choi, J.; Carey, B. J.; Brkljača, R.; O’Mullane, A. P.; Dickey, M. D.; Officer, D. L.; MacFarlane, D. R.; Daeneke, T.; Kalantar-Zadeh, K., Room Temperature CO<jats:sub>2</jats:sub> Reduction to Solid Carbon Species on Liquid Metals Featuring Atomically Thin Ceria Interfaces. <jats:italic>Nature Communications </jats:italic> <jats:bold>2019,</jats:bold> <jats:italic>10</jats:italic> (1), 865.</jats:p> </jats:list-item> </jats:list> </jats:p> <jats:p> <jats:inline-formula> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2400fig1.jpg" xlink:type="simple"/> </jats:inline-formula> </jats:p> <jats:p>Figure 1</jats:p> <jats:p/>

Shelley D. Minteer

ECS Meeting Abstracts • 2020

<jats:p> CO<jats:sub>2</jats:sub> reduction has the potential to address issues related to the environment and the energy crisis. However, the reduction of CO<jats:sub>2</jats:sub> is hard to achieve due to its kinetic and thermodynamic stability. Despite significant research effort, existing catalysts such as transition metals and metal complex suffer from either low selectivity and/or low CO<jats:sub>2</jats:sub> conversion efficiency. Biocatalysts are an attractive alternative owing to their highly selectivity, low overpotential and mild operating conditions. A recently developed molybdenum dependent formate dehydrogenase (Mo-FDH) from <jats:italic>Escherichia coli</jats:italic> is a biocatalyst that is easy to obtain and has high efficiency to interconvert formate and CO<jats:sub>2</jats:sub>. However, the direct electron transfer of Mo-FDH is inefficient, and so far, no immobilized mediating system has been designed with Mo-FDH to support CO<jats:sub>2</jats:sub> reduction. Low potential redox polymers are rare due to a limited number of mediators and stability issues. Here we developed a reductive redox polymer (cobaltocene modified poly allyl amine; Cc-PAA) to wire Mo-FDH at carbon electrode surfaces and simultaneously mediate electrons to facilitate the CO<jats:sub>2</jats:sub> reduction. The polymer film shows good stability and formate was the exclusive product. This electroenzymatic interface is able to reduce CO<jats:sub>2</jats:sub> to formate at a mild applied potential (-0.66 V. <jats:italic>vs</jats:italic> SHE) with a high Faradaic efficiency (99 ± 5%). </jats:p>

Toshihiro Takashima, Tomohiro Suzuki, Hiroshi Irie

ECS Meeting Abstracts • 2016

<jats:p>The utilization of carbon dioxide (CO<jats:sub>2</jats:sub>) for the production of fuels and valuable chemicals has gained increasing attention as a strategy for solving both global energy and environmental issues.[1] Among the various proposed methods, the electrochemical reduction of CO<jats:sub>2</jats:sub> using electricity powered by renewable resources is attractive, and numerous electrode materials capable of converting CO<jats:sub>2</jats:sub> to carbon monoxide (CO), formate, methanol, methane, and other hydrocarbons have been identified in the past few decades. However, there still remain several fundamental challenges in the electrocatalytic reduction of CO<jats:sub>2</jats:sub>, such as high overpotential and low Faradaic efficiency due to the competitive hydrogen evolution reaction. Recently, it was reported that a palladium (Pd) nanoparticle electrode can reduce CO<jats:sub>2</jats:sub> to formate with high energy efficiency (with low overpotential) [1]. However, the electrode was also reported to be deactivated by adsorption of CO which is produced as a byproduct. In this study, to suppress the deactivation by CO, we focused on a Pd nanoparticle electrode modified covered with copper (Cu) because the binding energy of CO on Cu was reported to be weaker than that on Pd [3]. In addition, it is known that Cu monolayer can be formed on Pd support by using underpotential deposition (UPD) [4]. Thus, we prepared a Pd nanoparticle electrode covered with Cu monolayer (Cu/Pd electrode) and examined its CO<jats:sub>2</jats:sub>reduction activity and tolerance to CO. </jats:p> <jats:p>A Pd nanoparticle electrode was prepared by loading homogeneous catalyst ink onto a fluorine-doped tin oxide (FTO) electrode. The ink was composed of a mixture of Pd-supporting carbon black powder, Nafion, and isopropanol. The Pd-supporting carbon black powder was purchased from Premetek. UPD of Cu was carried out by holding the electrode potential at 0.35 V vs. reversible hydrogen electrode (RHE) for 50 s in a mixed solution of 50 mM sulfuric acid (H<jats:sub>2</jats:sub>SO<jats:sub>4</jats:sub>) and 50 mM copper sulfate (CuSO<jats:sub>4</jats:sub>). Electrolyses were performed in a gas-tight two-compartment electrochemical cell with a piece of anion exchange membrane as the separator. An aqueous solution of 0.5 M sodium hydrogen carbonate (NaHCO<jats:sub>3</jats:sub>) saturated with CO<jats:sub>2</jats:sub>was used as an electrolyte. </jats:p> <jats:p>Figure 1 shows chronoamperograms for CO<jats:sub>2</jats:sub> reduction of Pd and Cu/Pd electrodes measured at -0.15 V vs RHE. In the initial stage, the current density of a Cu/Pd electrode was smaller than that of a Pd electrode. This is plausible because the surface area of Pd exposed to the electrolyte decreased by deposition of Cu. However, the Cu/Pd electrode was active for CO<jats:sub>2</jats:sub> reduction even after deposition of Cu and production of formate was confirmed by analysis of the electrolyte using gas chromatograph (GC). Notably, the reduction current of the Cu/Pd electrode maintained more steadily than that of the Pd electrode during long-term electrolysis, suggesting that the electrodeposited Cu monolayer improved the tolerance to CO. To examine the effect of Cu layer on CO adsorption, CO<jats:sub>2</jats:sub> reduction activity in the presence of CO was also investigate. When CO was introduced into the electrolyte by bubbling, the current density of both Pd and Cu/Pd electrodes decreased, however the degree of deactivation of the Cu/Pd electrode was less than that of the Pd electrode. These results indicate that the covering of Pd nanoparticle with Cu monolayer improves its tolerance to CO without losing CO<jats:sub>2</jats:sub>reduction activity. </jats:p> <jats:p>References </jats:p> <jats:p>[1] M. Aresta, A. Dibenedetto, A. Angelini, <jats:italic>Chem. Rev.</jats:italic>, <jats:bold>2014</jats:bold>, <jats:italic>114</jats:italic>, 1709-1742. </jats:p> <jats:p>[2] X. Min and M. W. Kanan, <jats:italic>J. Am. Chem. Soc.</jats:italic>, <jats:bold>2015</jats:bold>, <jats:italic>137</jats:italic>, 4701-4708. </jats:p> <jats:p>[3] A. A. Peterson and J. K. Nørskov, <jats:italic>J. Phys. Chem. Lett.</jats:italic>, <jats:bold>2012</jats:bold>, <jats:italic>3</jats:italic>, 251-258. </jats:p> <jats:p>[4] T. Chierchie and C. Mayer, <jats:italic>Electrochim. Acta</jats:italic>, <jats:bold>1988</jats:bold>, <jats:italic>33</jats:italic>, 341-345.</jats:p> <jats:p/> <jats:p> <jats:inline-formula> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="3031fig1.jpeg" xlink:type="simple"/> </jats:inline-formula> </jats:p> <jats:p>Figure 1</jats:p> <jats:p/>

Zhanxi Fan

Energy Lab • 0

<jats:p>Electrochemical carbon dioxide (CO2) reduction is emerging as a promising technique to decrease atmospheric CO2 concentration and relieve energy pressure. Besides the single-carbon (C1) species, multi-carbon (C2+) products are more preferred because of their elevated energy density and/or larger economic value. Single atom catalysts (SACs) have been widely used in the field of catalysis due to their tunable active center and unique electronic structure. So far, extensive research progresses have been achieved in utilizing SACs to promote the CO2 reduction toward C1 products, but little attention is paid to the formation of high-value C2+ products. In this review, we present the recent advances of electrochemical reduction of CO2 to C2+ products with SACs. Firstly, the reaction mechanism of converting CO2 to C2+ products is briefly introduced. Then the general design principles of SACs toward C2+ products are systematically discussed. After that, we highlight the representative studies on the C2+ generation and the corresponding mechanism with SACs, including the copper and non-copper based SACs. Finally, we summarize the latest progresses and provide personal perspectives for the future design and target preparation of advanced SACs for the high-performance CO2 electrolysis to specific C2+ products.</jats:p>

Joana Madjarov, Ricardo Soares, Catarina M. Paquete et al.

Frontiers in Microbiology • 0

<jats:p><jats:italic>Sporomusa ovata</jats:italic> is a bacterium that can accept electrons from cathodes to drive microbial electrosynthesis (MES) of acetate from carbon dioxide. It is the biocatalyst with the highest acetate production rate described. Here we review the research on <jats:italic>S. ovata</jats:italic> across different disciplines, including microbiology, biochemistry, engineering, and materials science, to summarize and assess the state-of-the-art. The improvement of the biocatalytic capacity of <jats:italic>S. ovata</jats:italic> in the last 10 years, using different optimization strategies is described and discussed. In addition, we propose possible electron uptake routes derived from genetic and experimental data described in the literature and point out the possibilities to understand and improve the performance of <jats:italic>S. ovata</jats:italic> through genetic engineering. Finally, we identify current knowledge gaps guiding further research efforts to explore this promising organism for the MES field.</jats:p>

Vafa Ahmadi, Nabin Aryal

Fermentation • 0

<jats:p>Optimal product synthesis in bioelectrochemical systems (BESs) requires a comprehensive understanding of the relationship between external voltage and microbial yield. While most studies assume constant growth yields or rely on empirical estimates, this study presents a novel thermodynamic model, linking anodic oxidation and cathodic carbon dioxide (CO2) reduction to methane (CH4) by growing microbial biofilm. Through integrating theoretical Gibbs free energy calculations, the model predicts electron and proton transfers for autotrophic methanogen and anode-respiring bacteria (ARB) growth, accounting for varying applied voltages and substrate concentrations. The findings identify an optimal applied cathodic potential of −0.3 V vs. the standard hydrogen electrode (SHE) for maximizing CH4 production under standard conditions (pH 7, 25 °C, 1 atm) regardless of ohmic losses. The model bridges the stoichiometry of anodic and cathodic biofilms, addressing research gaps in simulating anodic and cathodic biofilm growth simultaneously. Additionally, sensitivity analyses reveal that lower substrate concentrations require more negative voltages than standard condition to stimulate microbial growth. The model was validated using experimental data, demonstrating reasonable predictions of biomass growth and CH4 yield under different operating voltages in a multi substrate system. The results show that higher voltage inputs increase biomass yield while reducing CH4 output due to non-optimal voltage. This validated model provides a tool for optimizing BES performance to enhance CH4 recovery and biofilm stability. These insights contribute to finding optimum voltage for the highest CH4 production for energy efficient CO2 reduction for scaling up BES technology.</jats:p>

Tambakassi Mihin, Boris Tartakovsky, Oumarou Savadogo

ECS Meeting Abstracts • 2025

<jats:p> <jats:bold>Introduction:</jats:bold> Climate change, due to the release of greenhouse gases such as carbon dioxide (CO<jats:sub>2</jats:sub>),<jats:sub> </jats:sub>is a global environmental issue. An effective energy transition relies on the substantial utilization of renewable energy sources and the development of CO<jats:sub>2</jats:sub> reduction products, such as e-fuels and e-chemicals. In particular, the potential for large-scale CO<jats:sub>2</jats:sub> reduction could contribute significantly to mitigating the greenhouse effect. Accordingly, promising CO<jats:sub>2</jats:sub> recycling approaches include<jats:sub> </jats:sub>electrochemical as well as bio-electrochemical methods. Currently, both methods for CO<jats:sub>2</jats:sub> reduction are limited by relatively low selectivity, high cost and low material stability, particularly with respect to cathode materials (Farooqi et al., 2023; Zhang et al., 2021).</jats:p> <jats:p>The approach presented in this study proposes using cathode materials based on synthesized non-noble bimetallic oxides for electrochemical and bioelectrochemical reduction of CO<jats:sub>2</jats:sub>. This is the first time a comparison of electrochemical and bioelectrochemical reduction of CO<jats:sub>2</jats:sub> is carried out.</jats:p> <jats:p> <jats:bold>Experimental: </jats:bold>Bimetallic oxides FeCuO, MnCuO, and SnCuO, CoMnO and FeSnO were synthesized using sol-gel methods in three molar ratios (1/2, 1/1, and 2/1) and characterized by XRD and EDS methods. The electrocatalyst was fabricated by mixing their powder with Nafion solution to obtain a paste, which is deposited on carbon felt. CO<jats:sub>2</jats:sub> reduction was performed in an electrolytic cell (EC) and a microbial electrosynthesis (MES) cell using sodium bicarbonate solution (pH 6.5, 0.5M) and enriched mixed acidogenic culture at pH 6.0, respectively. Batch activity tests were first carried out to evaluate the bimetallic oxides’ performances on CO<jats:sub>2</jats:sub> reduction by methanogenic and acidogenic microorganisms using serological bottles containing microbial cultures capable of reducing CO<jats:sub>2</jats:sub> and hydrogen to methane (CH<jats:sub>4</jats:sub>) and volatile fatty acids (VFAs). The bimetallic oxides were used either in powder form at concentrations of 1–2.5 g/L or deposited on carbon felt at an active loading of 10 mg cm<jats:sup>-2</jats:sup>. Among the five bimetallic oxides tested, three promising candidates were selecte. Stability tests were conducted with these oxides at three molar ratios at a current density of 156 A m<jats:sup>-2</jats:sup> for 20 hours in an electrolytic cell. Electrochemical CO<jats:sub>2</jats:sub> reduction was subsequently performed using the most stable oxides across various current densities (13–100 A m<jats:sup>-2</jats:sup>) under standard conditions, and Coulombic efficiency (CE) was calculated. Additionally, bioelectrochemical reduction tests were conducted at 3, 5, and 8 A m<jats:sup>-2</jats:sup> in a MES cell, inoculated with enriched mixed acetogenic culture (table 1). Both uncoated carbon felt, and carbon felt coated with FeSnO (1/1) were used as cathode materials. Analysis of gases and VFAs was performed using gas chromatography, while liquid chromatography was employed for alcohol analysis.</jats:p> <jats:p> <jats:bold>Preliminary Results: </jats:bold>The crystalline structure and the stoichiometric composition of the bimetallic oxides were confirmed, respectively by XRD and EDS characterization of annealed samples. Based on Cyclic Voltammetry, current-voltage polarization and Tafel plot curves, the electrolytic currents of the CO<jats:sub>2 </jats:sub>electro-reduction were identified. Table 2 shows the CE of the electro-reduction of CO<jats:sub>2</jats:sub> to methanol and tert-butanol for various current density on the best bimetallic oxides FeCuO (2/1), CoMnO (2/1) and FeSnO (1/1), respectively. For these electrodes, the CE of the water electrolysis to hydrogen is, of course, significantly higher (at least 75%) than those of the electro-reduction of CO<jats:sub>2</jats:sub>. The CE of the CO<jats:sub>2</jats:sub> electro-reduction is less than 20%. The CE of the CO<jats:sub>2</jats:sub> electro-reduction to methanol is lower than that of its electrochemical reduction to tert-butanol. The highest CE of the CO<jats:sub>2</jats:sub> electro-reduction to e-fuels and e-chemicals is obtained on the FeCuO electrocatalyst. The optimum current density for CO<jats:sub>2</jats:sub> electro-reduction is in the range of 30-75 A m<jats:sup>-2</jats:sup>. Table 3 shows the results of the bioelectrochemical reduction of CO<jats:sub>2</jats:sub> in MES cell using FeSnO (1/1) electrode. Calculated CE ranged from 60% to 88% at various current densities. The CE of CO₂ reduction to VFAs ranged from 53% to 79%, with a CO₂ conversion efficiency reaching 96% under continuous operation with CO₂ flow rates of 200 and 300 mL/day to the cathode compartment. Production of butyrate and caproate increased by 4.6 and 3.9 times, respectively, in the MES cell with the FeSnO (1/1) cathode compared to a MES cell with an uncoated carbon felt cathode.</jats:p> <jats:p> <jats:bold>Conclusion:</jats:bold> The study shows that selecting specific bimetallic oxides can influence microbial CO<jats:sub>2</jats:sub> reduction. Furthermore, converting an electrochemical cell to a microbial electrosynthesis cell by adding an enriched mixed acidogenic culture in the cathode compartment enhances CO<jats:sub>2</jats:sub> reduction. The findings also indicate that the microbial chain elongation activity of the mixed culture improves with the presence of certain bimetallic oxides, such as FeSnO.</jats:p> <jats:p> <jats:inline-formula> </jats:inline-formula> </jats:p> <jats:p>Figure 1</jats:p> <jats:p/>

Jayachitra Murugaiyan, Anantharaman Narayanan, Samsudeen Naina Mohamed

Water Environment Research • 2024

<jats:title>Abstract</jats:title><jats:sec><jats:label/><jats:p>Microbial electrolysis cell (MEC) is gaining importance not only for effectively treating wastewater but also for producing hydrogen. The up‐flow microbial electrolysis cell (UPMEC) is an innovative approach to enhance the efficiency, and substrate degradation. In this study, a baffled UPMEC with an anode divided into three regions by inserting the baffle (sieve) plates at varying distances from the cathode was designed. The effect of process parameters, such as flow rate (10, 15, and 20 mL/min), electrode area (50, 100, and 150 cm<jats:sup>2</jats:sup>), and catholyte buffer concentration (50, 100, and 150 mM) were investigated using distillery wastewater as substrate. The experimental results showed a maximum of 0.6837 ± 0.02 mmol/L biohydrogen at 150 mM buffer, with 49 ± 1.0% COD reduction using an electrode of area 150 cm<jats:sup>2</jats:sup>. The maximum current density was 1335.94 mA/m<jats:sup>2</jats:sup> for the flow rate of 15 mL/min and surface area of 150 cm<jats:sup>2</jats:sup>. The results showed that at optimized flow rate and buffer concentration, maximum hydrogen production and effective treatment of wastewater were achieved in the baffled UPMEC.</jats:p></jats:sec><jats:sec><jats:title>Practitioner Points</jats:title><jats:p><jats:list list-type="bullet"> <jats:list-item><jats:p>Biohydrogen production from distillery wastewater was investigated in a baffled UPMEC.</jats:p></jats:list-item> <jats:list-item><jats:p>Flowrate, concentration and electrode areas significantly influenced the hydrogen production.</jats:p></jats:list-item> <jats:list-item><jats:p>Maximum hydrogen (0.6837±0.02mmol/L.day) production and COD reduction (49±1.0%) was achieved at 15 mL/min.</jats:p></jats:list-item> <jats:list-item><jats:p>Highest CHR of 95.37±1.9 % and OHR of 4.6±0.09 % was observed at 150 mM buffer concentration.</jats:p></jats:list-item> </jats:list></jats:p></jats:sec>

Tamilmani Jayabalan, Samsudeen Naina Mohamed, Manickam Matheswaran et al.

International Journal of Energy Research • 2021

<jats:title>Summary</jats:title><jats:p>Development of economically viable cathode catalysts with practicability in the treatment of real effluents is one of the strenuous efforts among the multidisciplinary approaches in microbial electrolysis cell (MEC). Treatment of industrial effluents using this technology had resulted in simultaneous energy production in the form of hydrogen along with wastewater treatment, promoting both energy and environmental benefits. In this study, two metal oxides such as, Nickel Oxide (NiO) and Cobalt oxide (Co<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub>) were employed as the cathode catalyst using sugar industry effluent as the substrate for biohydrogen production in the MEC. The addition of NiO and Co<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub> on nickel foam (NF) has demonstrated better hydrogen evolution performance than the control (uncoated) cathode. Electrochemical characterization of the modified cathodes revealed the improved capability analogous to the current density and hydrogen production rate (HPR) obtained in the experimentation. The best performance was achieved by NiO/NF with the maximum HPR of 3.39 ± 0.03 mmol/L/D, coloumbic efficiency of 58 ± 1.4%, hydrogen recovery of 27 ± 1.8% and COD removal efficiency of 52 ± 1.6% when operated with the applied voltage of 1.0 V. Hence, the potential of metal oxides was demonstrated for the candidature of efficient and economical cathode materials in MECs.</jats:p>

Putty Ekadewi, Rita Arbianti, Cristina Gomez et al.

Food Technology and Biotechnology • 2023

<jats:p>Research background. This study provides insight into the use of a designed microbial community to produce biohydrogen in simple, single-chamber microbial electrolysis cells (MECs). The ability of MECs to stably produce biohydrogen relies heavily on the setup and microorganisms working inside the system. Despite having the most straightforward configuration and effectively avoiding costly membranes, single-chamber MECs are prone to competing metabolic pathways. We present in this study one possible way of avoiding this problem using characteristically defined, designed microbial consortium. Here, we compare the performance of MECs inoculated with a designed consortium to MECs operating with a naturally occurring soil consortium. Experimental approach. We adapted a cost-effective and simple single-chamber MEC design. The MEC was gastight, 100 mL in volume, and equipped with continuous monitoring for electrical output using a digital multimeter. Microorganisms were sourced from Indonesian environmental samples, either as denitrifying bacterial isolates grouped as a designed consortium or natural soil microbiome used in its entirety. The designed consortium consisted of five species from the Pseudomonas and Acinetobacter genera. The headspace gas profile was monitored periodically with a gas chromatograph. At the end of the culture, the composition of the natural soil consortium was characterized by next generation sequencing and the growth of the bacteria on the surface of the anodes by field emission scanning electron microscopy. Results and conclusions. We found that MEC using a designed consortium presented a better H2 production profile, with the ability of the system to maintain headspace H2 concentration relatively stable for a long time after reaching stationary growth period. In contrast, MECs inoculated with soil microbiome exhibited a strong decline in headspace H2 profile within the same time frame. Novelty and scientific contribution. This work utilizes a designed, denitrifying bacterial consortium isolated from Indonesian environmental samples that can survive in a nitrate-rich environment. Here we propose using a designed consortium as a biological approach to avoid methanogenesis in MECs, as a simple and environmentally friendly alternative to current chemical/physical methods. Our findings offer an alternative solution to avoid the problem of H2 loss in single-chamber MECs along with optimizing biohydrogen production through bioelectrochemical routes.</jats:p>

Matthew Hardhi, Putty Ekadewi, Rita Arbianti et al.

E3S Web of Conferences • 2018

<jats:p>The increasingly adverse effects of climate change caused by a variety of fossil-based fuel demands an alternative to such fuel. Hydrogen is one of the potential renewable fuel that offers numerous advantages compared to its competitors. However, the dominant hydrogen production methods are still energy-heavy and dependent on fossil-based resources. Microbial electrolysis cell or MEC system is one of the leading solution towards replacing conventional hydrogen production method. A persistent downside to this system in the presence of methanogens that consumes the hydrogen product. This research proposes alternative biological method to control the methanogen colony by introducing isolates of denitrifying bacteria to the system which will act as inhibitor to hydrogenotrophic methanogen. The reactor implemented is a single-chambered, membrane-less 20-ml reactor. Net hydrogen yield produced in the cathodic headspace will be analyzed by gas chromatography (GC). Hydrogen yield for reactor with enriched cathode is expected to be higher in comparison to unenriched reactor, as nitrogen oxides produced during the metabolism of the denitrifiers were known to inhibit methanogen growth. Experimental results showed consistent higher H<jats:sup>2</jats:sup> yield in inoculated reactor compared to control reactor, where in the second cycle H<jats:sup>2</jats:sup> production increased 100% compared to the control.</jats:p>

Pooja Dange, Soumya Pandit, Dipak Jadhav et al.

Sustainability • 0

<jats:p>Carbon constraints, as well as the growing hazard of greenhouse gas emissions, have accelerated research into all possible renewable energy and fuel sources. Microbial electrolysis cells (MECs), a novel technology able to convert soluble organic matter into energy such as hydrogen gas, represent the most recent breakthrough. While research into energy recovery from wastewater using microbial electrolysis cells is fascinating and a carbon-neutral technology that is still mostly limited to lab-scale applications, much more work on improving the function of microbial electrolysis cells would be required to expand their use in many of these applications. The present limiting issues for effective scaling up of the manufacturing process include the high manufacturing costs of microbial electrolysis cells, their high internal resistance and methanogenesis, and membrane/cathode biofouling. This paper examines the evolution of microbial electrolysis cell technology in terms of hydrogen yield, operational aspects that impact total hydrogen output in optimization studies, and important information on the efficiency of the processes. Moreover, life-cycle assessment of MEC technology in comparison to other technologies has been discussed. According to the results, MEC is at technology readiness level (TRL) 5, which means that it is ready for industrial development, and, according to the techno-economics, it may be commercialized soon due to its carbon-neutral qualities.</jats:p>

Jiaxin Wang, Yanchun Li, Miaomiao Liu et al.

ChemPlusChem • 2020

<jats:title>Abstract</jats:title><jats:p>Microbial electrolysis cells (MECs) is one of the promising biohydrogen production technologies for which low‐cost cathode materials are required and developed to propel the rapid development of MECs. Herein, the preparation of a low‐cost Ce<jats:sub>0.1</jats:sub>−Ni−Y composite is reported by using Y zeolite as carrier loaded with nickel (Ni) and cerium (Ce) as active components and its prominent electrochemical performance. The XPS analysis reveals that strong electronic interaction between Ni and Ce makes a great contribution to the electrochemical performance enhancement. The Ce<jats:sub>0.1</jats:sub>−Ni−Y with a peak current density of 39.8 A⋅m<jats:sup>−2</jats:sup> in LSV, Tafel slope of 40.81 mV⋅dec<jats:sup>−1</jats:sup>, ECSA of 34.3 and hydrogen yield of 0.312±0.013 m<jats:sup>3</jats:sup>⋅m<jats:sup>−3</jats:sup> d<jats:sup>−1</jats:sup> are significantly superior to that of its parent Ni−Y counterpart and rival the performance of commercially Pt/C, which renders it a very promising hydrogen evolution catalyst for MECs.</jats:p>

Ferdy Christian Hartanto, Nadia Nurul Atikah, Mohammad Sahid Indrawan et al.

International Journal of Oil Palm • 0

<jats:p>Palm oil mill effluent contains organic matter and microorganisms that can potentially be reused despite of its impact to the environment. Microbial electrolysis cell is a method that utilizes electrogenic bacteria to produce hydrogen gas. This study aims to explore the potential for utilizing palm oil mill effluent to produce hydrogen gas using microbial electrolysis cells. Experiments were conducted in a specially built MEC reactor with a 3.5 L capacity with 0.5, 1.0, and 1.5 V with carbon fiber cloth as electrodes. A gas analyzer was used to measure hydrogen gas over the course of 24 h at a 2 h interval. Palm oil mill effluent was utilized as a substrate, while distilled water was used as a control. Experiments demonstrate that the amount of hydrogen gas produced increases as the voltage increases, with values of 37 mg m-3 at 0.5 V, 136 mg m-3 at 1.0 V, and 358 mg m-3 at 1.5 V. When comparing the yield of hydrogen gas produced with distilled water substrate at 1.5 V, the yield of palm oil mill effluent substrate is always higher. This could be due to microbial activity increasing the rate of electrolysis of the substrate into hydrogen gas.</jats:p>

Line Schultz Jensen, Christian Kaul, Nilas Brinck Juncker et al.

Energies • 0

<jats:p>The need for renewable and sustainable fuel and energy storage sources is pressing. Biohydrogen has the potential to be a storable energy carrier, a direct fuel and a diverse building block for various downstream products. Utilizing microbial electrolysis cells (MECs) to produce biohydrogen from residue streams, such as the organic fraction of municipal solid waste (OFMSW), agricultural residues and wastewater facilitate utilization and energy recovery from these streams, paving the path for a circular economy. The advantages of using hydrogen include high gravimetric energy density and, given the MEC pathway, the ability to capture heavy metals, ammonia and phosphates from waste streams, thereby allowing for multiple revenue streams emanating from MECs. A review of the MEC technology and its application was carried out to investigate the use of MEC in sustainable biohydrogen production. This review summarizes different MEC designs of varying scales, including anode materials, cathode materials, and configuration possibilities. This review highlights the accomplishments and challenges of small-scale to large-scale MECs. Suggestions for improving the successful upscaling of MECs are listed, thus emphasizing the areas for continued research.</jats:p>

Gunda Mohanakrishna, Ibrahim M. Abu-Reesh, Deepak Pant

Scientific Reports • 0

<jats:title>Abstract</jats:title><jats:p>Petroleum refinery wastewater (PRW) that contains recalcitrant components as the major portion of constituents is difficult to treat by conventional biological processes. Microbial fuel cells (MFCs) which also produce renewable energy were found to be promising for the treatment of PRW. However, due to the high total dissolved solids and low organic matter content, the efficiency of the process is limited. Labaneh whey (LW) wastewater, having higher biodegradability and high organic matter was evaluated as co-substrate along with PRW in standard dual chambered MFC to achieve improved power generation and treatment efficiency. Among several concentrations of LW as co-substrate in the range of 5–30% (v/v) with PRW, 85:15 (PRW:LW) showed to have the highest power generation (power density (PD), 832 mW/m<jats:sup>2</jats:sup>), which is two times higher than the control with PRW as sole substrate (PD, 420 mW/m<jats:sup>2</jats:sup>). On the contrary, a maximum substrate degradation rate of 0.420 kg COD/m<jats:sup>3</jats:sup>-day (ξCOD, 63.10%), was registered with 80:20 feed. Higher LW ratios in PRW lead to the production of VFA which in turn gradually decreased the anolyte pH to below 4.5 (70:30 feed). This resulted in a drop in the performance of MFC with respect to power generation (274 mW/m<jats:sup>2</jats:sup>, 70:30 feed) and substrate degradation (ξCOD, 17.84%).</jats:p>

Cynthia J. Castro, Varun Srinivasan, Joshua Jack et al.

Journal of Water, Sanitation and Hygiene for Development • 2016

<jats:p>Biological electrochemical systems (BESs) have the potential for decentralized treatment in developing countries. A 46 L, two-chamber, hydraulically partitioned microbial fuel cell (MFC) was designed to replicate low-flow scenarios leaving a composting toilet. The co-evolution of electricity and methane in this MFC was evaluated by testing two distinct waste streams: synthetic feces (Case F) and municipal primary effluent (Case W). Oxidation of organic matter was 76 ± 24% during Case F and 67 ± 21% during Case W. Methanogenesis was dominant in the anode, yielding potential power of 3.3 ± 0.64 W/m3 during Case F and 0.40 ± 0.07 W/m3 during Case W. Electrical power production was marginal, Case F = 4.7 ± 0.46 and Case W = 10.6 ± 0.39 μW/m3, although potentially useful in energy-limited areas. Complimentary batch cultivations with anode inocula yielded greater methane production in the presence of graphite. 74 ± 11% more methane was produced with graphite than suspended growth enrichments and 58 ± 10% more than enrichments with non-conductive plastic beads. The co-production of methane and electricity in an MFC may have utility in decentralized treatment. Further work is needed to optimize power from both electricity and methane.</jats:p>

Pranav H. Nakhate, Nandkumar T. Joshi, Kumudini V. Marathe

Reviews in Chemical Engineering • 2017

<jats:title>Abstract</jats:title> <jats:p>Reclamation of wastewater along with minimum energy utilization has been the paramount concern today. Tremendous industrialization and corresponding demographic resulted in elevated water and energy demand; however, scarcity of sufficient water and energy resource triggers rigorous research for sustainable water treatment technology. Recent technologies like activated sludge, filtration, adsorption, coagulation, and oxidation have been considered as promising sustainable technologies, but high cost, low efficiency, and efficacy are the major concerns so far. Wastewater is food for billions of bacteria, where some exceptional bacterial species have the ability to transport electrons that are produced during metabolism to outside the cell membrane. Indeed, wastewater can itself be considered as a prominent candidate to resolve the problem of sustainability. Bioelectrochemical membrane reactor is a promising technology, which is an integration of microbial fuel cell (MFC) to membrane bioreactor (MBR). It promises the benefit of harvesting electricity while biologically treating any type of wastewater to the highest extent while passing wastewater through anaerobic, aerobic, and integrated membrane compartments in successive manner. In this review, we provide critical rethinking to take this idea of integration of MFC-MBR and apply them to produce a fully functional prototype of bioelectrochemical membrane reactor that could be used commercially.</jats:p>

Daniele Molognoni, Stefania Chiarolla, Daniele Cecconet et al.

Water Science and Technology • 2018

<jats:title>Abstract</jats:title> <jats:p>Development of renewable energy sources, efficient industrial processes, energy/chemicals recovery from wastes are research issues that are quite contemporary. Bioelectrochemical processes represent an eco-innovative technology for energy and resources recovery from both domestic and industrial wastewaters. The current study was conducted to: (i) assess bioelectrochemical treatability of industrial (dairy) wastewater by microbial fuel cells (MFCs); (ii) determine the effects of the applied organic loading rate (OLR) on MFC performance; (iii) identify factors responsible for reactor energy recovery losses (i.e. overpotentials). For this purpose, an MFC was built and continuously operated for 72 days, during which the anodic chamber was fed with dairy wastewater and the cathodic chamber with an aerated mineral solution. The study demonstrated that industrial effluents from agrifood facilities can be treated by bioelectrochemical systems (BESs) with &amp;gt;85% (average) organic matter removal, recovering power at an observed maximum density of 27 W m−3. Outcomes were better than in previous (shorter) analogous experiences, and demonstrate that this type of process could be successfully used for dairy wastewater with several advantages.</jats:p>

Sitao Fei, Hao Ren

Micromachines • 0

<jats:p>Nowadays, the development of real-time water quality monitoring sensors is critical. However, traditional water monitoring technologies, such as enzyme-linked immunosorbent assay (ELISA), liquid chromatography, mass spectroscopy, luminescence screening, surface plasma resonance (SPR), and analysis of living bioindicators, are either time consuming or require expensive equipment and special laboratories. Because of the low cost, self-sustainability, direct current output and real-time response, microbial fuel cells (MFCs) have been implemented as biosensors for water toxicity monitoring. In this paper, we report a microscale MFC biosensor to study the dose–response curve of exoelectrogen to toxic compounds in water. The microscale MFC biosensor has an anode chamber volume of 200 μL, which requires less sample consumption for water toxicity monitoring compared with macroscale or mesoscale MFC biosensors. For the first time, the MFC biosensor is exposed to a large formaldehyde concentration range of more than 3 orders of magnitudes, from a low concentration of 1 × 10−6 g/L to a high concentration of 3 × 10−3 g/L in water, while prior studies investigated limited formaldehyde concentration ranges, such as a small concentration range of 1 × 10−4 g/L to 2 × 10−3 g/L or only one high concentration of 0.1 g/L. As a result, for the first time, a sigmoid dose–response relationship of normalized dose–response versus formaldehyde concentration in water is observed, in agreement with traditional toxicology dose–response curve obtained by other measurement techniques. The biosensor has potential applications in determining dose–response curves for toxic compounds and detecting toxic compounds in water.</jats:p>

Cheng Liu, Liang Cheng, Hui Jia

Electroanalysis • 2024

<jats:title>Abstract</jats:title><jats:p>Microbial Fuel Cells (MFCs) represent an innovative approach for transforming biomass energy directly into electricity, which showed great promise in various applications beyond energy generation and wastewater treatment. The use of MFCs as biosensors for in‐situ and online monitoring has garnered increasing interest. These biosensors stand out for their compactness, ease of operation, affordability, and portability. They have proven effectively in the detection of various water quality indicators, including organic matter, nitrogen, heavy metals, pH levels, and dissolved oxygen. This comprehensive review aims to provide a critical analysis of the current research landscape and the latest advancements in MFC technology, with special emphasis on the challenges encountered in its application for wastewater and water quality monitoring. Moreover, strategies for performance improvement, such as the adoption of miniaturized structures, the exploration of innovative materials, and the application of mathematical modelling for analysis, are also discussed. The review also explores potential avenues for future research, especially in the realm of detecting mixed pollutants. Thus, it provides insightful perspectives on the evolving field of biosensor technology based on MFCs.</jats:p>

Ademola Adekunle, Stefano Bambace, Fabrice Tanguay-Rioux et al.

Sensors • 0

<jats:p>A microbial fuel cell (MFC) biosensor with an anode as a sensing element is often unreliable at low or significantly fluctuating organic matter concentrations. To remove this limitation, this work demonstrates capillary action-aided carbon source delivery to an anode-sensing MFC biosensor for use in carbon-depleted environments, e.g., potable water. First, different carbon source delivery configurations using several thread types, silk, nylon, cotton, and polyester, are evaluated. Silk thread was determined to be the most suitable material for passive delivery of a 40 g L−1 acetate solution. This carbon source delivery system was then incorporated into the design of an MFC biosensor for real-time detection of toxicity spikes in tap water, providing an organic matter concentration of 56 ± 15 mg L−1. The biosensor was subsequently able to detect spikes of toxicants such as chlorine, formaldehyde, mercury, and cyanobacterial microcystins. The 16S sequencing results demonstrated the proliferation of Desulfatirhabdium (10.7% of the total population), Pelobacter (10.3%), and Geobacter (10.2%) genera. Overall, this work shows that the proposed approach can be used to achieve real-time toxicant detection by MFC biosensors in carbon-depleted environments.</jats:p>

Trang Nakamoto, Dung Nakamoto, Kozo Taguchi

Biosensors • 0

<jats:p>Wastewater pipelines are present everywhere in urban areas. Wastewater is a preferable fuel for renewable electricity generation from microbial fuel cells. Here, we created an integrated microbial fuel cell pipeline (MFCP) that could be connected to wastewater pipelines and work as an organic content biosensor and energy harvesting device at domestic waste-treatment plants. The MFCP used a pipeline-like terracotta-based membrane, which provided structural support for the MFCP. In addition, the anode and cathode were attached to the inside and outside of the terracotta membrane, respectively. Co−MnO2 was used as a catalyst to improve the performance of the MFCP cathode. The experimental data showed a good linear relationship between wastewater chemical oxygen demand (COD) concentration and the MFCP output voltage in a COD range of 200–1900 mg/L. This result implies the potential of using the MFCP as a sensor to detect the organic content of the wastewater inside the wastewater pipeline. Furthermore, the MFCP can be used as a long-lasting sustainable energy harvester with a maximum power density of 400 mW/m2 harvested from 1900 mg/L COD wastewater at 25 °C.</jats:p>

Baoguo Wu, Hui Yu, Chong Lin et al.

ChemElectroChem • 2015

<jats:title>Abstract</jats:title><jats:p>The maximum current density (<jats:italic>j</jats:italic><jats:sub>max</jats:sub>) is of importance to the modeling of current produced in a bioelectrochemical system (BES). This study explores an alternative to biomass and biofilm thickness, the accumulated charge density (<jats:italic>τ</jats:italic>) of electroactive bacteria on the bioanode, to estimate the <jats:italic>j</jats:italic><jats:sub>max</jats:sub> value. The <jats:italic>τ</jats:italic> values of five carbon‐based bioanodes are chronoamperometrically determined in a substrate‐depleted solution. The graphite felt bioanode acclimated for 1, 2, 4, and 6 batches exhibits <jats:italic>τ</jats:italic> values of 6.14, 11.80, 22.23, and 30.24 C m<jats:sup>−2</jats:sup>, respectively, and <jats:italic>j</jats:italic><jats:sub>max</jats:sub> values of 5.31, 6.69, 14.01, and 19.62 A m<jats:sup>−2</jats:sup>, respectively. A linear correlation between <jats:italic>τ</jats:italic> and <jats:italic>j</jats:italic><jats:sub>max</jats:sub> is achieved and can be expressed as <jats:italic>j</jats:italic><jats:sub>max</jats:sub>=0.64<jats:italic>τ</jats:italic>. The <jats:italic>τ</jats:italic> and <jats:italic>j</jats:italic><jats:sub>max</jats:sub> values of four other carbon‐based bioanodes also follow a linear relationship, with coefficients of approximately 0.64. These results imply that <jats:italic>τ</jats:italic> is a key parameter for estimating <jats:italic>j</jats:italic><jats:sub>max</jats:sub> in the BES without the need to determine biomass and biofilm thickness.</jats:p>

Alana Danielle Dunne, Madalyn D. Puckett, Nicole Elizabeth Yuede et al.

ECS Meeting Abstracts • 2019

<jats:p> Microbial fuel cells (MFCs) have gained attention as a renewable energy option due to the utilization of microbes as catalysts for the oxidation of natural substrates. In order to increase the practical application of MFC technology, the overall system must enhance power output and lower operational costs. More specifically, the bacteria must dock on the electrode surface to allow for efficient electron transfer mechanisms. In efforts to increase productive bacteria-surface interactions, this work focuses on the synthesis of a conductive, cellulose-based nanocomposite for use as anodic electrodes. The nanocomposite material was non-covalently modified through the incorporation of sugar-functionalized TiO<jats:sub>2</jats:sub> nanoparticles. The relationship between conductivity and biocompatibility was explored in order to optimize the interactions between the synthesized electrodes and <jats:italic>Escherichia coli</jats:italic> (<jats:italic>E. Coli</jats:italic>). Power production using the composite electrodes was correlated to biofilm formation and cell proliferation via atomic force microscopy (AFM) and live/dead stain, respectively. The composite electrode materials have shown increased electrical response over traditional carbon cloth when used as anodes under dye-mediated conditions. Additionally, the sugar-functionalized composites showed increased bacterial adsorption and enhanced cell viability indicating more intimate contact between the microbes and the electrode surface. Initial results also suggest photochemical activity using sugar, polyaniline modified TiO<jats:sub>2</jats:sub> nanoparticles embedded within the cellulose matrix resulting in responsive fuel cell behavior. Future work aims to incorporate supramolecular structures, such as β-cyclodextrin, to constrain dye absorption to the material surface and potentially increase the electrical response and longevity of the fuel cell system. </jats:p>

Hengliang Zhang, Fei Xing, Liang Duan et al.

Bioresource Technology • 2025

Yating Guo, Guozhen Wang, Hao Zhang et al.

Biotechnology for Biofuels • 2020

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>Extracellular electron transfer (EET) is essential in improving the power generation performance of electrochemically active bacteria (EAB) in microbial fuel cells (MFCs). Currently, the EET mechanisms of dissimilatory metal-reducing (DMR) model bacteria <jats:italic>Shewanella oneidensis</jats:italic> and <jats:italic>Geobacter sulfurreducens</jats:italic> have been thoroughly studied. <jats:italic>Klebsiella</jats:italic> has also been proved to be an EAB capable of EET, but the EET mechanism has not been perfected. This study investigated the effects of biofilm transfer and electron mediators transfer on <jats:italic>Klebsiella quasipneumoniae</jats:italic> sp. 203 electricity generation performance in MFCs.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>Herein, we covered the anode of MFC with a layer of microfiltration membrane to block the effect of the biofilm mechanism, and then explore the EET of the electron mediator mechanism of <jats:italic>K. quasipneumoniae</jats:italic> sp. 203 and electricity generation performance. In the absence of short-range electron transfer, we found that <jats:italic>K. quasipneumoniae</jats:italic> sp. 203 can still produce a certain power generation performance, and coated-MFC reached 40.26 mW/m<jats:sup>2</jats:sup> at a current density of 770.9 mA/m<jats:sup>2,</jats:sup> whereas the uncoated-MFC reached 90.69 mW/m<jats:sup>2</jats:sup> at a current density of 1224.49 mA/m<jats:sup>2</jats:sup>. The difference in the electricity generation performance between coated-MFC and uncoated-MFC was probably due to the microfiltration membrane covered in anode, which inhibited the growth of EAB on the anode. Therefore, we speculated that <jats:italic>K. quasipneumoniae</jats:italic> sp. 203 can also perform EET through the biofilm mechanism. The protein content, the integrity of biofilm and the biofilm activity all proved that the difference in the electricity generation performance between coated-MFC and uncoated-MFC was due to the extremely little biomass of the anode biofilm. To further verify the effect of electron mediators on electricity generation performance of MFCs, 10 µM 2,6-DTBBQ, 2,6-DTBHQ and DHNA were added to coated-MFC and uncoated-MFC. Combining the time–voltage curve and CV curve, we found that 2,6-DTBBQ and 2,6-DTBHQ had high electrocatalytic activity toward the redox reaction of <jats:italic>K. quasipneumoniae</jats:italic> sp. 203-inoculated MFCs. It was also speculated that <jats:italic>K. quasipneumoniae</jats:italic> sp. 203 produced 2,6-DTBHQ and 2,6-DTBBQ.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>To the best of our knowledge, the three modes of EET did not exist separately. <jats:italic>K. quasipneumoniae</jats:italic> sp.203 will adopt the corresponding electron transfer mode or multiple ways to realize EET according to the living environment to improve electricity generation performance.</jats:p> </jats:sec>