Discover insights from thousands of peer-reviewed papers on microbial electrochemical systems
Thanh-Hai Le, Yukyung Kim, Hyeonseok Yoon
Polymers · 2017
Conducting polymers (CPs) have received much attention in both fundamental and practical studies because they have electrical and electrochemical properties similar to those of both traditional semiconductors and metals. CPs possess excellent characteristics such as mild synthesis and processing conditions, chemical and structural diversity, tunable conductivity, and structural flexibility. Advances in nanotechnology have allowed the fabrication of versatile CP nanomaterials with improved performance for various applications including electronics, optoelectronics, sensors, and energy devices. The aim of this review is to explore the conductivity mechanisms and electrical and electrochemical properties of CPs and to discuss the factors that significantly affect these properties. The size and morphology of the materials are also discussed as key parameters that affect their major properties. Finally, the latest trends in research on electrochemical capacitors and sensors are introduced through an in-depth discussion of the most remarkable studies reported since 2003.
M. P. Browne, Edurne Redondo, M. Pumera
Chemical Reviews · 2020
Additive manufacturing (also known as three-dimensional (3D) printing) is being extensively utilized in many areas of electrochemistry to produce electrodes and devices, as this technique allows for fast prototyping and is relatively low cost. Furthermore, there is a variety of 3D-printing technologies available, which include fused deposition modeling (FDM), inkjet printing, select laser melting (SLM), and stereolithography (SLA), making additive manufacturing a highly desirable technique for electrochemical purposes. In particular, over the last number of years, a significant amount of research into using 3D printing to create electrodes/devices for electrochemical energy conversion and storage has emerged. Strides have been made in this area; however, there are still a number of challenges and drawbacks that need to be overcome in order to 3D print active and stable electrodes/devices for electrochemical energy conversion and storage to rival that of the state-of-the-art. In this Review, we will give an overview of the reasoning behind using 3D printing for these electrochemical applications. We will then discuss how the electrochemical performance of the electrodes/devices are affected by the various 3D-printing technologies and by manipulating the 3D-printed electrodes by post modification techniques. Finally, we will give our insights into the future perspectives of this exciting field based on our discussion through this Review.
M. Gaberšček
Nature Communications · 2021
Lithium-based batteries are a class of electrochemical energy storage devices where the potentiality of electrochemical impedance spectroscopy (EIS) for understanding the battery charge storage mechanisms is still to be fully exploited. Generally considered as an ancillary technique, the application of EIS should be promoted focusing on improved experimental design of experiments and advanced data analysis using physics-based models. Electrochemical impedance spectroscopy is a key technique for understanding Li-based battery processes. Here, the authors discuss the current state of the art, advantages and challenges of this technique, also giving an outlook for future developments.
Yuanyuan Jiang, Pengjuan Ni, Chuanxia Chen et al.
Advanced Energy Materials · 2018
Direct electrochemical production of hydrogen peroxide (H2O2) through two‐electron oxygen electrochemistry, for example, the oxygen reduction in fuel cells or water oxidation in water electrolyzers, could provide an attractive alternative to locally produce this chemical on demand. The efficiency of these processes depends greatly on the availability of cost‐effective catalysts with high selectivity, activity, and stability. In recent years, various novel nanostructured materials have been reported to selectively produce H2O2. Through combined experimental and theoretical approaches, underlying mechanisms in the electrochemical synthesis of H2O2 via oxygen electrochemistry have been unveiled. Considering the remarkable progress in this area, the authors summarize recent developments regarding the direct production of H2O2 through two‐electron electrochemical oxygen reactions. The fundamental aspects of electrochemical oxygen reactions are first introduced. Various types of catalysts that can effectively produce H2O2 via two‐electron oxygen electrochemistry are then presented. In parallel, the unique structure‐, component‐, and composition‐dependent electrochemical performance together with the underlying catalytic mechanisms are discussed. Finally, a brief conclusion about the recent progress achieved in electrochemical generation of H2O2 and an outlook on future research challenges are given.
Tammo K. Schwietert, V. Arszelewska, Chao Wang et al.
Nature Materials · 2019
All-solid-state Li-ion batteries promise safer electrochemical energy storage with larger volumetric and gravimetric energy densities. A major concern is the limited electrochemical stability of solid electrolytes and related detrimental electrochemical reactions, especially because of our restricted understanding. Here we demonstrate for the argyrodite-, garnet- and NASICON-type solid electrolytes that the favourable decomposition pathway is indirect rather than direct, via (de)lithiated states of the solid electrolyte, into the thermodynamically stable decomposition products. The consequence is that the electrochemical stability window of the solid electrolyte is notably larger than predicted for direct decomposition, rationalizing the observed stability window. The observed argyrodite metastable (de)lithiated solid electrolyte phases contribute to the (ir)reversible cycling capacity of all-solid-state batteries, in addition to the contribution of the decomposition products, comprehensively explaining solid electrolyte redox activity. The fundamental nature of the proposed mechanism suggests this is a key aspect for solid electrolytes in general, guiding interface and material design for all-solid-state batteries. Although all-solid-state Li-ion batteries exhibit enhanced energy densities, electrochemical stability of solid electrolytes remains a challenge. A mechanism explaining the relationship between redox activity and electrochemical stability for typical solid electrolytes is now proposed.
Ruud Kortlever, Jing Shen, K. Schouten et al.
The Journal of Physical Chemistry Letters · 2015
The electrochemical reduction of CO2 has gained significant interest recently as it has the potential to trigger a sustainable solar-fuel-based economy. In this Perspective, we highlight several heterogeneous and molecular electrocatalysts for the reduction of CO2 and discuss the reaction pathways through which they form various products. Among those, copper is a unique catalyst as it yields hydrocarbon products, mostly methane, ethylene, and ethanol, with acceptable efficiencies. As a result, substantial effort has been invested to determine the special catalytic properties of copper and to elucidate the mechanism through which hydrocarbons are formed. These mechanistic insights, together with mechanistic insights of CO2 reduction on other metals and molecular complexes, can provide crucial guidelines for the design of future catalyst materials able to efficiently and selectively reduce CO2 to useful products.
Zhigang Geng, Yan Liu, Xiangdong Kong et al.
Advanced Materials · 2018
The electrochemical reduction of N2 into NH3 production under ambient conditions represents an attractive prospect for the fixation of N2. However, this process suffers from low yield rate of NH3 over reported electrocatalysts. In this work, a record‐high activity for N2 electrochemical reduction over Ru single atoms distributed on nitrogen‐doped carbon (Ru SAs/N‐C) is reported. At −0.2 V versus reversible hydrogen electrode, Ru SAs/N‐C achieves a Faradaic efficiency of 29.6% for NH3 production with partial current density of −0.13 mA cm−2. Notably, the yield rate of Ru SAs/N‐C reaches 120.9 μgNH3 mgcat.−1 h−1 , which is one order of magnitude higher than the highest value ever reported. This work not only develops a superior electrocatalyst for NH3 production, but also provides a guideline for the rational design of highly active and robust single‐atom catalysts.
Dongbin Xiong, Xifei Li, Z. Bai et al.
Small · 2018
Ti3 C2 Tx , a typical representative among the emerging family of 2D layered transition metal carbides and/or nitrides referred to as MXenes, has exhibited multiple advantages including metallic conductivity, a plastic layer structure, small band gaps, and the hydrophilic nature of its functionalized surface. As a result, this 2D material is intensively investigated for application in the energy storage field. The composition, morphology and texture, surface chemistry, and structural configuration of Ti3 C2 Tx directly influence its electrochemical performance, e.g., the use of a well-designed 2D Ti3 C2 Tx as a rechargeable battery anode has significantly enhanced battery performance by providing more chemically active interfaces, shortened ion-diffusion lengths, and improved in-plane carrier/charge-transport kinetics. Some recent progresses of Ti3 C2 Tx MXene are achieved in energy storage. This Review summarizes recent advances in the synthesis and electrochemical energy storage applications of Ti3 C2 Tx MXene including supercapacitors, lithium-ion batteries, sodium-ion batteries, and lithium-sulfur batteries. The current opportunities and future challenges of Ti3 C2 Tx MXene are addressed for energy-storage devices. This Review seeks to provide a rational and in-depth understanding of the relation between the electrochemical performance and the nanostructural/chemical composition of Ti3 C2 Tx , which will promote the further development of 2D MXenes in energy-storage applications.
Yong Yuan, A. Lei
Accounts of Chemical Research · 2019
Oxidative cross-coupling has proved to be one of the most straightforward strategies for forming carbon-carbon and carbon-heteroatom bonds from easily available precursors. Over the past two decades, tremendous efforts have been devoted in this field and significant advances have been achieved. However, in order to remove the surplus electrons from substrates for chemical bonds formation, stoichiometric oxidants are usually needed. Along with the development of modern sustainable chemistry, considerable efforts have been devoted to perform the oxidative cross-coupling reactions under external-oxidant-free conditions. Electrochemical synthesis is a powerful and environmentally benign approach, which can not only achieve the oxidative cross-couplings under external-oxidant-free conditions, but also release valuable hydrogen gas during the chemical bond formation. Recently, the electrochemical oxidative cross-coupling with hydrogen evolution reactions has been significantly explored. This Account presents our recent efforts toward the development of electrochemical oxidative cross-coupling with hydrogen evolution reactions. (1) We explored the oxidative cross-coupling of thiols/thiophenols with arenes, heteroarenes, and alkenes for C-S bond formation. (2) Using the strategy of electrochemical oxidative C-H/N-H cross-coupling with hydrogen evolution, we successfully realized the C-H amination of phenols, anilines, imidazopyridines, and even ethers. (3) Employing halide salts as the green halogenating reagents, we developed a clean C-H halogenation protocol under electrochemical oxidation conditions. To address the limitation that this reaction had to carry out in aqueous solvent, we also developed an alternative method that uses CBr4, CHBr3, CH2Br2, CCl3Br, and CCl4 as halogenating reagents and the mixture of acetonitrile and methanol as cosolvent. (4) We also developed an approach for constructing C-O bonds in a well-developed electrochemical oxidative cross-coupling with hydrogen evolution manner. (5) Under mild external-oxidant-free electrochemical conditions, we realized the C(sp2)-H and C(sp3)-H phosphonylation with modest to high yields. (6) We successfully achieved the S-H/S-H cross-coupling with hydrogen evolution under electrochemical oxidation conditions. By anodic oxidation instead of chemical oxidants, the overoxidation of thiols and thiophenols was well avoided. (7) The methods for constructing structurally diverse heterocyclic compounds were also developed via the electrochemical oxidative annulations. (8) We have also applied the electrochemical oxidative cross-coupling with hydrogen evolution strategy to the alkenes difunctionalization for constructing multiple bonds in one step, such as C-S/C-O bonds, C-S/C-N bonds, C-Se/C-O bonds, and C-Se/C-N bonds. We hope our studies will stimulate the research interest of chemists and pave the way for the discovery of more electrochemical oxidative cross-coupling with hydrogen evolution reactions.
Na Han, P. Ding, Le He et al.
Advanced Energy Materials · 2019
Selective CO2 reduction to formic acid or formate is the most technologically and economically viable approach to realize electrochemical CO2 valorization. Main group metal–based (Sn, Bi, In, Pb, and Sb) nanostructured materials hold great promise, but are still confronted with several challenges. Here, the current status, challenges, and future opportunities of main group metal–based nanostructured materials for electrochemical CO2 reduction to formate are reviewed. Firstly, the fundamentals of electrochemical CO2 reduction are presented, including the technoeconomic viability of different products, possible reaction pathways, standard experimental procedure, and performance figures of merit. This is then followed by detailed discussions about different types of main group metal–based electrocatalyst materials, with an emphasis on underlying material design principles for promoting the reaction activity, selectivity, and stability. Subsequently, recent efforts on flow cells and membrane electrode assembly cells are reviewed so as to promote the current density as well as mechanistic studies using in situ characterization techniques. To conclude a short perspective is offered about the future opportunities and directions of this exciting field.
Joseph Wang
Chemical Reviews · 2008
First-generation glucose biosensors relied on the use of the natural oxygen cosubstrate and the production and detection of hydrogen peroxide and were much simpler, especially when miniaturized sensors are concerned. More sophisticated bioelectronic systems for enhancing the electrical response, based on patterned monolayer or multilayer assemblies and organized enzyme networks on solid electrodes, have been developed for contacting GOx with the electrode support. Electrochemical biosensors are well suited for satisfying the needs of personal (home) glucose testing, and the majority of personal blood glucose meters are based on disposable (screen-printed) enzyme electrode test strips, which are mass produced by the thick film (screen-printing) microfabrication technology. In the counter and an additional “baseline” working electrode, various membranes (mesh) are incorporated into the test strips along with surfactants, to provide a uniform sample coverage. Such devices offer considerable promise for obtaining the desired clinical information in a simpler, user-friendly, faster, and cheaper manner compared to traditional assays. Continuous ex-vivo monitoring of blood glucose was proposed in 1974 and the majority of glucose sensors used for in-vivo applications are based on the GOx-catalyzed oxidation of glucose by oxygen. The major factors that play a role in the development of clinically accurate in-vivo glucose sensors include issues related to biocompatibility, miniaturization, long-term stability of the enzyme and transducer, oxygen deficit, short stabilization times, in-vivo calibration, baseline drift, safety, and convenience.
Yao Zheng, Anthony Vasileff, Xianlong Zhou et al.
Journal of the American Chemical Society · 2019
Electrochemical reduction of CO2 to high-energy-density oxygenates and hydrocarbons beyond CO is important for long-term and large-scale renewable energy storage. However, the key step of the C-C bond formation needed for the generation of C2 products induces an additional barrier on the reaction. This inevitably creates larger overpotentials and greater variety of products as compared to the conversion of CO2 to C1 products. Therefore, an in-depth understanding of the catalytic mechanism is required for advancing the design of efficient electrocatalysts to control the reaction pathway to the desired products. Herein, we present a critical appraisal of reduction of CO2 to C2 products focusing on the connection between the fundamentals of reaction and efficient electrocatalysts. An in-depth discussion of the mechanistic aspects of various C2 reaction pathways on copper-based catalysts is presented together with consideration of practical factors under electrocatalytic operating conditions. By providing some typical examples illustrating the benefit of merging theoretical calculations, surface characterization, and electrochemical measurements, we try to address the key issues of the ongoing debate toward better understanding electrochemical reduction of CO2 at the atomic level and envisioning the roadmap for C2 products generation.
Shuo Wang, Q. Bai, Adelaide M. Nolan et al.
Angewandte Chemie International Edition · 2019
Enabling all-solid-state Li-ion batteries requires solid electrolytes with high Li ionic conductivity and good electrochemical stability. Following recent experimental reports of Li3 YCl6 and Li3 YBr6 as promising new solid electrolytes, we used first principles computation to investigate the Li-ion diffusion, electrochemical stability, and interface stability of chloride and bromide materials and elucidated the origin of their high ionic conductivities and good electrochemical stabilities. Chloride and bromide chemistries intrinsically exhibit low migration energy barriers, wide electrochemical windows, and are not constrained to previous design principles for sulfide and oxide Li-ion conductors, allowing for much greater freedom in structure, chemistry, composition, and Li sublattice for developing fast Li-ion conductors. Our study highlights chloride and bromide chemistries as a promising new research direction for solid electrolytes with high ionic conductivity and good stability.
Yuyan Shao, Jun Wang, Hong Wu et al.
Electroanalysis · 2010
Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). This article selectively reviews recent advances in graphene-based electrochemical sensors and biosensors. In particular, graphene for direct electrochemistry of enzyme, its electrocatalytic activity toward small biomolecules (hydrogen peroxide, NADH, dopamine, etc.), and graphenebased enzyme biosensors have been summarized in more detail; Graphene-based DNA sensing and environmental analysis have been discussed. Future perspectives in this rapidly developing field are also discussed.
Laiquan Li, Cheng Tang, Yao Zheng et al.
Advanced Energy Materials · 2020
The electrochemical reduction of O2 via a two‐electron reaction pathway to H2O2 provides a possibility for replacing the current anthraquinone process, enabling sustainable and decentralized H2O2 production. Here, a nitrogen‐rich few‐layered graphene (N‐FLG) with a tunable nitrogen configuration is developed for electrochemical H2O2 generation. A positive correlation between the content of pyrrolic‐N and the H2O2 selectivity is experimentally observed. The critical role of pyrrolic‐N is elucidated by the variable intermediate adsorption profiles as well as the dependent negative shifts of the pyrrolic‐N peak on X‐ray adsorption near edge structure spectra. By virtue of the optimized N doping configuration and the unique porous structure, the as‐fabricated N‐FLG electrocatalyst exhibits high selectivity toward electrochemical H2O2 synthesis as well as superior long‐term stability. To achieve high‐value products on both the anode and cathode with optimized energy efficiency, a practical device coupling electrochemical H2O2 generation and furfural oxidation is assembled, simultaneously enabling a high yield rate of H2O2 at the cathode (9.66 mol h−1 gcat−1) and 2‐furoic acid at the anode (2.076 mol m−2 h−1) under a small cell voltage of 1.8 V.
Guoqiang Zhao, Kun Rui, S. Dou et al.
Advanced Functional Materials · 2018
Developing sustainable and renewable energy sources along with efficient energy storage and conversion technologies is vital to address environmental and energy challenges. Electrochemical water splitting coupling with grid‐scale renewable energy harvesting technologies is becoming one of the most promising approaches. Besides, hydrogen with the highest mass‐energy density of any fuel is regarded as the ultimate clean energy carrier. The realization of practical water splitting depends heavily on the development of low‐cost, highly active, and durable catalysts for hydrogen evolution reactions (HERs) and oxygen evolution reactions (OERs). Recently, heterostructured catalysts, which are generally composed of electrochemical active materials and various functional additives, have demonstrated extraordinary electrocatalytic performance toward HER and OER, and particularly a number of precious‐metal‐free heterostructures delivered comparable activity with precious‐metal‐based catalysts. Herein, an overview is presented of recent research progress on heterostructured HER catalysts. It starts with summarizing the fundamentals of HER and approaches for evaluating HER activity. Then, the design and synthesis of heterostructures, electrochemical performance, and the related mechanisms for performance enhancement are discussed. Finally, the future opportunities and challenges are highlighted for the development of heterostructured HER catalysts from the points of view of both fundamental understandings and practical applications.
Abhishek Sarkar, Qingsong Wang, Alexander Schiele et al.
Advanced Materials · 2019
High‐entropy materials, especially high‐entropy alloys and oxides, have gained significant interest over the years due to their unique structural characteristics and correlated possibilities for tailoring of functional properties. The developments in the area of high‐entropy oxides are highlighted here, with emphasis placed on their fundamental understanding, including entropy‐dominated phase‐stabilization effects and prospective applications, e.g., in the field of electrochemical energy storage. Critical comments on the different classes of high‐entropy oxides are made and the underlying principles for the observed properties are summarized. The diversity of materials design, provided by the entropy‐mediated phase‐stabilization concept, allows engineering of new oxide candidates for practical applications, warranting further studies in this emerging field of materials science.
Shaohua Chen, L. Qiu, Hui‐Ming Cheng
Chemical Reviews · 2020
Advanced electrochemical energy storage devices (EESDs) that can store electrical energy efficiently while being miniature/flexible/wearable/load-bearing are much needed for various applications ranging from flexible/wearable/portable electronics to lightweight electric vehicles/aerospace equipment. Carbon-based fibers hold great promise in the development of these advanced EESDs (e.g., supercapacitors and batteries) due to their being lightweight, high electrical conductivity, excellent mechanical strength, flexibility, and tunable electrochemical performance. This review summarizes the fabrication techniques of carbon-based fibers, especially carbon nanofibers, carbon-nanotube-based fibers, and graphene-based fibers, and various strategies for improving their mechanical, electrical, and electrochemical performance. The design, assembly, and potential applications of advanced EESDs from these carbon-based fibers are highlighted. Finally, the challenges and future opportunities of carbon-based fibers for advanced EESDs are discussed.
Lei Fan, Chuan Xia, Peng Zhu et al.
Nature Communications · 2020
Electrochemical CO2 reduction reaction (CO2RR) to liquid fuels is currently challenged by low product concentrations, as well as their mixture with traditional liquid electrolytes, such as KHCO3 solution. Here we report an all-solid-state electrochemical CO2RR system for continuous generation of high-purity and high-concentration formic acid vapors and solutions. The cathode and anode were separated by a porous solid electrolyte (PSE) layer, where electrochemically generated formate and proton were recombined to form molecular formic acid. The generated formic acid can be efficiently removed in the form of vapors via inert gas stream flowing through the PSE layer. Coupling with a high activity (formate partial current densities ~450 mA cm−2), selectivity (maximal Faradaic efficiency ~97%), and stability (100 hours) grain boundary-enriched bismuth catalyst, we demonstrated ultra-high concentrations of pure formic acid solutions (up to nearly 100 wt.%) condensed from generated vapors via flexible tuning of the carrier gas stream. Electrochemical CO2 reduction to liquid fuels is limited by low product concentrations and formation of mixtures with traditional liquid electrolytes. Here the authors report an all-solid-state system for a continuous generation of high-purity and high-concentration formic acid vapors and solutions.
Hao Wang, Jianmin Li, Ke Li et al.
Chemical Society Reviews · 2020
Transition metal nitrides (TMNs), by virtue of their unique electronic structure, high electrical conductivity, superior chemical stability, and excellent mechanical robustness, have triggered tremendous research interest over the past decade, and showed great potential for electrochemical energy conversion and storage. However, bulk TMNs usually suffer from limited numbers of active sites and sluggish ionic kinetics, and eventually ordinary electrochemical performance. Designing nanostructured TMNs with tailored morphology and good dispersity has proved an effective strategy to address these issues, which provides a larger specific surface area, more abundant active sites, and shorter ion and mass transport distances over the bulk counterparts. Herein, the most up-to-date progress on TMN-based nanomaterials is comprehensively reviewed, focusing on geometric-structure design, electronic-structure engineering, and applications in electrochemical energy conversion and storage, including electrocatalysis, supercapacitors, and rechargeable batteries. Finally, we outline the future challenges of TMN-based nanomaterials and their possible research directions beyond electrochemical energy applications.
Lei Fan, Chuan Xia, Fangqi Yang et al.
Science Advances · 2020
Recent progress about electrochemical CO2 reduction toward C2+ products is reviewed. In light of environmental concerns and energy transition, electrochemical CO2 reduction (ECR) to value-added multicarbon (C2+) fuels and chemicals, using renewable electricity, presents an elegant long-term solution to close the carbon cycle with added economic benefits as well. However, electrocatalytic C─C coupling in aqueous electrolytes is still an open challenge due to low selectivity, activity, and stability. Design of catalysts and reactors holds the key to addressing those challenges. We summarize recent progress in how to achieve efficient C─C coupling via ECR, with emphasis on strategies in electrocatalysts and electrocatalytic electrode/reactor design, and their corresponding mechanisms. In addition, current bottlenecks and future opportunities for C2+ product generation is discussed. We aim to provide a detailed review of the state-of-the-art C─C coupling strategies to the community for further development and inspiration in both fundamental understanding and technological applications.
Il-Hoon Cho, Dong Hyung Kim, Sangsoo Park
Biomaterials Research · 2020
Background The electrochemical biosensor is one of the typical sensing devices based on transducing the biochemical events to electrical signals. In this type of sensor, an electrode is a key component that is employed as a solid support for immobilization of biomolecules and electron movement. Thanks to numerous nanomaterials that possess the large surface area, synergic effects are enabled by improving loading capacity and the mass transport of reactants for achieving high performance in terms of analytical sensitivity. Main body We categorized the current electrochemical biosensors into two groups, carbon-based (carbon nanotubes and graphene) and non-carbon-based nanomaterials (metallic and silica nanoparticles, nanowire, and indium tin oxide, organic materials). The carbon allotropes can be employed as an electrode and supporting scaffolds due to their large active surface area as well as an effective electron transfer rate. We also discussed the non-carbon nanomaterials that are used as alternative supporting components of the electrode for improving the electrochemical properties of biosensors. Conclusion Although several functional nanomaterials have provided the innovative solid substrate for high performances, developing on-site version of biosensor that meets enough sensitivity along with high reproducibility still remains a challenge. In particular, the matrix interference from real samples which seriously affects the biomolecular interaction still remains the most critical issues that need to be solved for practical aspect in the electrochemical biosensor.
C. Brett
Molecules · 2022
Electrochemical impedance spectroscopy is finding increasing use in electrochemical sensors and biosensors, both in their characterisation, including during successive phases of sensor construction, and in application as a quantitative determination technique. Much of the published work continues to make little use of all the information that can be furnished by full physical modelling and analysis of the impedance spectra, and thus does not throw more than a superficial light on the processes occurring. Analysis is often restricted to estimating values of charge transfer resistances without interpretation and ignoring other electrical equivalent circuit components. In this article, the important basics of electrochemical impedance for electrochemical sensors and biosensors are presented, focussing on the necessary electrical circuit elements. This is followed by examples of its use in characterisation and in electroanalytical applications, at the same time demonstrating how fuller use can be made of the information obtained from complete modelling and analysis of the data in the spectra, the values of the circuit components and their physical meaning. The future outlook for electrochemical impedance in the sensing field is discussed.
Youbing Li, Huixia Shao, Zifeng Lin et al.
Nature Materials · 2019
Two-dimensional carbides and nitrides of transition metals, known as MXenes, are a fast-growing family of materials that have attracted attention as energy storage materials. MXenes are mainly prepared from Al-containing MAX phases (where A = Al) by Al dissolution in F-containing solution; most other MAX phases have not been explored. Here a redox-controlled A-site etching of MAX phases in Lewis acidic melts is proposed and validated by the synthesis of various MXenes from unconventional MAX-phase precursors with A elements Si, Zn and Ga. A negative electrode of Ti 3 C 2 MXene material obtained through this molten salt synthesis method delivers a Li + storage capacity of up to 738 C g −1 (205 mAh g −1 ) with high charge–discharge rate and a pseudocapacitive-like electrochemical signature in 1 M LiPF 6 carbonate-based electrolyte. MXenes prepared via this molten salt synthesis route may prove suitable for use as high-rate negative-electrode materials for electrochemical energy storage applications. Two-dimensional transition metal carbides and nitrides, known as MXenes, are currently considered as energy storage materials. A generic Lewis acidic etching route for preparing high-rate negative-electrode MXenes with enhanced electrochemical performance in non-aqueous electrolyte is now proposed.
Tyler S. Mathis, Narendra Kurra, Xuehang Wang et al.
Advanced Energy Materials · 2019
Due to the tremendous importance of electrochemical energy storage, numerous new materials and electrode architectures for batteries and supercapacitors have emerged in recent years. Correctly characterizing these systems requires considerable time, effort, and experience to ensure proper metrics are reported. Many new nanomaterials show electrochemical behavior somewhere in between conventional double‐layer capacitor and battery electrode materials, making their characterization a non‐straightforward task. It is understandable that some researchers may be misinformed about how to rigorously characterize their materials and devices, which can result in inflation of their reported data. This is not uncommon considering the current state of the field nearly requires record breaking performance for publication in high‐impact journals. Incorrect characterization and data reporting misleads both the materials and device development communities, and it is the shared responsibility of the community to follow rigorous reporting methodologies to ensure published results are reliable to ensure constructive progress. This tutorial aims to clarify the main causes of inaccurate data reporting and to give examples of how researchers should proceed. The best practices for measuring and reporting metrics such as capacitance, capacity, coulombic and energy efficiencies, electrochemical impedance, and the energy and power densities of capacitive and pseudocapacitive materials are discussed.
Jiahui Wu, Qiaoting Yang, Qian Li et al.
Analytical Chemistry · 2021
Traditional peroxidase-like nanozyme-based sensors suffer from self-decomposition and high toxicity of H2O2, as well as the interference of color from nanozymes themselves and testing samples. In this work, we adopt nanozymes (two-dimension (2D) MnO2 sheets, manganese dioxide nanosheets (MnNS)) with oxidase-like and peroxidase-like properties as advanced catalysts to develop a novel homogeneous electrochemical sensor for organophosphate pesticides (OPs) using dissolved O2 as a coreactant without the interference of H2O2 and color. Owing to the large surface area and unique catalytic activity of MnNS, a large amount of tetramethylbenzidine (TMB) is catalyzed oxidation, leading to a significantly declined differential pulse voltammetry (DPV) current. Obviously, MnNS display an excellent response to thiocholine, deriving from the catalyzing hydrolysis of acetylthiocholine (ATCh) by acetylcholinesterase (AChE), which switches a homogeneous electrochemical OP detection process based on the depressing AChE activity with a limit of detection (LOD) of 0.025 ng mL-1. The as-proposed strategy on using nanozymes with oxidase-like and peroxidase-like properties to develop a homogeneous electrochemical sensor will provide a new pathway for improving the performance of nanozyme-based sensors, and the established MnNS-based homogeneous electrochemical sensor will find more applications for OP residue determination in food samples.
Woosung Choi, Heon-Cheol Shin, Ji Man Kim et al.
Journal of Electrochemical Science and Technology · 2020
As research on secondary batteries becomes important, interest in analytical methods to examine the condition of secondary batteries is also increasing. Among these methods, the electrochemical impedance spectroscopy (EIS) method is one of the most attractive diagnostic techniques due to its convenience, quickness, accuracy, and low cost. However, since the obtained spectra are complicated signals representing several impedance elements, it is necessary to understand the whole electrochemical environment for a meaningful analysis. Based on the understanding of the whole system, the circuit elements constituting the cell can be obtained through construction of a physically sound circuit model. Therefore, this mini-review will explain how to construct a physically sound circuit model according to the characteristics of the battery cell system and then introduce the relationship between the obtained resistances of the bulk (Rb), charge transfer reaction (Rct), interface layer (RSEI), diffusion process (W) and battery characteristics, such as the state of charge (SOC), temperature, and state of health (SOH).
Xiaojia Zhao, Pradip Pachfule, Arne Thomas
Chemical Society Reviews · 2021
Covalent organic frameworks are a class of extended crystalline organic materials that possess unique architectures with high surface areas and tuneable pore sizes. Since the first discovery of the topological frameworks in 2005, COFs have been applied as promising materials in diverse areas such as separation and purification, sensing or catalysis. Considering the need for renewable and clean energy production, many research efforts have recently focused on the application of porous materials for electrochemical energy storage and conversion. In this respect, considerable efforts have been devoted to the design and synthesis of COF-based materials for electrochemical applications, including electrodes and membranes for fuel cells, supercapacitors and batteries. This review article highlights the design principles and strategies for the synthesis of COFs with a special focus on their potential for electrochemical applications. Recently suggested hybrid COF materials or COFs with hierarchical porosity will be discussed, which can alleviate the most challenging drawback of COFs for these applications. Finally, the major challenges and future trends of COF materials in electrochemical applications are outlined.
C. Zhong, Yida Deng, Wenbin Hu et al.
Chemical Society Reviews · 2015
Electrolytes have been identified as some of the most influential components in the performance of electrochemical supercapacitors (ESs), which include: electrical double-layer capacitors, pseudocapacitors and hybrid supercapacitors. This paper reviews recent progress in the research and development of ES electrolytes. The electrolytes are classified into several categories, including: aqueous, organic, ionic liquids, solid-state or quasi-solid-state, as well as redox-active electrolytes. Effects of electrolyte properties on ES performance are discussed in detail. The principles and methods of designing and optimizing electrolytes for ES performance and application are highlighted through a comprehensive analysis of the literature. Interaction among the electrolytes, electro-active materials and inactive components (current collectors, binders, and separators) is discussed. The challenges in producing high-performing electrolytes are analyzed. Several possible research directions to overcome these challenges are proposed for future efforts, with the main aim of improving ESs' energy density without sacrificing existing advantages (e.g., a high power density and a long cycle-life) (507 references).
Anoop Singh, Asha Sharma, Aamir Ahmed et al.
Biosensors · 2021
The electrochemical biosensors are a class of biosensors which convert biological information such as analyte concentration that is a biological recognition element (biochemical receptor) into current or voltage. Electrochemical biosensors depict propitious diagnostic technology which can detect biomarkers in body fluids such as sweat, blood, feces, or urine. Combinations of suitable immobilization techniques with effective transducers give rise to an efficient biosensor. They have been employed in the food industry, medical sciences, defense, studying plant biology, etc. While sensing complex structures and entities, a large data is obtained, and it becomes difficult to manually interpret all the data. Machine learning helps in interpreting large sensing data. In the case of biosensors, the presence of impurity affects the performance of the sensor and machine learning helps in removing signals obtained from the contaminants to obtain a high sensitivity. In this review, we discuss different types of biosensors along with their applications and the benefits of machine learning. This is followed by a discussion on the challenges, missing gaps in the knowledge, and solutions in the field of electrochemical biosensors. This review aims to serve as a valuable resource for scientists and engineers entering the interdisciplinary field of electrochemical biosensors. Furthermore, this review provides insight into the type of electrochemical biosensors, their applications, the importance of machine learning (ML) in biosensing, and challenges and future outlook.
Ben Zhang, Yijuan Zheng, Tian-Yi Ma et al.
Advanced Materials · 2021
Electrochemical water splitting has attracted significant attention as a key pathway for the development of renewable energy systems. Fabricating efficient electrocatalysts for these processes is intensely desired to reduce their overpotentials and facilitate practical applications. Recently, metal–organic framework (MOF) nanoarchitectures featuring ultrahigh surface areas, tunable nanostructures, and excellent porosities have emerged as promising materials for the development of highly active catalysts for electrochemical water splitting. Herein, the most pivotal advances in recent research on engineering MOF nanoarchitectures for efficient electrochemical water splitting are presented. First, the design of catalytic centers for MOF‐based/derived electrocatalysts is summarized and compared from the aspects of chemical composition optimization and structural functionalization at the atomic and molecular levels. Subsequently, the fast‐growing breakthroughs in catalytic activities, identification of highly active sites, and fundamental mechanisms are thoroughly discussed. Finally, a comprehensive commentary on the current primary challenges and future perspectives in water splitting and its commercialization for hydrogen production is provided. Hereby, new insights into the synthetic principles and electrocatalysis for designing MOF nanoarchitectures for the practical utilization of water splitting are offered, thus further promoting their future prosperity for a wide range of applications.
Song Jin, Zhimeng Hao, Kai Zhang et al.
Angewandte Chemie International Edition · 2021
Electrochemical carbon dioxide reduction reaction (CO2RR) provides an attractive approach to convert renewable electricity into fuels and feedstocks in the form of chemical bonds. Among the different CO2RR pathways, CO2 conversion to carbon monoxide (CO) is considered as one of the most promising candidate reactions in the chemical industry due to its high technologically and economically feasibility. Integrating catalyst and electrolyte design with understanding of catalytic mechanism will yield scientific insights and promote this technology towards industrial implementation. Herein, we review recent advances and challenges for selective CO2 conversion to CO. The intelligent multidimensional catalyst and electrolyte engineering for CO2RR are comprehensively summarized. Furthermore, recent efforts on large-scale production of CO are provided so as to facilitate the industrialization of electrochemical CO2 reduction. To conclude, the remaining technological challenges and future direction of industrialized application of CO2RR to CO are put forward.
Hend S. Magar, Rabeay Y. A. Hassan, A. Mulchandani
Sensors · 2021
Electrochemical impedance spectroscopy (EIS) is a powerful technique used for the analysis of interfacial properties related to bio-recognition events occurring at the electrode surface, such as antibody–antigen recognition, substrate–enzyme interaction, or whole cell capturing. Thus, EIS could be exploited in several important biomedical diagnosis and environmental applications. However, the EIS is one of the most complex electrochemical methods, therefore, this review introduced the basic concepts and the theoretical background of the impedimetric technique along with the state of the art of the impedimetric biosensors and the impact of nanomaterials on the EIS performance. The use of nanomaterials such as nanoparticles, nanotubes, nanowires, and nanocomposites provided catalytic activity, enhanced sensing elements immobilization, promoted faster electron transfer, and increased reliability and accuracy of the reported EIS sensors. Thus, the EIS was used for the effective quantitative and qualitative detections of pathogens, DNA, cancer-associated biomarkers, etc. Through this review article, intensive literature review is provided to highlight the impact of nanomaterials on enhancing the analytical features of impedimetric biosensors.
Z. Yang, Jianlu Zhang, M. Kintner-Meyer et al.
Chemical Reviews · 2011
The is a comprehensive review on the needs and potential storage technologies for electrical grid that is expected to integrate significant levels of renewables. This review offers details of the technologies, in terms of needs, status, challenges and future R&d directions.
Mohammad A. Alkhadra, Xiao Su, M. Suss et al.
Chemical Reviews · 2022
Agricultural development, extensive industrialization, and rapid growth of the global population have inadvertently been accompanied by environmental pollution. Water pollution is exacerbated by the decreasing ability of traditional treatment methods to comply with tightening environmental standards. This review provides a comprehensive description of the principles and applications of electrochemical methods for water purification, ion separations, and energy conversion. Electrochemical methods have attractive features such as compact size, chemical selectivity, broad applicability, and reduced generation of secondary waste. Perhaps the greatest advantage of electrochemical methods, however, is that they remove contaminants directly from the water, while other technologies extract the water from the contaminants, which enables efficient removal of trace pollutants. The review begins with an overview of conventional electrochemical methods, which drive chemical or physical transformations via Faradaic reactions at electrodes, and proceeds to a detailed examination of the two primary mechanisms by which contaminants are separated in nondestructive electrochemical processes, namely electrokinetics and electrosorption. In these sections, special attention is given to emerging methods, such as shock electrodialysis and Faradaic electrosorption. Given the importance of generating clean, renewable energy, which may sometimes be combined with water purification, the review also discusses inverse methods of electrochemical energy conversion based on reverse electrosorption, electrowetting, and electrokinetic phenomena. The review concludes with a discussion of technology comparisons, remaining challenges, and potential innovations for the field such as process intensification and technoeconomic optimization.
Kui Fan, Wenfu Xie, Jinze Li et al.
Nature Communications · 2022
Electrochemical nitrate reduction to ammonia is a promising alternative strategy to the traditional Haber-Bosch process but suffers from a low Faradaic efficiency and limited ammonia yield due to the sluggish multi-electron/proton-involved steps. Herein, we report a typical hollow cobalt phosphide nanosphere electrocatalyst assembled on a self-supported carbon nanosheet array synthesized with a confinement strategy that exhibits an extremely high ammonia yield rate of 8.47 mmol h−1 cm−2 through nitrate reduction reaction, which is highly superior to previously reported values to our knowledge. In situ experiments and theoretical investigations reveal that the dynamic equilibrium between the generation of active hydrogen on cobalt phosphide and its timely consumption by nitrogen intermediates leads to a superior ammonia yield with a high Faradaic efficiency. This unique insight based on active hydrogen equilibrium provides new opportunities for large-scale ammonia production through electrochemical techniques and can be further used for carbon dioxide capture. While electrochemical conversion of nitrate to ammonia offers a renewable means to remediate waste compounds, it is challenging to achieve selective catalysis. Here, authors demonstrate a strategy to improve electrocatalytic ammonia production using cobalt phosphide on carbon nanosheet arrays.
Jaya Baranwal, Brajesh Barse, G. Gatto et al.
Chemosensors · 2022
The world of sensors is diverse and is advancing at a rapid pace due to the fact of its high demand and constant technological improvements. Electrochemical sensors provide a low-cost and convenient solution for the detection of variable analytes and are widely utilized in agriculture, food, and oil industries as well as in environmental and biomedical applications. The popularity of electrochemical sensing stems from two main advantages: the variability of the reporting signals, such as the voltage, current, overall power output, or electrochemical impedance, and the low theoretical detection limits that originate from the differences in the Faradaic and nonFaradaic currents. This review article attempts to cover the latest advances and applications of electrochemical sensors in different industries. The role of nanomaterials in electrochemical sensor research and advancements is also examined. We believe the information presented here will encourage further efforts on the understanding and progress of electrochemical sensors.
John Wang, J. Polleux, James Lim et al.
The Journal of Physical Chemistry C · 2007
The advantages in using nanostructured materials for electrochemical energy storage have largely focused on the benefits associated with short path lengths. In this paper, we consider another contribution, that of the capacitive effects, which become increasingly important at nanoscale dimensions. Nanocrystalline TiO2 (anatase) was studied over a dimensional regime where both capacitive and lithium intercalation processes contribute to the total stored charge. An analysis of the voltammetric sweep data was used to distinguish between the amount of charge stored by these two processes. At particle sizes below 10 nm, capacitive contributions became increasingly important, leading to greater amounts of total stored charge (gravimetrically normalized) with decreasing TiO2 particle size. The area normalized capacitance was determined to be well above 100 μF/cm2, confirming that the capacitive contribution was pseudocapacitive in nature. Moreover, reducing the particle size to the nanoscale regime led to faster...
H. M. Saleh, Amal I. Hassan
Sustainability · 2023
Nanomaterials have gained significant attention as a remarkable class of materials due to their unique properties and the fact that they encompass a wide range of samples with at least one dimension ranging from 1 to 100 nm. The deliberate design of nanoparticles enables the achievement of extremely large surface areas. In the field of cost-effective electrochemical devices for energy storage and conversion applications, nanomaterials have emerged as a key area of research. Their exceptional physical and chemical properties have led to extensive investigations aimed at improving the performance and cost-effectiveness of electrochemical devices, including batteries, supercapacitors, and fuel cells. The continuous development and enhancement of these high-performance materials are driven by the demand for enhanced productivity, connectivity, and sustainability at a reduced cost. This review focuses on the electrochemical performance of electrodes, energy storage, and electrochemical sensors (ES) based on nanotechnology. It discusses the application of nanotechnology in electrochemistry for water purification and the fate of substances in water, while also introducing green nanotechnology and cost-effective, high-fidelity product creation through electrochemical methods. The study emphasizes the synthesis of novel nanomaterials, such as metal–organic frameworks (MOFs), covalent organic frameworks (COFs), and MXenes, with applications in electrochemical devices. Furthermore, it explores the integration of nanostructures with electrochemical systems in economically significant and future applications, along with the challenges faced by nanotechnology-based industries. The paper also explores the interplay between nanomaterials and biosensors, which play a vital role in electrochemical devices. Overall, this review provides a comprehensive overview of the significance of nanomaterials in the development of cost-effective electrochemical devices for energy storage and conversion. It highlights the need for further research in this rapidly evolving field and serves as a valuable resource for researchers and engineers interested in the latest advancements in nanomaterials for electrochemical devices.
L. Canham
Applied Physics Letters · 1990
Indirect evidence is presented that free‐standing Si quantum wires can be fabricated without the use of epitaxial deposition or lithography. The novel approach uses electrochemical and chemical dissolution steps to define networks of isolated wires out of bulk wafers. Mesoporous Si layers of high porosity exhibit visible (red) photoluminescence at room temperature, observable with the naked eye under <1 mW unfocused (<0.1 W cm−2) green or blue laser line excitation. This is attributed to dramatic two‐dimensional quantum size effects which can produce emission far above the band gap of bulk crystalline Si.