Enhanced Photocurrent Generation From a Single‐Mediated Photo‐Bioelectrochemical Cell Using Wild‐Type Anabaena Variabilis Dispersed in Solution

Abstract

Abstract There is a growing interest in photosynthetic microorganisms for converting solar energy to electricity aiming at practical application. Despite extensive research, existing methods are suffered from limited photocurrent. Here we report that appreciable photocurrent can be generated in a photo‐bioelectrochemical cell (PBEC) where reduced graphene oxide‐coated ITO electrode is used as an anode and wild type cyanobacterium Anabaena variabilis as photo‐biocatalyst that oxidizes water by solar light. With A. variabilis dispersed in buffer and 1,4‐benzoquinone as a redox mediator, our PBEC produced photocurrent of 223 μA cm −2 at an applied voltage of 0.4 V vs. Ag/AgCl. Incident photon to current efficiencies of 0.50 % and 5.2 % were obtained with white and monochromatic light at 660 nm, respectively. A complete PBEC with Pt/C cathode produced P max of 13 μW cm −2 at 115 μA cm −2 . Methodology in this study can be extended to cover other cyanobacteria, electrode materials, and mediators to further enhance photocurrent and power density. Our results demonstrate the possibility of utilizing cyanobacteria that are ubiquitous in the environment as alternative energy sources.

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Identifiers

DOI

10.1002/celc.202001026

Journal

ChemElectroChem

Year

2020