Electrodeposited Ni–Co–S nanosheets on nickel foam as bioelectrochemical cathodes for efficient H2 evolution.

High overpotential and soaring prices of the cathode electrode are the bottlenecks for the development of microbial electrolysis technology for hydrogen production. In this study, a novel one-step electrodeposition method has been attempted to fabricate electrodeposited cathodes in situ growth of Ni–Co–S, Ni–S, Co–S catalyst on nickel foam (NF) to reduce the overpotential of electrodes. Finally, a uniform nanosheet with a high specific surface area and more active sites is formed on the NF surface, resulting in a lower overpotential than plain NF. At 0.8 V, the Co–S/NF cathode produces a favorable 42% increase in hydrogen yield (0.68 m3·m−3·d−1), 40% upsurge in current density (10.6 mA/cm3) and 39% rise of cathodic recovery rate (58.0 ± 3.2%) than bare NF, followed by Ni–Co–S/NF and Ni–S/NF cathode. All the electrodeposited electrodes demonstrate enhanced current density and reduced electron losses, thereby achieving efficient hydrogen production. These innovative varieties of electrodes are highly advantageous as they are relatively inexpensive and easy to manufacture with great potential in reducing costs and further real time application in large scale. • The overpotential of nickel foam is greatly reduced by Ni/Co/S electrodeposition. • High hydrogen yield is achieved by Co–S/NF electrode in neutral condition. • Electrodeposited electrodes show high current density and low electron losses in MEC. [ABSTRACT FROM AUTHOR]