Improved cathode for high efficient microbial-catalyzed reduction in microbial electrosynthesis cells

TLDR

Microbial electrosynthesis cells (MECs) enable microorganisms to exchange electrons directly with electrodes. The study aimed to develop a nickel‑nanowire‑anchored graphite cathode to enhance microbial‑catalyzed reduction in MECs. The porous nickel‑nanowire network on graphite increased interfacial area and biofilm interactions, improving electron transfer. The new cathode achieved a 2.3‑fold higher bio‑reduction rate, producing 282 mM day⁻¹ m⁻² acetate with 82 % electron recovery.

Abstract

Microbial electrosynthesis cells (MECs) are devices wherein microorganisms can electrochemically interact with electrodes, directly donating or accepting electrons from electrode surfaces. Here, we developed a novel cathode by using nickel nanowires anchored to graphite for the improvement of microbial-catalyzed reduction in MEC cathode chamber. This porous nickel-nanowire-network-coated graphite electrode increased the interfacial area and interfacial interactions between the cathode surface and the microbial biofilm. A 2.3 fold increase in bio-reduction rate over the untreated graphite was observed. Around 282 mM day−1 m−2 of acetate resulting from the bio-reduction of carbon dioxide by Sporomusa was produced with 82 ± 14% of the electrons consumed being recovered in acetate.