Cathode materials in microbial electrosynthesis systems for carbon dioxide reduction: recent progress and perspectives

Abstract

Microbial electrosynthesis (MES) is an emerging technology that enables the synthesis of value-added chemicals from carbon dioxide (CO2) or inorganic carbon compounds by coupling renewable electricity to microbial metabolism. However, MES still faces challenges in achieving high production of value-added chemicals due to the limited extracellular electron transfer efficiency at the biotic-abiotic interfaces. To overcome this bottleneck, it is crucial to develop novel cathodes and modified materials. This review systematically summarizes recent advancements in cathode materials in the field of electrocatalyst-assisted and photocatalyst-assisted MES. The effects of various material types are further investigated by comparing metal-free and metal materials and photocatalyst materials of different semiconductor types. Additionally, the review introduces the maximum production rate of value-added chemicals and conversion efficiency achieved by these cathode materials while highlighting the advantages and disadvantages of different material types. To the best of our knowledge, in electrocatalyst-assisted systems, the maximum CH4 yield on graphene aerogel/polypyrrole cathode achieved 1,672 mmol m-2 d-1, and the maximum Faraday efficiency (FE) of CH4 reached up to 97.5% on graphite plate. Meanwhile, the maximum acetate yield achieved 1,330 g m-2 d-1 with CO2 conversion efficiency into acetate close to 100% on carbon nanotube cathodes. In photocatalyst-assisted systems, the maximum acetate yield could reach 0.51 g L-1 d-1 with the coulombic efficiency of 96% on the MnFe2O4/g-C3N4 photocathode. Finally, prospects for future development and practical applications of MES are discussed, offering theoretical guidance for the fabrication of cathode materials that can improve production efficiency and reduce energy input.

Electrochemical Reduction of CO2 by the SnS| PTFE| Pt Surface in an Aqueous Imidazole Medium: Catalysis and Kinetics

“…Several reductive pathways leading to distinct oxidation states of carbon (from C 2 O 4 2– to CH 4 ) have been documented in the scientific literature. − Previous studies have shown that transition metal and p-block metal electrodes, such as Au, Ag, Cu, Pd, Pt, In, Sn, Hg, and Pb, are attractive candidates for CO 2 reduction reaction. − Among them, Cu is the only metal catalyst that was found to produce considerable C1–C3 hydrocarbon products . Koper et al reported that bimetallic Pd–Pt alloy nanoparticles exhibit a very low onset potential and a high Faradaic efficiency for the selective reduction of CO 2 to HCOOH .…”