Sn promotes formate production to enhance microbial electrosynthesis of acetate via indirect electron transport

Microbial electrosynthesis (MES) is a carbon dioxide conversion technology in which a microbial catalyst obtains electrons through an electrode as a driving force to reduce CO2 to multi-carbon organic matter. In this study, Sn-modified carbon felts were prepared by electrodeposition at different durations (30, 50, and 70 min). The presence of Sn provides formate as an electron donor for the MES system, which can accelerate the indirect electron transfer rate between microorganisms and electrodes, thus improving the yield of acetate. The result showed that the MES with Sn-modified cathode (70 min) obtained the highest acetate produce rate (0.32 g L-1 d-1) at -1.3 V Ag/AgCl, which was about twice that of the control group and three times of the hydrogen evolution catalyst CoP. At the same time, scanning electron microscopy and microbial community analysis showed that the Sn catalyst was beneficial to the growth of biofilm on the cathode and increased the accumu-lation of Acetobacterium. This study provides a promising strategy for improving MES efficiency by enhancing formate-mediated electron transport rate.

Automated summary

Microbial electrosynthesis (MES) is a carbon dioxide conversion technology that utilizes a microbial catalyst to reduce CO2 to organic matter using electrons obtained from an electrode. This study demonstrates that Sn-modified carbon felts can enhance electron transfer rate and improve acetate yield in the MES system by providing formate as an electron donor. The results show that the MES with Sn-modified cathode achieved the highest acetate production rate compared to the control group and hydrogen evolution catalyst CoP. Scanning electron microscopy and microbial community analysis confirm that the Sn catalyst promotes biofilm growth and accumulation of Acetobacterium on the cathode.