Zeolitic imidazolate framework-8 modified cathode promotes microbial electrosynthesis from carbon dioxide

Abstract

Microbial electrosynthesis (MES) is an electrochemical reduction technology through which microorganisms attached to a cathode are driven by electricity to reduce carbon dioxide (CO2) into industrial chemicals. However, the limited contact time with biocatalysts affects the performance of MES because of low CO2 solubility. In this study, zeolitic imidazolate framework-8 (ZIF-8) particles with different pore diameters modified cathodes were prepared. Results showed that the ZIF-8 modified electrode obtained the maximum acetate production rate (0.13 g L−1 d−1), which was 1.4 times that of bare CF, and the accumulated acetate concentration reached 4.04 ± 0.1 g L−1 within 30 days. Brunauer–Emmett–Teller test and CO2 adsorption characteristic evaluation indicated that ZIF-8 had a high specific surface area and an excellent CO2 adsorption capacity. Scanning electron microscopy and microbial community analysis revealed that ZIF-8 modified electrodes were beneficial to biofilm formation and increased the enrichment of Acetobacterium and Arcobacter. Therefore, CO2-adsorbing materials modified electrodes are effective in improving the performance of MES.