▎ 摘　　要

Copper ferrite/reduced graphene oxide (CF/rGO) nanocomposites (NCs) was synthesized using the biocombustion method and applied as a cathode catalyst in the microbial reduction of CO2 to volatile fatty acids (VFAs) in a single chamber microbial electrosynthesis system (MES). The synthesized NCs exhibited a porous network-like structure with a high surface area of CF/rGO (158.22 m(2)/g), which was 224 folds higher than that of CF. The Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) analysis for CF/rGO/Carbon cloth (Cc) revealed a high reduction current density of -7.3 A/m(2) and a low charge transfer resistance of 2.8 The isobutyrate and acetate in MES-2 (Cu/rGO/Cc) were produced at 35.37 g/m(2)/d, which was 1.53 folds higher than that of MES-1 (bare Cc: 23.10 g/m(2)/d). The columbic efficiency (77.78%) and total VFA concentration (1941.13 +/- 83 mg COD/L) were noted to be 1.97 and 1.6 folds higher for MES-2 than MES-1, respectively. The Tafel plot drawn from the CV curves exhibited an exchange current density value of MES-2 that was 3.46 A/m(2), and this value was 1.19 and 33.92 folds higher than that of MES-1 and abiotic CF/rGO/Cc, respectively. Field emission scanning electron microscopy (FESEM) observations revealed enhanced rod-shaped bacteria had grown on the cathode suggesting excellent biocompatible and multi-length scale porosity of CF/rGO catalysts for enhanced colonization of microbes. The phyla Proteobacteria (Be taproteobacteria), Bacteroidetes, and Firmicutes were highly abundant as the dominant microbial communities on the cathode, which might played a major role in bioelectroche mical CO2 reduction to VFAs. The results from this study clearly demonstrate that the CF/rGO/Cc electrode could serve as a conductive element between microbes and bactericidal electrodes with excellent electrochemical properties to enable performance of the MES. (C) 2021 Elsevier B.V. All rights reserved.