초록
<P><B>Abstract</B></P> <P>Each carbon-based material, due to the discrepancy in critical properties, has distinct capability to enrich electroactive microbes able to electrosynthesize methane from CO<SUB>2</SUB>. To optimize electromethanogenesis process, this study physically prepared and examined several carbon-based cathode materials: carbon stick (CS), CS twined by Ti wire (CS-Ti) or covered with carbon fiber (CS-CF), graphite felt (CS-GF) and carbon cloth (CS-CC). CS-GF electrode had constantly stable methane production (75.8 mL/L/d at −0.9 V vs. Ag/AgCl) while CS-CC showed a suppressed performance over time caused by the desposition of inorganic shell. Electrode material properties affected biofilms growth, cell-electrode contact behaviors and electron exchange. Methane formation with CS-CC biocathode was H<SUB>2</SUB>-concnetration dependent; CS-GF cathode possessed high antifouling properties and extensive space, enriching the microorganisms capable of catalyzing electromethanogenesis through more efficient non-H<SUB>2</SUB> route. This study re-interpreted the application potentials of carbon-based materials in CO<SUB>2</SUB> electroreduction and electrofuel recovery, providing valuable guidance for materials’ selection.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Five different carbon-based cathode materials were physically prepared and examined. </LI> <LI> Carbon stick + graphite felt assembly (CS-GF) had the highest methane production. </LI> <LI> Material properties affected microbe growth, contact behaviors and electron exchange. </LI> <LI> CS-GF facilitated the enrichment of microorganisms to catalyze CO<SUB>2</SUB> via direct electron transfer. </LI> <LI> Carbon stick + carbon cloth (CS-CC) biocathode was H<SUB>2</SUB>-concnetration dependent. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>