Electromethanogenesis is an innovative technology utilizing a microbial electrochemical system to produce methane from CO2, in a bioelectrochemical power-to-gas concept (BEP2G). This study presents experimental test results of new and cost-effective carbonaceous materials for electrodes. The research aims to optimize electromethanogenesis processes at the laboratory scale under mesophilic conditions. During the experiments, hydrogenotrophic microorganisms (Family Metanobacteriaceae, Archaea domain) were selected from a mixed consortium taken from biogas digestate and inoculated into double-chamber bioelectrochemical systems.

The maximum amount of methane produced ranged from 0.3 to 0.8 mol/m²g (normalized to the cathode area) using carbon cloth electrodes. To enhance methane productivity, new electrode materials were studied, creating high-surface-area porous composites and investigating nitrogen-doped carbons doped with Cu and hydroxyapatite (Multicomposite Cu@/HAP/C) as chemical catalysts for CO2 reduction (CO2RR). A detailed description of the procedure for producing the Multicomposite Cu@/HAP/C is provided.