Mo2C/N-doped 3D loofah sponge cathode promotes microbial electrosynthesis from carbon dioxide.

Microbial electrosynthesis (MES) is a promising technology through which carbon dioxide is converted into chemicals via bioelectrochemcal reaction. In this study, a natural loofah sponge (LS) was directly converted into a 3D macroporous carbon cathode through carbonization. The LS was codecorated with polydopamine and Mo 2 C (Mo 2 C/N-doped LS). Results revealed that the acetate production rate of MES with Mo 2 C/N-doped LS increased by 2.5 times compared with that of carbon felt. The maximum acetate concentration of 6.08 g L−1 and 64% of coulomb efficiency (CE) were obtained in MES with Mo 2 C/N-doped LS. Electrochemistry, scanning electron microscopy, and microbial community analyses showed that Mo 2 C/N-doped LS contributed to biofilm formation and improved the enrichment of electrochemically active bacteria. Thus, this study introduced a promising method for the fabrication of 3D cathodes with a high electrocatalytic activity from low-cost sustainable natural materials to improve MES efficiency. [Display omitted] • LS provided a high specific area for microbial attachment. • LS was widely available and could easily produce 3D electrodes for MES. • Mo 2 C/N-doped LS was beneficial to direct and indirect electron transfer rate. • The acetate production rate of Mo 2 C/N-doped LS increased by 2.5 times. • The maximum acetate concentration of 6.08 g L−1 and CE of 64% were obtained. [ABSTRACT FROM AUTHOR]