Self-assembly of graphene oxide and Shewanella oneidensis MR-1 formed a conductive bio-abiotic composite for enhancing microbial electrosynthesis performance

Microbial electrosynthesis (MES) is an attractive technology for converting CO₂ into chemicals. In this technique, electrons are acquired either directly or indirectly through H₂ in the cathode. Shewanella oneidensis MR-1 can perform hydrogen evolution reaction via reverse electron transfer at the cathode. In this study, the self-assembly of graphene oxide and S. oneidensis MR-1 formed a conductive bio-abiotic composite as a cathode for MES with Clostridium ljungdahlii, obtaining more biocatalysts for hydrogen evolution and enhancing electron transfer rate. The average H₂ production rate with the conductive bio-abiotic composite was 41.51 ± 2.54 × 10² mol d⁻¹, while the undecorated carbon felt was 12.96 ± 1.09 × 10² mol d⁻¹. Consequently, acetate and butyrate yields were 0.18 g L⁻¹ d⁻¹ and 0.07 g L⁻¹ d⁻¹, which increased by 2.1 and 1.7 times those of the control, respectively. This work provides new opportunities for constructing a highly efficient cathode via biotic-abiotic hybrid composite for improving MES performance.