FeO/granular activated carbon as an efficient three-dimensional electrode to enhance the microbial electrosynthesis of acetate from CO.

Microbial electrosynthesis (MES) allows the transformation of CO into value-added products by coupling with renewable energy. The enhancement in the microbial activity and electron transfer rate a new electrode modification method is essential for developing MES. Here, three groups of granular activated carbon decorated by FeO (FeO/GAC) with mass fractions of 23%, 38% and 50% were prepared and compared with bare GAC. The volumetric acetate production rate of MES with FeO/GAC-38% was the highest (0.171 g L d), which was 1.4 times higher that of the control (bare GAC), and the final acetate concentration reached 5.14 g L within 30 days. Linear sweep voltammetry and microbial community analyses suggested that FeO/GAC facilitates extracellular electron transfer and improves the enrichment of electrochemically active bacteria. FeO/GAC is an effective three-dimensional electrode material that enhances biofilm activity on GAC and improves MES efficiency.