Research on the electrocatalytic reduction of CO2 by microorganisms with a nano-titanium carburizing electrode

Abstract

The reduction of CO₂ to organics using microbial electrosynthesis (MES) is currently a popular research direction in the environmental field. In this study, we evaluated the effect of the electrode material on the production of organics from CO₂ in microbial electrosynthesis with a mixed-culture biocathode. The electrode material is an important factor influencing electron transfer, since it directly affects the efficiency of CO₂ reduction. In this study, we compared the performance of a graphite electrode and a metal-based carbon hybrid material electrode for the electro-reduction of CO_2. The cathode potential was set to -0.8 V (vs Ag/AgCl). When the cathode material was changed from a graphite electrode to a nano-titanium carburizing electrode, the current density of MES increased from 1.66 ± 0.2 A·m^-2 to 2.75 ± 0.2 A·m^-2, acetate accumulation increased from 127 mg/L to 234 mg/L, butyrate accumulation increased from 46 mg/L to 86.5 mg/L, and the total electron recovery of MES increased to nearly 70%. The results show that improving electrode performance can effectively improve the efficiency of MES for reducing CO₂. Metal-based carbon hybrid materials have good biological affinity and stability and also have good electrochemical performance.

Keywords: Microbial electrosynthesis; Nano-titanium carburizing electrode; Reduce carbon dioxide.