Photoelectroreduction CO2 to Ethanol Over BiFeO3 with Synergistic Effect of Self-Polarization and External Electric Field

The exploitation of semiconductor self-polarization is an effective mean of improving the efficiency of electron utilization. In this work, the synthesis of BiFeO3 (BFO) samples with varying photoelectric properties is achieved by modulating the concentration of KOH. The experimental results reveal that BFO-4 (4 m KOH) has excellent carrier efficiency. Interestingly enough, the ethanol yield of up to 7.05 mu mol cm(-2) h(-1) in the photoelectrocatalytic process, which is 1.4 times than that of single electrocatalysis. Based on the characterization data, the external electric field forms a multi-electric field coupling in the BFO (external electric field can enhance the self-polarization electric field), which enhances charge separation efficiency and facilitates surface reactions, and the CO2 reduction performance is improved. Finally, the free energy in the key step of C-C coupling on the surface of BiFeO3 is calculated by DFT. This study offers a valuable reference for the application of ferroelectric materials in the photoelectrocatalytic reduction of CO2 and the design of catalysts for C2+ products.