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 μmol 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.