Engineering two-dimensional multilayer heterostructure of internal electric field to enhance CO2 photoreduction

Abstract

CO₂ photo reduction provides a feasible technique to solve climate issues and promote carbon neutrality. However, the efficiency of CO₂ photo reduction is severely depressed by the rapid recombination of photo generated carriers within photo catalysts, restricting the participation of electrons in the reduction process. In this study, we successfully construct a two-dimensional (2D) multilayer internal electric field (IEF) heterostructure by engineering the interface between NiAl-LDH and ZnV₂O₆ (ZNA). Driven by the IEF, the separation of photo generated electron-hole pairs is significantly enhanced, leading to the increased utilization efficiency of carriers for active sites. The best-performing sample of ZNA-2 achieves a highest CO yield of 695.8 μmol g⁻¹, approximately 30.5-fold higher than that of pristine ZnV₂O₆. Photo electrochemical measurement and density functional theory (DFT) calculation results reveal that the 2D-2D stacked structure generates multiple interlayer built-in electric fields, which are crucial for enhancing carrier separation and suppressing recombination. Adsorption energy and intermediate COOH* analysis reveal that ZNA-2 significantly lowers the adsorption energy of CO₂, promoting its stable adsorption and subsequent conversion. Moreover, the unique 2D multilayer IEF heterostructure greatly facilitates the formation of key intermediate COOH* and the desorption of CO during CO₂ photo reduction, leading to high CO activity and selectivity. The present work discloses the unprecedented potential of 2D multilayer IEF heterostructures for efficient CO₂ photo reduction, marking a significant advancement over conventional 2D counterparts.