Ameliorating the carrier dynamics behavior via plasmonic Ag-modified CuBi2O4 inverse opal for the efficient photoelectrocatalytic reduction of CO2 to CO

Low light absorption efficiency and short carrier diffusion length mainly restrict the use of CuBi2O4 as a photocathode for an efficient photoelectrocatalytic CO2 reduction reaction (PEC-CO2 RR). These inadequacies are alleviated by fabricating CuBi2O4 inverse opal photocathode modify with plasmonic Ag nanoparticles (CuBi2O4 IOs-Ag) by using a sacrificing template method. The CuBi2O4 IOs-Ag photocathode exhibits superior PEC-CO2 RR-to-CO performance with a Faraday efficiency (FE) of 92% at 0.2 V versus reversible hydrogen electrode, and this value is roughly 1.6 times that of the pristine CuBi2O4 thin film. Detail characterization and experiments reveal that the exceptional three-dimensional (3D) order structure simultaneously accelerates the mass transfer rates and enhances the light-harvesting efficiency. In addition, the introduction of Ag nanoparticles remarkably improves the surface charge distribution by forming an ohmic contact with CuBi2O4. Consequently, carrier recombination is efficiently inhibited, and the carrier dynamics behavior is improved. This work provides important insights into the design of high-performance photoelectrocatalytic systems for CO2 reduction by engineering the microstructure of catalysts with localized surface plasmon resonance effect.