Localized surface plasmon resonance effect of bismuth nanoparticles in Bi/ TiO2 catalysts for boosting visible light-driven CO2 reduction to CH4

Herein, the photocatalysts of metallic Bi-modified TiO2 microsphere (namely BTO) were synthesized by one-pot solvothermal method. The localized surface plasmon resonance (LSPR) effect of introduced metallic Bi nanoparticles is beneficial to improve the absorption efficiency for visible light, and its surface hot electrons can donate to the valence band of TiO2 for boosting the separation efficiency of light generated electron-hole pairs. BTO catalysts exhibit the super catalytic activity for visible light-driven CO2 reduction with H2O to CH4. The formation amount and selectivity of CH4 product over BTO-2 catalyst are 49.12 mu mol g-1 and 85.48 % for 4 h, respectively. Based on the results of in-situ DRIFTS and density functional theory calculation, the mechanism for photocatalytic CO2 reduction is proposed: the visible light-driven LSPR effect on BTO catalyst can boost the key step of CO2* -to-HCO* for promoting selective generation of CH4 product. It inspires the design of efficient photocatalysts for CO2 conversion.