Ag and Cu Nanoparticles Synergistically Enhance Photocatalytic CO2 Reduction Activity of B Phase TiO2

Considering that CO2 is a harmful greenhouse gas, the effective conversion of this compound to high-value hydrocarbons is highly desirable, but also challenging. Herein, we synthesize a series of Cu- and Ag-modified TiO2 (B phase) photocatalysts, and we analyze their efficiency in catalyzing the photoreduction of CO2 in the presence of H2O and simulated solar irradiation. The obtained results show that the TiO2(B) catalyst modified with 1% Ag and 0.5% Cu has the best photoreduction performance, with CO and CH4 yields of 860 and 410 μmol/g, respectively, after for 3 h of reaction. Based on CO2-TPD testing, Cu enhances the photocatalytic activity of TiO2(B) by adsorbing and activating CO2. Meanwhile, the Ag nanoparticles increase the absorption of visible light through surface plasmonic resonance effect (SPR), and they transfer electrons to the TiO2(B) nanosheets. The transferred electrons migrate to the Cu particles where they reduce the adsorbed and activated CO2. This study provides an effective method for improving the photocatalytic CO2 reduction performance of TiO2(B)-based catalysts.