Synchronistic embedding of oxygen vacancy and Ag nanoparticles into potholed TiO2 nanoparticles-assembly for collaboratively promoting photocatalytic CO2 reduction

Photocatalytic CO2 reduction offers a potential to produce clean and renewable fuels as well as reduce massive emissions of CO2 by utilizing solar energy. The inhibited charge recombination and fertile surface reactive sites play vital roles in determining the photocatalytic performance and products selectivity in CO2 reduction reaction. Herein, the Ag/TiO2-x hybrid by synchronistic introduction of oxygen vacancy and Ag nanoparticles into SiO2 spheres-templated potholed TiO2 assembly with nanoparticles is constructed for photocatalytic CO2 conversion. The Schottky junction between oxygen vacancy TiO2-x and Ag particles provides synergistic enhancement of solar light utilization, photo-induced charge separation and migration process, which is of significance in the promoted CO2 photo-conversion. Indeed, the CH4 yield of oxygen vacancy TiO2-x (1.56 μmol/g/h) is more than 3 times as high as the TiO2 (0.47 μmol/g/h), while the as-synthesized Ag/TiO2-x hybrids show an enhancement of photocatalytic CO2 reduction into CH4 and CO. Among them, the Ag/TiO2-x-10% hybrid has the best photocatalytic performance, and it shows significantly superior CH4 (8.61 μmol/g/h) and CO (2.27 μmol/g/h) yields to that of pure TiO2-x and TiO2.