Ag quantum dots modified hierarchically porous and defective TiO2 nanoparticles for improved photocatalytic CO2 reduction

Photocatalytic reduction of CO2 into high added-value chemical products has received special attention. Herein, we designed a novel hierarchically porous and defective TiO2 modified by Ag quantum dots via a hydrothermal process assisted with organic surfactant and subsequently in-situ photodeposition method. The obtained Ag quantum dots modified TiO2 (Ag/TiO2) shows excellent and stable photocatalytic activity in CO2 reduction. In addition, the competing H2 evolution can be completely suppressed. The super photocatalytic activity can be ascribed to the design of hierarchically porous, the intrinsic defects in TiO2, the localized surface plasmon resonance of Ag and the synergetic effect between Ag quantum dots and defective TiO2, which jointly improves the CO2 adsorption performance, enhances visible light absorption capacity and accelerates the separation of photogenerated charges. This work may provide a strategy to design and synthesis defective and hierarchically porous metal oxides for photocatalytic CO2 reduction.