Au@ZnS core–shell nanoparticles decorated 3D hierarchical porous TiO2 photocatalysts for visible-light-driven CO2 reduction into CH4

Abstract

Hereby, the core–shell structured Au@ZnS nanoparticles were precipitated on three-dimensionally ordered macro-mesoporous TiO2 (Au@ZnS/3DOMm-TiO2) by GBMR/P method. The slow photon effect of 3DOM structure leads to increase the light trapping and absorption efficiency. The hierarchical porous structure improves the specific surface area of the carrier, providing a larger internal void for desorption of reaction products and additional activation sites for the CO2 reduction. In the all-solid Z-scheme system, electrons are transferred along the direction from TiO2 to Au and finally to the surface of ZnS is realized to participate in the reaction of CO2 reduction. Under irradiation of visible light, ternary Au@ZnS/3DOMm-TiO2-2 catalyst exhibits the highest catalytic activity for CO2 photoreduction with H2O, i.e., the formation rate and selectivity of CH4 product is 33.2 µmol g-1h−1 and 91.5 %, respectively. The design of Z-scheme heterojunctions on 3D macro-mesoporous oxide surfaces are expected to expand new ideas for the preparation of efficient photocatalysts.