The heterojunction between 3D ordered macroporous TiO2 and MoS2 nanosheets for enhancing visible-light driven CO2 reduction

Abstract

The photocatalytic CO2 and H2O conversion into CO and hydrocarbons over the semiconductors catalysts is an effective way to alleviate environmental pollution and resource shortage currently. Herein, three-dimensional ordered macroporous (3DOM) TiO2-supported two-dimensional layered MoS2 (MoS2/3DOM-TiO2) as two isolated photochemical systems were proposed to form heterojunction structure. The diffuse reflection of photonic crystal microstructure can raise the adsorption efficiency of visible light. The formation of TiO2-MoS2 heterojunction is favorable to the enhancing separation efficiency of photoexcitation electron and hole pairs. The binary MoS2/3DOM-TiO2 photocatalyst shows the higher catalytic performance for visible-light driven reduction of CO2 in the range of 420−900 nm. MoS2/3DOM-TiO2-1.5 photocatalyst shows the highest maximum formation yields of CO (22.6 μmol g-1) as well as CH4 (11.6 μmol g-1) products during 8 h, then its apparent quantum efficiency value is 6.7 %, which is far higher than the photosynthesis efficiency of green plants. The heterojunction of MoS2/3DOM-TiO2 photocatalysts with enhancing light adsorption and electron-hole separation efficiency is expected to provide more extensive reference for the evolution of high-efficient photocatalyst for CO2 conversion.