All-solid-state artificial Z-scheme porous g-C3N4/Sn2S3-DETA heterostructure photocatalyst with enhanced performance in photocatalytic CO2 reduction

Nowadays, the increasing CO2 emissions have attracted widespread attentions and it is necessary to reduce CO2 emissions to solve the global warming problem. So photocatalytic reduction of CO2 into chemical fuels is a promising strategy. Here, a Z-scheme porous g-C3N4/Sn2S3-diethylenetriamine (Pg-C3N4/Sn2S3-DETA) composite without an electron intermediary is designed. Photocatalytic performance of the as-fabricated samples is investigated on the basis of photocatalytic CO2 reduction (PCR) to form CH4 and CH3OH. We find that the Z-scheme heterostructure photocatalysts show a higher PCR performance than Pg-C3N4 and Sn2S3-DETA. An optimized Pg-C3N4/Sn2S3-DETA heterostructure sample displays high CH4 production rate of 4.84 μmol h−1 g−1 and CH3OH-production rate of 1.35 μmol h−1 g−1 with 5% Pg-C3N4 content. The superior PCR performance could be ascribed to the special structure of a direct Z-scheme Pg-C3N4/Sn2S3-DETA photocatalyst, which is beneficial to efficient separation of electron-hole pairs. Density functional theory (DFT) calculation further confirms the presence of direct Z-scheme mechanism. This Z-scheme heterostructure photocatalyst with superior performance may inaugurate the perspective on a new promising hierarchy of materials on CO2 photoreduction.