S-scheme efficient charge transfer interface between solid solution Mn0.5Cd0.5S and ultrathin 2D nanomaterial SnNb2O6 boosts photocatalytic CO2 reduction

Abstract

The rapid recombination of photogenerated carriers is one of the crucial factors restricting the photoreduction of CO2 into solar fuels. Therefore, designing an efficient photogenerated electron transfer photocatalysts system for efficient photoreduction of CO2 is of great importance. Herein, solid solution Mn0.5Cd0.5S (MCS) was designed to effectively suppress the problem of rapid recombination of electron-hole pairs in the pure metal sulfide itself. Furthermore, the formation of S-scheme effective interfacial contact with the ultrathin two-dimensional (2D) nanomaterial SnNb2O6 (SNO) by the hydrothermal synthesis method was able to realize the rapid separation and transfer of photogenerated carriers, optimize the reaction system path, increase the reaction redox potential, inhibit the recombination of electron-hole pairs itself, and improve the photoreduction performance and stability of the photocatalytic system. The photoreduction CO yield of 20 %MCS/SNO (31.72 μmol g−1 h−1) was 2 and 8 times higher than that of pure MCS (16.56 μmol g−1 h−1) and SNO (4.08 μmol g−1 h−1), respectively. The charge transfer mechanism between the solid solution MCS and the 2D ultrathin nanomaterial SNO interface was effectively demonstrated by XPS and DFT calculations. This study puts forward new insights and ideas for the effective combination of solid solutions and ultrathin 2D nanomaterials for photoreduction reactions.