Interfacial chemical bond modulated Bi19S27Br3/g-C3N4 Z-scheme heterojunction for enhanced photocatalytic CO2 conversion

Abstract

Direct Z-scheme heterojunction can primely facilitate separation efficiency of the photogenerated carriers and maximize the redox ability of as-prepared photocatalyst, which has been regarded as one of the promising strategies to increase photocatalytic CO2 conversion efficiency. Herein, a novel interfacial C-S bond modulated Z-scheme heterojunction Bi19S27Br3/g-C3N4 composite is constructed to accelerate the photogenerated electron transfer from g-C3N4 to Bi19S27Br3, offering much more excited reductive electrons to the surface of Bi19S27Br3 where owns lower CO2 adsorption energy, which is more conducive to CO2 reduction conversion. Without adding sacrificial agent or photosensitizer, the photocatalytic CO2 conversion to CO yield of Bi19S27Br3/g-C3N4 reaches up to 12.87 μmol g−1 h−1, which is 5 and 4-fold of Bi19S27Br3 and g-C3N4, respectively. This study provides the new insight in precisely tailoring photogenerated charge separation direction by establishing chemical bond in direct Z-scheme structure for CO2 photoreduction.