Band structure engineering design of g-C3N4/ZnS/SnS2 ternary heterojunction visible-light photocatalyst with ZnS as electron transport buffer material

Abstract

Semiconductor heterojunction represents a family of promising photocatalysts for visible-light photocatalysis. In this work, a novel ternary g-C3N4/ZnS/SnS2 heterostructure has been designed and synthesized by a facile one-step hydrothermal method. The obtained ternary g-C3N4/ZnS/SnS2 heterostructures exhibited high photocatalytic activity in photodegradation of organic pollutants and photocurrent response irradiated by 410 nm LED light. The results demonstrated that the formation of the heterostructures can much improve the excellent photocatalytic activity if the lattice and energy level matching among the three semiconductors be satisfied, which causes efficient separation of photoinduced carriers, resulting in the high photodegradation of methylene blue (MB). As a result, the highest apparent rate constant Kapp of g-C3N4/ZnS/SnS2 hybrid is 0.148 min−1, which is 8.74, 3.22 and 37.01 times as high as that of pristine g-C3N4, SnS2 and ZnS, respectively.