Construction of a novel direct Z-scheme heterostructure consisting of ReS2 nanoflowers and In2S3 nanohoneycombs for improving photoelectrochemical performance

Abstract In 2 S 3 (β-In 2 S 3 ), semiconducting chalcogenide with desirable physicochemical properties, has fascinated researchers in photoelectrochemistry. Because of its wide band gap, In 2 S 3 can utilize solar energy below 600 nm. However, rapid photogenerated electron–hole recombination and low quantum efficiency have limited the practical application of In 2 S 3 in this field. In a two-step in situ hydrothermal process we introduced a narrow band gap semiconductor (ReS 2 ) below the In 2 S 3 and constructed a direct Z-scheme heterostructure with nanoflower and honeycomb morphology. The formation of a direct Z-scheme heterostructure and coordination of the trap-like structure of the composite give a wider absorption range, higher migration and separation efficiency, and faster interfacial transfer speed than for pristine In 2 S 3 , and the photoelectrochemical performance is approximately three times better than that of pristine In 2 S 3 at 1.23 V versus a reversible hydrogen electrode under sunlight. This method therefore provides a new prospect for optimizing the performance of In 2 S 3 and applying the novel heterojunction.