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

Abstract

In2S3 (β-In2S3), semiconducting chalcogenide with desirable physicochemical properties, has fascinated researchers in photoelectrochemistry. Because of its wide band gap, In2S3 can utilize solar energy below 600 nm. However, rapid photogenerated electron–hole recombination and low quantum efficiency have limited the practical application of In2S3 in this field. In a two-step in situ hydrothermal process we introduced a narrow band gap semiconductor (ReS2) below the In2S3 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 In2S3, and the photoelectrochemical performance is approximately three times better than that of pristine In2S3 at 1.23 V versus a reversible hydrogen electrode under sunlight. This method therefore provides a new prospect for optimizing the performance of In2S3 and applying the novel heterojunction.