Photocatalytic β-In2S3 nanoflowers synthesized by thermal assembly of In2S3 nanosheets

Three-dimensional (3D) β-In2S3 offers photocatalytic advantages by virtue of its strong and broadband optical absorption resulting from its large effective surface area and a high density of sulfur vacancies. However, the use of surfactants and reducing agents complicates the synthesis process and causes undesirable agglomeration while forming the 3D structures, degrading the photocatalytic efficiency of 3D In2S3. Here we have prepared the surfactant-free In2S3 nanoflowers by the thermal assembly of two-dimensional (2D) In2S3 nanosheets and achieved a substantial enhancement of the optical absorption and the tunable bandgap narrowing. We show that owing to the intrinsic structure of our In2S3 nanoflowers that preserves the unit geometry of 2D In2S3 nanosheets, the rate of photocatalytic performance was enhanced by 200% just by the post-annealing process. The facile method used to prepare In2S3 nanoflowers expedites the practical application of 3D In2S3 for energy and environmental purposes.