Dissociation-Assembly-Carbonization: A Strategy for Constructing Indium Sulfide Photocatalysts with Increased Reactive Sites and Spatial Charge Separation

Sufficient surface reaction sites and a high separation of photogenerated carriers are two important guarantees for photocatalytic reactions. In this work, using a layered coordination compound In(pydc)2 as a precursor, through the dissociation-assembly-carbonization process, a three-dimensional (3D) complex hierarchical structure assembled by uniform N,O-codoped carbon-encapsulated In2S3 ultrathin nanosheets (N,O–C/In2S3 DP) has been obtained. The unique 3D hierarchical structure can expose the surface-active sites of ultrathin nanosheets to the greatest extent, which provides enough surface sites for photocatalytic reactions. The coated N,O-codoped carbon layer can not only realize the spatial separation of photogenerated electrons and holes but also promote the activation for organic reactants. In addition, the multielectron codoping of N and O in a carbon layer is conducive to the generation of superoxide radicals (O2·–), which is an important active group in a photocatalytic organic selective oxidation reaction. Thus, N,O–C/In2S3 DP exhibits good catalytic activity for the selective oxidation of sulfides to sulfoxides under the irradiation of various light sources (blue light, green light, and yellow light). This study provides a design and synthesis strategy (dissociation-assembly-carbonization) for constructing a suitable structure with a specific composition as excellent photocatalysts in the future.