Indium-vacancy-rich In2S3/Ni@C photocatalyst with chemical bonds for producing hydrogen and benzylamine oxidation

Photocatalytic technology is considered a sound solution to exploit hydrogen energy. Currently, photocatalytic hydrogen production and organic synthesis under simulated sunlight simultaneously have enormous practical significance. Herein, we synthesized Ni@C metal nanoparticles cocatalyst to form a composite photocatalyst with Indium-vacancy-rich In2S3 by the electrostatic self-assembly method. The composite exhibited a hydrogen production rate of 3.52 mmol·g−1·h−1 and coupling of benzylamine 8.37 mmol·g−1·h−1. X-ray photoelectron spectroscopy and density functional theory explored the reaction process and mechanism. The charge density difference of the heterojunction surface revealed that the Ni@C interacted with the substrate via both electrostatic interaction and chemical bonds. This confirmed that the electrons rapidly transferred to the cocatalyst under the irradiation of visible light, which was conducive to the surface reduction reaction and greatly inhibited the photogenerated carrier recombination. Moreover, hydrogen adsorption energy further explained the synergistic effect of co-modification of the defect and the fact that noble-metal-free cocatalyst could improve photocatalytic efficiency. This work offers insights into the preparation of new types of photocatalysts which produce hydrogen and high-value chemicals in the future.