Rich Indium-Vacancies In2S3 with Atomic p-n Homojunction for Boosting Photocatalytic Multifunctional Properties

Design and development of highly efficient photocatalytic materials are key to employ photocatalytic technology as a sound solution to energy and environment related challenges. This work aims to significantly boost photocatalytic activity through rich indium vacancies (V-In) In2S3 with atomic p-n homojunction through a one-pot preparation strategy. Positron annihilation spectroscopy and electron paramagnetic resonance reveal existence of V-In in the prepared photocatalysts. Mott-Schottky plots and surface photovoltage spectra prove rich V-In In2S3 can form atomic p-n homojunction. It is validated that p-n homojunction can effectively separate carriers combined with photoelectrochemical tests. V-In decreases carrier transport activation energy (CTAE) from 0.64 eV of V-In-poor In2S3 to 0.44 eV of V-In-rich In2S3. The special structure endows defective In2S3 with multifunctional photocatalysis properties, i.e., hydrogen production (872.7 mu mol g(-1) h(-1)), degradation of methyl orange (20 min, 97%), and reduction in heavy metal ions Cr(VI) (30 min, 98%) under simulated sunlight, which outperforms a variety of existing In2S3 composite catalysts. Therefore, such a compositional strategy and mechanistic study are expected to offer new insights for designing highly efficient photocatalysts through defect engineering.