Cocatalyst-modified In2S3 photocatalysts for C–N coupling of amines integrated with H2 evolution†

Photocatalytic hydrogen (H₂) production coupled with selective oxidation of organic compounds into high-value-added organic intermediates has expansive prospects in the utilization and transformation of solar energy, which meets the development requirements of green chemistry. In this work, high-efficiency hole cocatalyst PdS-decorated In₂S₃ flower-like microspheres are fabricated for the effective visible-light-driven C–N coupling of amines to imines coupled with H₂ evolution. Owing to the establishment of the internal electric field, which further boosts the transfer of photoexcited holes to PdS, PdS–In₂S₃ exhibits distinctly enhanced photocatalytic redox performance, which is 39.8 times higher for H₂ and 14.3 times higher for N-benzylidenebenzylamine than that of the blank In₂S₃, along with high selectivity and stability. Furthermore, the practicability of dehydrogenation coupling of various aromatic amines to the corresponding C–N coupling products on PdS–In₂S₃ has been demonstrated and a plausible reaction mechanism has been proposed. This work is anticipated to stimulate further interest in establishing an innovative photoredox platform for selective organic synthesis coupled with H₂ evolution in a green and sustainable way.

Keywords: In₂S₃; Photoredox dual reaction; Hydrogen evolution; Visible light; Hole cocatalyst.