Photocatalytic imines synthesis integrated with H2 evolution over Ni doped Mn0.25Cd0.75S catalyst.

• The Ni doped Mn 0.25 Cd 0.75 S (MCS-Ni) photocatalysts have been well synthesized. • Dehydrocoupling of amines into imines integrated with H 2 evolution is performed in one photoredox cycle. • The photocatalytic mechanism is revealed for this bifunctional photoredox system. Photocatalytic selective organic transformations coupled with hydrogen (H 2) generation under anaerobic conditions is a promising alternative to tackle the challenges of global energy scarcity and green synthesis. In this work, we report the synthesis and application of Ni doped Mn 0.25 Cd 0.75 S (MCS-Ni) composites for efficient selective dehydrocoupling of amines into imines and H 2. The optimal MCS-Ni composite displays markedly enhanced activities for imines and H 2 generation, which are 7.9 and 11.5 times as high as those of pristine MCS, respectively. The Ni doping modulates the electronic structure of MCS, which improves the light-harvesting abilities and inhibits the recombination of photo-generated electron-hole pairs, thereby remarkably improving the photocatalytic performance of the MCS-Ni composite. Furthermore, the electron paramagnetic resonance (EPR) technique reveals that carbon centered radicals are the critical intermediates in the amine oxidation reaction. This work is promising to provide inspiration towards the rational construction of metal doped semiconductor composite photocatalysts with effective utilization of photo-generated electrons and holes for the coproduction of clean H 2 fuel and high-value added chemicals in a collaborative photoredox reaction. [Display omitted] [ABSTRACT FROM AUTHOR]