Photocatalytic H2 evolution integrated with selective amines oxidation promoted by NiS2 decorated CdS nanosheets.

[Display omitted] • Nickel disulfide decorated CdS nanosheets (NiS 2 /CdS) are synthesized. • NiS 2 can serve as the active sites for hydrogen evolution reaction and dehydrogenation reaction. • The integrated photocatalytic redox cycles for H 2 production and imine synthesis are achieved on NiS 2 /CdS. Photocatalytic hydrogen (H 2) evolution integrated with selective oxidation to produce fine chemicals is a promising strategy for solar energy conversion and storage; however, the efficiency of such coupled photocatalytic redox cycles is greatly limited by the poor surface kinetics of hydrogen evolution reaction (HER) and/or dehydrogenation reaction (DHR) on heterogenous photocatalysts. Herein, we demonstrate that the immobilization of ultrafine nickel disulfide (NiS 2) nanoparticles on CdS nanosheets (NiS 2 /CdS) is a simple yet efficient approach to kinetic improve the surface redox reactions for H 2 production and dehydrogenative coupling of amines to imines. The NiS 2 nanoparticles loaded on CdS not only function as the HER active sites to speed up charge separation and to boost H 2 release, but also enhance the adsorption of amines to facilitate the dissociation of C-H and N-H bonds to form aldimines intermediates, which are readily coupled with other amines to afford a high selectivity toward imine synthesis. Benefiting from such unique bifunctional catalytic behavior of NiS 2 in proton (H+) reduction and substrate activation, NiS 2 /CdS exhibits a remarkable enhanced photocatalytic performance toward simultaneous production of H 2 and imines. The apparent quantum efficiency (AQE) at 420 nm is calculated to be 54.7%. This strategy using bifunctional cocatalysts to kinetic improve the surface redox reactions will have broad implications in the development of high-performance photocatalysts for integrated production of solar hydrogen and value-added solar chemicals. [ABSTRACT FROM AUTHOR]