Dual cocatalysts decorated CdS nanoparticles for efficient dehydrocoupling of thiols into disulfides

Abstract

Simultaneously utilizing photoinduced electrons and holes to direct splitting of thiols into value-added disulfides and clean hydrogen (H2) fuels conforms the development standards of green chemistry. Herein, a cobalt phosphate (Co-Pi) and reduced graphene oxide (GR) modified CdS photocatalyst is synthesized and utilized for photocatalytic selective conversion of 4-methoxythiophenol (4-MTP) to bis(4-methoxyphenyl) disulfide (4-MPD) coupled with H2 evolution. In this dual-cocatalyst system, Co-Pi effectively captures and releases the holes from CdS through the chemical state change of Co to accelerate the surface thiols oxidation reaction, while GR is used as an electron collector and an active site for the proton reduction to H2. Consequently, the bifunctional GR-CdS-(Co-Pi) photocatalyst demonstrates significantly higher photoactivity than blank CdS. This work affords a new paradigm of incorporating dual-cocatalysts with semiconductor photocatalysts to efficiently take advantage of the photoinduced electrons and holes for photoredox-catalyzed cooperative coupling of organic transformation and H2 evolution.