Coordinating ultra-low content Au modified CdS with coupling selective oxidation and reduction system for improved photoexcited charge utilization

Abstract Integrating ultra-low content precious metal and low-cost solid-state optical absorber for effective utilization of photogenerated charges has been a hopeful strategy for selective organic transformations (SOTs). Herein, series of novel Au/CdS nanocomposites with (ultra-) low-content Au were prepared via two-step solvothermal treatment for the selective oxidation (SO) of aromatic alcohols (AA) and selective reduction (SR) of nitroarenes (NA) in one coupling system. Taking the advantages of electron accumulator property of Au and virtues of formed tight heterojunction between 5 nm gold nanoparticle (Au NPs) and CdS nanorods (CdS NRs), the Au/CdS nanocomposites exhibited outstanding charge separation and transfer performance and durable stability compared with blank CdS. The activities corresponding to the oxidation of aromatic alcohols and reduction of nitroaromatic hydrocarbons on the optimal 0.0028% Au/CdS samples are about 2 and 4 times higher than those of blank CdS. This is mainly due to the introduction of Au NPs and the construction of reasonable coupling reaction system, thus realizing the synergistic utilization of photogenerated charges. Finally, the mechanism and photocatalytic reaction pathway for the coupling reaction system were also proposed.