Solar-accelerated chemoselective hydrogenation of 4-nitrostyrene to 4-vinylaniline with carbon dot-induced Cu over Cu3P in the absence of any sacrificial reagent

We present an efficient method toward rational design and fabrication of multicomponent photocatalysts using carbon dots (CDs) for solar-driven chemical reactions with super selectivity and activity. CDs act not only as a reductant to enable metallic Cu formation but also as a hole trapping agent to hinder side reactions. By simple pyrolysis of the mixture of the Cu source, CDs and NaH2PO2, the Cu3P–CDs–Cu nanocomposite is produced and shows a good sunlight harvesting property. Under one sun irradiation, Cu3P–CDs–Cu can catalyze ammonia borane (AB) for selective hydrogenation of 4-nitrostyrene (4-NS) to 4-aminostyrene (4-AS) in an aqueous solvent at room temperature, achieving 100% selectivity and beyond 99% conversion rate within a few short minutes of reaction time. The superior performance of Cu3P–CDs–Cu is attributed to the formation of the all-solid-state Z-scheme photocatalytic system, eliminating the high-energy holes—active species attacking CC groups in 4-NS—from Cu3P. Meanwhile, metallic Cu promotes the migration and transport of excited electrons from the interior to the surface and interface, accelerating the activation of AB for selective reduction of 4-NS to 4-AS.