Solar-Driven Imidazoles and Hydrogen Coproduction from Benzylamine over Au Nanoparticle-Decorated Zn2In2S5

Solar-driven photocatalytic hydrogen production integrated with high-value organic transformation has emerged as a promising and advanced paradigm for solar energy utilization. Herein, we successfully realize the coupled production of high-value imidazole derivatives and hydrogen via the photocatalytic conversion of benzylamine (BA) over Au nanoparticle-decorated Zn2In2S5 (Au-ZIS) under sunlight irradiation. The Au nanoparticles (Au NPs) significantly boost the accessibility of photocarriers for interfacial redox reactions through the localized surface plasmon resonance (LSPR) effect. Under the optimal Au loading, the Au-ZIS achieves apparent quantum yields (AQY) of 3.41% at 380 ± 20 nm and 0.82% at 420 ± 20 nm for the transformation of BA to 2,4,5-triphenyl-1H-imidazole (TI). Mechanistic investigations reveal that the selectivity toward imidazole products is attributed to the presence of Au NPs, which accelerates the conversion of N-benzylbenzaldimine (NBBI), a critical intermediate responsible for heterocycle construction. This work not only provides a feasible guideline for the rational design of high-efficiency photocatalysts toward the valorization of organic substrates but also offers mechanistic insights into the photocatalytic transformation of BA.