Dual interfacial synergism in Au-Pd/ZnIn2S4 for promoting photocatalytic selective oxidation of aromatic alcohol

Abstract

Visible-light-responsive semiconductor decorated with bi-metal nanoparticles synergistic photocatalysts are promising in photocatalysis. Herein, bi-metal nanoparticles Au-Pd decorated ZnIn2S4 nanosheets photocatalytic system was constructed and applied in reaction of photocatalytic selective oxidation of of aromatic alcohols. Various parameters including loading ratio of two metal, loading amount, solvents, time, reactant were investigated. The optimal 0.5 wt% Au-Pd/ZnIn2S4 photocatalysts was founded to exhibit the highest photocatalytic activity, which is 1.5, 2.0 and 1.3 times higher than pristine ZnIn2S4, Au/ZnIn2S4 and Pd/ZnIn2S4, respectively. Characterization results confirmed enhanced visible-light harvesting capability as well as superior photoinduced carriers’s separation and transfer behavior, enhanced O2 adsorption and reduction ability of Pd and surface reaction kinetics account for enhanced photocatalytic activity, in addition, which ascribed to dual metal synergistic effect and metal-semiconductor interaction in Au-Pd/ZnIn2S4 system. Finally, the corresponding reactive radical species was confirmed by ESR and other method. Based on the experimental data and analysis, possible reaction mechanism is proposed. The photogenerated h+, O2− and carbon centered radicals are responsible for the reaction. This systemic work shed light on the bi-metal decorated semiconductor photocatalyst, where metal-metal interaction as well as metal-semiconductor cooperated together to improve the performance of catalysts in visible-light-driven organic transformations.