Au-Pt alloy nanoparticles site-selectively deposited on CaIn2S4 nanosteps as efficient photocatalysts for hydrogen production

Au-Pt/CaIn2S4 composites were synthesized for the first time using the photoreduction method by which bimetallic Au-Pt alloy nanoparticles were in situ site-selectively photoreduced on the edges of monoclinic CaIn2S4 nanosteps. The Au-Pt alloy nanoparticles as cocatalysts can spatially separate the oxidation and reduction sites and effectively enhance the photocatalytic hydrogen activity of CaIn2S4 under visible light irradiation. When introducing 0.5 wt% Au-Pt alloy nanoparticles, the rate of hydrogen production could reach 107.6 mmol h(-1), which was higher than that of CaIn2S4, Au/CaIn2S4 and Pt/CaIn2S4 by a factor of 18.3, 2.37 and 2.4, respectively. The enhanced photocatalytic activity for hydrogen production could be attributed to the low recombination efficiency of the photogenerated charges and surface-plasmonresonance-induced effect of Au nanoparticles.