Visible-Light-Responsive Pt–Cu(OH)2/ZnIn2S4 Catalysts for Efficient Nonsacrificial H2 Production from Water

Photoplatinized Cu(OH)2/ZnIn2S4 catalysts synthesized using a hydrothermal process and simple deposition methods are showing promising efficiencies in photosynthetic water-splitting reactions without any sacrificial agents present. The prepared Cu(OH)2/ZnIn2S4 with different weight percentages of Cu(OH)2 and Pt were characterized by XRD, SEM, XPS, and EDX analyses. The results revealed that both Pt and Cu(OH)2 are intimately coupled with ZnIn2S4 (ZIS). While the pristine ZIS produced only 75.95 μmol of H2 per gram of material in 6 h of irradiation, the yield significantly enhanced to 292.90, 1153.64, and 1175.05 μmol per gram with 1%-Cu(OH)2/ZIS, 1%-Pt-1%-Cu(OH)2/ZIS, and 2%Pt-1%-Cu(OH)2/ZIS, respectively. The 1%-Cu(OH)2/ZIS with 1–2% Pt loading showed ∼15, ∼4, and ∼2 times higher H2 evolution efficiency than pure ZIS, 1%-Cu(OH)2/ZIS, and 1%-Pt/ZIS (575.1 μmol of H2 per gram of material), respectively. This significant enhancement in activity is attributed to the enhanced lifetime of photogenerated charge carriers, based on photoluminescence data. No H2 production is observed using CdS, Cu(OH)2 and CuO over 6 h of irradiation under identical conditions. It is concluded that Pt–Cu(OH)2/ZIS is an efficient visible-light-responsive material and it could offer a new direction for the development of an efficient visible-light-responsive semiconductor for nonsacrificial photosynthetic solar water splitting.