CuS/ZnS hexagonal plates with enhanced hydrogen evolution activity under visible light irradiation

• Preparation of CuS/ZnS hexagonal plates by solvothermal reaction and subsequent cation-exchange reaction.
• Visible light photocatalytic activity for H2 evolution without cocatalyst.
• The H2-evolution rate depends on the CuS content.
• The highest H2-evolution rate is 77 times of that of the CuS-ZnS mechanical mixture.

CuS/ZnS hexagonal plates were prepared through a solvothermal and subsequent cation-exchange reaction between the as-prepared precursor and Cu(NO3)2 aqueous solution. The as-prepared CuS/ZnS composite photocatalysts were characterized by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), UV–Vis diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. The CuS/ZnS hexagonal plates exhibited efficient photocatalytic H2 evolution activity from an aqueous Na2S and Na2SO3 solution without noble metal loading. The composite photocatalyst with 6% CuS content displayed the highest photocatalytic activity (1233.5 μmol h− 1 g− 1), which was almost 77 times higher than that of the mechanical mixture of CuS and ZnS. The enhanced visible light-induced photocatalytic activity is likely a result of the interfacial charge transfer of the CuS/ZnS heterojunction. Our proposed photocatalytic mechanism is supported by XPS and PL results.

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