Photocatalytic Hydrogen Evolution Performance and Photogenerated Charge Transfer Properties of p-Type Copper Sulfide.

Two kinds of 3D hierarchically nanostructured CuS samples were synthesized via hydrothermal method and studied as photocatalysts for H₂ evolution. Field-emission scanning electron microscopy (EF‑SEM) and X-ray diffraction (XRD) were used to characterize the samples. The rate of H₂ evolution over CS1 sample is 459.8 μmol g^–1 h^–1, which is 9.4 times higher than that over CS2. CuS shows excellent photocatalytic H₂ evolution activity only with Na₂S and Na₂SO₃ as holes sacrificial agent. The transient photovoltage (TPV) measurement was used to study the surface photoelectric properties of the samples. Based on the photovoltage response, the influence of the transfer characteristics of photogenerated charge carriers on photocatalytic activity is discussed. The results indicate that the charge separation efficiency of CS1 is higher than that of CS2. The photogenerated charge carriers life time of CS1 is longer than that of CS2; this is the main reason of the higher photocatalytic activity of CS1. [ABSTRACT FROM AUTHOR]