Black Trumpet Mushroom-like ZnS incorporated with Cu3P: Noble metal free photocatalyst for superior photocatalytic H2 production

Abstract

The development of the efficient photocatalysts with improved photoexcited charge separation and transfer is an essential for the effective photocatalytic H2 generation using light energy. So far, owing to the unique properties and characteristics, the transition metal phosphides (TMPs) have been proven to be high performance co-catalysts to replace some of the classic precious metal materials in the photocatalytic water splitting. In the present work, we report a novel copper phosphide (Cu3P) as a co-catalyst to form a well-designed fabricated photocatalyst with blacktrumpet mushroom-like ZnS semiconductor for the first time. The synthesis of Cu3P/ZnS consists of two-step hydrothermal and ball milling methods. The physical properties of the materials so prepared were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible diffuse reflectance spectroscopy (UV-DRS), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analyses. In order to study the role of Cu3P, electrochemical impedance spectroscopy (EIS) measurements were used to investigate the photogenerated charge properties of ZnS. The experiments of photocatalytic production of H2 confirm that the Cu3P co-catalysts effectively promote the separation of photogenerated charge carriers in ZnS, and consequently enhance the H2 evolution activity. The 3% Cu3P/ZnS sample delivers the highest catalyst activity and the consistent H2 evolution rate is14,937 µmol h−1 g−1cat, which is 10-fold boosted compared to the pristine ZnS. The stability of the catalyst was tested by reusing the used 3% Cu3P/ZnS photocatalyst in five consecutive runs, and their respective activity in the H2 production activity was evaluated. A possible mechanism is proposed and discussed.