Photocatalytic hydrogen evolution performance of NiS cocatalyst modified LaFeO3/g-C3N4 heterojunctions

Abstract

NiS cocatalyst modified LaFeO₃/g-C₃N₄ heterostructures were successfully prepared and their photocatalytic hydrogen evolution performance under visible light irradiation was presented. LaFeO₃/g-C₃N₄/NiS composites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma mass spectrometry (ICP-MS), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption desorption isotherms, UV-vis diffuse reflectance spectroscopy (DRS), transient photocurrent responses and electrochemical impedance spectroscopy (EIS). The results indicated that the LaFeO₃/g-C₃N₄/NiS heterostructures had enhanced photocatalytic hydrogen evolution performance than pure g-C₃N₄, LaFeO₃ and LaFeO₃/g-C₃N₄. 5%-LaFeO₃/g-C₃N₄/2%NiS exhibited the highest photocatalytic hydrogen evolution rate of 121 μmol g⁻¹ h⁻¹ under visible light, which was almost 60 times higher than the hydrogen evolution rate of 5%-LaFeO₃/g-C₃N₄. The effective separation of photogenerated electron–hole pairs in the LaFeO₃/g-C₃N₄ Z-scheme system with NiS as a cocatalyst enhanced the photocatalytic hydrogen evolution performance. This study provided a facile approach to prepare NiS modified LaFeO₃/g-C₃N₄ heterostructures and to construct an effective photocatalytic system for hydrogen evolution under visible light irradiation.