The effects of amount of la on the photocatalytic performance of ZnIn₂S₄for hydrogen generation under visible light

A series of La modified ZnIn₂S₄ photocatalysts (x wt% La-ZnIn₂S₄, x = 0, 0.02, 0.1, 0.5, 1.0, 2.0, 5.0, 10.0) were prepared using the hydrothermal method and characterized by various analysis techniques, such as UV-Vis, XRD, SEM, EDX, TEM, BET and PL. The results indicated that the La element existed as the oxide La₂O₃ which was located on the surface of ZnIn₂S₄ petals. The increase in La amount can reduce ZnIn₂S₄ crystallite size, inhibit ZnIn₂S₄ grain growth, promote ZnIn₂S₄ crystallite self-organization into a micro-sphere with flower-like morphology, increase ZnIn₂S₄ surface area and total pore volume, and bring rich defects to ZnIn₂S₄, indicating that the properties of these photocatalysts greatly depended on the amount of La added. The photocatalytic activities of La-ZnIn₂S₄ were evaluated based on photocatalytic hydrogen production from water under visible-light irradiation and the hydrogen production efficiency increased by 60.6%, 110.8%, 129.8%, 141.6%, 103.7%, 79.3% and 83.2% after adding 0.02 wt%, 0.1 wt%, 0.5 wt%, 1.0 wt%, 2.0 wt%, 5.0 wt% and 10.0 wt% of La, respectively. On the basis of the characterization of the catalysts, the effect of the amount of La added as a modifier on the photocatalytic activity of La-ZnIn₂S₄ was studied.