The effects of amount of La on the photocatalytic performance of ZnIn2S4 for hydrogen generation under visible light

Abstract

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.