Construction of novel spherical ZnIn2S4–Ag–LaFeO3 heterostructures for enhancing photocatalytic efficiency

Herein we report novel photocatalysts ZnIn₂S₄–Ag–LaFeO₃ with the core–shell structured materials prepared by hydrothermal method. In order to improve the efficiency of photocatalytic degradation of pollutants, LaFeO₃ was prepared by hydrothermal followed by calcination, and further Ag nanoparticle (NP) was loaded onto the spherical structure of LaFeO₃ by photolysis of silver nitrate, and finally the spherical ZnIn₂S₄–Ag–LaFeO₃ photocatalyst was prepared by hydrothermal method again. The structure and properties of the as-prepared materials were characterized by X-ray photoelectron spectroscopy, ultraviolet–visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy and fluorescence spectra. The results show that the synthesized composite photocatalysts display a significant improvement in photocatalytic efficiency relative to the single LaFeO₃ and ZnIn₂S₄ and form a core–shell structure. Furthermore, the effect of the ratio of each component on the photocatalytic efficiency was investigated in detail, and it is discovered that at an Methylene Blue (MB) concentration of 0.219 mol/L, the degradation rate of MB is 95% at 120 min using 0.02 g of catalyst with an ideal ZnIn₂S₄:Ag:LaFeO₃ ratio of 10:0.5:1. The possible mechanisms to improve the photocatalytic efficiency were explored.