Efficient photocatalytic degradation of phenolic pollutants using MIL-100(Fe)@Zn3In2S6 Z-scheme heterojunction

Abstract

In this work, we used a simple hydrothermal method to in-situ grow Zn₃In₂S₆ on MIL-100(Fe) octahedra, and obtained a MIL-100(Fe)@Zn₃In₂S₆ Z-scheme heterojunction photocatalyst. We systematically studied its performance in degrading phenol and p-nitrophenol (PNP) under visible light. MIL-ZIS₆-2 can remove 89.1 % of phenol within 120 min and nearly 100 % of PNP within 60 min. Its photocatalytic activity to the degradation of phenol is 30.7 times and 1.7 times higher than that of MIL-100(Fe) and Zn₃In₂S₆, respectively. And the photocatalytic activity to degrade PNP is 18.2 times and 1.4 times higher than MIL-100(Fe) and Zn₃In₂S₆. Further research was conducted on its band structure and photocatalytic response mechanism through photoelectric performance, ultraviolet photo-electron spectroscopy, and electron spin resonance spectrometer testing. The results showed that the formation of Z-scheme heterojunction not only increased the specific surface area of the composite photocatalyst, enabling it to provide more reaction sites, but also effectively suppressed the recombination of photogenerated holes and electrons, improving the redox ability of the photocatalyst. This work provides a new perspective for constructing efficient Zn₃In₂S₆-based composite photocatalysts and addressing environmental issues.