The Persistent Generation of H2O2 During the Phenol Photocatalytic Degradation Over Flower-Like ZnIn2S4

Phenol photocatalytic degradation typically relies on the consumption of oxidative species such as H2O2. In this study, we found the persistent H2O2 generation promoted by the phenol photocatalytic degradation process over flower-like ZnIn2S4 under visible light. The H2O2 generation efficiency achieved 626 mu mol<middle dot>g(-1)<middle dot>h(-1), which was 5.35 times higher than in pure water, whereas the phenol degradation efficiency was 97.34%. Experimental and theoretical analysis showed that H2O2 was generated via a two-electron O-2 reduction reaction over ZnIn2S4. Meanwhile, phenol was attacked by the photogenerated holes which facilitated H2O2 production. More interestingly, phenol degradation process can also promote the H2O2 generation, in which hydroquinone (HQ), as the key intermediate, played an important role in promoting the persistent generation of H2O2. This work provided new insights into the in-situ production of H2O2 accompanied with the purification of contaminated water.