Construction of acidic microenvironments to overcome the pH dependence of iron-based catalysts and application to the degradation of micropollutants by AOPs.

• Propose a design route for novel iron-based catalysts to overcome the macroscopic pH limitation of AOPs. • Construction of acidic microenvironments at catalyst heterogeneous interfaces guided the activation of PMS and degradation of pollutants. • The mechanism of the macro-chemical environment influences reactive oxygen components in the process of AOPs. Iron-based catalysts are considered one of the most promising catalysts for AOPs. However, the dependence on an acidic working environment is a bottleneck for its development and widespread application. Meanwhile, the strong acidity of persulfate makes the mechanism of pH influence on the process of AOPs ambiguous. In this study, we report a co-catalyzed non-homogeneous phase-like Fenton-like system to achieve sustained degradation of organic pollutants such as sulfamethoxazole in neutral or alkaline buffer solutions. It exploits the proton trapping property of active sulfur in MoS 2 to construct an acidic microenvironment at the heterogeneous interface of the catalyst, which ensures the stable cycling of iron ions on the catalyst's surface and effectively inhibits the generation of iron sludge. Meanwhile, the influence of the chemical environment on ROS during PMS activation was explored using a buffer solution system, which provided new insights into the transformation mechanism of ROS during AOPs. [ABSTRACT FROM AUTHOR]