Efficient Wastewater Remediation Enabled by Self-Assembled Perovskite Oxide Heterostructures with Multiple Reaction Pathways

Advanced oxidation processes (AOPs) are promising for the removal of retardant organic pollutants in water. However, traditional free-radicals-dominated AOPs are often limited by poor tolerance to water characteristics. Recently, creating nonradical processes has been considered as an effective strategy to overcome this limitation, while the function and mechanism of nonradical processes are still unclear in the important oxides catalytic systems. Herein, the nonradical-dominated peroxymonosulfate (PMS)-based AOPs are triggered on a heterostructural perovskite nanocomposite catalyst (La_0.4Sr_1.05MnO_4-δ), which is constructed from single and Ruddlesden-Popper perovskite phases by a facile self-assembled synthesis method. Noticeably, the phenol degradation rate of the heterostructural nanocomposite oxide is ∼2 times that of its individual components. This activity enhancement can be attributed to the abundant active oxygen vacancies, strong affinity to the reactants, and high-electron-transfer efficiency in the unique heterointerface of the nanocomposite. Furthermore, a ternary mechanism is unveiled: contaminants are oxidized not only by the function of radicals and singlet oxygen evoked from the active sites of perovskites but also by the transfer of their electrons to PMS via the beneficial surface of a heterostructral catalyst. This study provides new insights into nonradical-based AOPs derived from hybrid metal oxides in a PMS system.