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In this study, the physicochemical and photocatalytic properties of two kinds of stannate perovskite oxides (MgSnO 3 and CaSnO 3) were investigated under simulated sunlight, where dimethyl phthalate (DMP) and diethyl phthalate (DEP) were selected as the probe pollutants. The results of photochemical characterization showed that MgSnO 3 perovskite exhibited better photocatalytic performance than CaSnO 3 perovskite. MgSnO 3 perovskite could effectively degrade 75% of DMP and 79% of DEP through pseudo-first-order reaction kinetics, which remained good in pH 3.0 to 9.0. Quenching experiments and electron paramagnetic resonance (EPR) characterization indicated that photogenerated holes (h +), superoxide (O 2 −), and hydroxyl radicals (OH) worked in the photo-degradation, while O 2 − played the most important role. Furthermore, intermediates identification and density functional theory (DFT) calculations were used to explore the degradation mechanism. For both DMP and DEP, the reactive oxygen species (ROS, including O 2 − and OH) were responsible for the hydroxylation of benzene ring and the breaking of the aliphatic chain, while h + was prone to break the aliphatic chain. This work is expected to provide new insights on the photocatalytic mechanism of stannate perovskites for environmental remediation. [Display omitted] • MgSnO 3 and CaSnO 3 perovskites were firstly used for photocatalytic degradation of PAEs. • MgSnO 3 perovskite exhibited better photocatalytic performance. • h + and O 2 − were the predominant radicals in photo-degradation. • Experiments and DFT calculations were combined to elucidate the degradation mechanism. [ABSTRACT FROM AUTHOR]

• A photo-switch to control PDS non-radical/radical activation over CFO is developed. • Non-radical activation has high PDS utilization and less halogenated byproduct generation. • Radical activation has fast degradation rate and strong mineralization ability for pollutants. • QSARs of phenolic pollutants were found to provide instructions of pathway choice. This work presents a novel strategy for peroxydisulfate (PDS) activation under controlled non-radical/radical mechanism, which is based on a photo-switch over layered CuFe oxide (CFO). The non-radical mechanism is attained by CFO under dark environment, and the radical mechanism is achieved through the visible light irradiation. Electron paramagnetic resonance (EPR) and density functional theory (DFT) studies demonstrate the non-radical activation mechanism is conducted by the polarization effect of CFO to PDS molecule. The radical mechanism could be elucidated by the one-electron reduction of the PDS by excited electrons on conduction band of CFO. Products analyses based on HPLC-MS and Fukui functions suggest that the non-radical degradation pathway could decrease the generation of halide intermediates, whereas the radical pathway may not be observed with this property. Quantitative structure-activity relationships (QSARs) were established between the observed pseudo-first-order rates of various phenolic pollutants and the classical descriptors (i.e., Hammett constant, Pka, E HOMO and E LUMO) in the non-radical and radical systems, respectively, to give instructions of pathway choice for different pollutants. Considering the non-radical/radical pathway both have their own unique strengths (e.g., non-radical pathway has high selectivity to pollutants and high utilization efficiency of oxidant, and radical pathway has considerable degradation rate and strong mineralization ability), these pathways should be chosen wisely for pollutant degradation according to reality conditions. [ABSTRACT FROM AUTHOR]