Oxygen vacancy mediated Ruddlesden-Popper Cu-based perovskites wih a dual-reaction-center for enhanced fenton-like removal of coal pyrolysis wastewater

[Display omitted] •Oxygen vacancy mediated L2-xCO catalysts were designed via cation-deficiency.•A dual-reaction-center structure was formed by oxygen vacancy and ≡Cu(II)•Methyl group in phenolic increased electron transfer between dual-reaction-center.•DFT results showed that the OV enhanced H2O2 adsorption and O-O stretching.•Catalytic mechanism and DMP decomposition path were investigated. The treatment of coal pyrolysis biochemical effluent has always been a serious problem in coal chemical process. However, improving the removal capacity of wastewater based on the characteristic of coal pyrolysis wastewater (CPW) has not been well investigated. In this work, the cation deficiency of Cu-based perovskite was used to couple with ≡Cu(II) to form dual-reaction-centers catalyst, which would improve the degradation of CPW in the heterogeneous Fenton-like system. According to the characterization, the La-deficiency could induce the generation of surface oxygen vacancy (OV) on the surface of L2CO perovskites, which would regarded as electron-rich center. Afterwards, ≡Cu(II) and dimethylphenol (DMP) were treated as electron-poor center and electron donor to accelerate electron transfer. The experimental results indicated that the L1.8CO sample achieved higher degradation activity than that of bulk L2CO sample for DMP degradation. The hydroxyl radical (∙OH) was the main function for the catalytic degradation of DMP. Significantly, the methyl group in phenolic pollutants could benefit to transfer electron in the electron-rich/poor reaction centers. Moreover, the density functional theory (DFT) calculation revealed that the introduction of surface OV would promote H2O2 adsorption and strengthen electron transfer between H2O2 and L1.8CO sample. Meanwhile, the DMP degradation pathways were also deduced by DFT calculation and UPLC-QTOF/MS analysis. The L1.8CO sample showed excellent recycling performance and catalytic stability during the heterogeneous Fenton-like process. This study developed a new perspective for designing more effective heterogeneous Fenton-like materials for CPW removal.