Cu quantum dots anchored core-shell submicrosphere catalyst for electro-enhanced degradation of diclofenac sodium

The low mass transfer efficiency, sluggish redox cycles of metal ions, and poor recycling rate of S2O82-→SO42-→S2O82- greatly limit the application of two-dimensional (2D) electrodes and persulfate (PS) techniques. In this study, an interface engineering strategy was developed to anchor Cu quantum dots (CuQDs) onto a novel Cu-CoO@NC (N-doped carbon) core-shell submicrosphere catalyst. The 3D electrochemical system (2D electrodes combined with Cu-CoO@NC particle electrodes) exhibited excellent catalytic behavior with 99.1% removal of diclofenac sodium in 30 min. The Cu-CoO@NC catalyst presented effectiveness and strong environmental adaptability in a broad pH range, in actual water bodies, and for multiple PPCPs. Based on the results analyses of experiments and density functional theory (DFT) calculations, the excellent performance of Cu-CoO@NC/PS during electrochemical oxidation (EO) are results from the effective mass transfer, efficient interfacial charge transport, rapid redox cycling of bimetallic ions promoted by cathode, repetitive cycle of S2O82- → SO42- → S2O82- caused by anode and multiple active sites of PS.