Construction of a Pr/CDs/SSS/PbO2 composite electrode for highly efficient degradation of organic pollutants†

In this study, a Pr/CDs/SSS/PbO₂ electrode with good electrocatalytic activity and superior stability was successfully prepared by an electrodeposition process. XRD results showed that the doping of the Pr element inhibited the PbO₂ crystal growth, resulting in the complete disappearance of the α-PbO₂ diffraction peaks. Compared with the pure PbO₂ electrode, the Pr/CDs/SSS/PbO₂ electrode possesses a smaller grain size and a more compact electrode surface structure. In addition, the results of XRD and XPS confirmed that Pr³⁺ and Pr⁴⁺ existed simultaneously in the electrode, which increased the oxygen precipitation over potential (1.96 V) and reduced the interfacial resistance (5.01 Ω) of the Pr/CDs/SSS/PbO₂ electrode. Significantly, the prepared Pr/CDs/SSS/PbO₂ electrode showed the highest catalytic activity when the electrode was prepared in 5 mmol L⁻¹ of Pr-containing solution, and the degradation of MB by the Pr/CDs/SSS/PbO₂ electrode was 98.2% after 180 min of degradation under the conditions: 50 mg L⁻¹ of MB, pH = 5, and 30 mA cm⁻² of current density. The removal rate of TOC was 58%, which was much higher than that of the pure PbO₂ electrode (3.44%). In general, the Pr/CDs/SSS/PbO₂ electrode can be considered an efficient and low-cost anode material for the electrochemical treatment of organic wastewater.