Preparation of Ti/SnO2-Sb2O4-La/β-PbO2 electrode and its electrochemical oxidation performance of dye wastewater

In this work, Ti/SnO2-Sb2O4-La/beta-PbO2 electrode was successfully prepared by electrodeposition method. The surface morphology, crystal structure, elemental states and electrochemical characteristics of the electrode were examined by SEM, XRD, XPS, CV, and LSV. The results demonstrated that the conductivity, specific surface area, electrochemical oxidation performance and stability of the beta-PbO2 coated electrode with SnO2-Sb2O4-La as the intermediate layer were greatly improved. Under the conditions of initial rhodamine B (RhB) concentration of 20 mg/L, initial pH of 3.0, electrolyte concentration of 0.1 M, and current density of 30 mA cm(-2), the removal rates of color and TOC reached 100 % and 83.64 % after 20 mins and 30 mins, respectively. The electrode can also completely degrade methylene blue and methyl orange wastewater after 30 mins under the same conditions. The accelerated lifetime of the electrode reached 175 mins (1000 mA cm(-2), 1 M H2SO4), and the actual lifetime was up to 3208 hrs. Based on the results of free radical quenching experiment and GC-MS detection, RhB degradation pathway was proposed: the aniline-based conjugated system of RhB molecule was attacked by the combined action of free radicals (indirect oxidation) and electrocatalysis (direct oxidation), which decomposed macromolecules into small molecules and ultimately mineralized them into CO2 and H2O. This work is expected to provide a fresh research concept for preparing DSA electrodes with excellent catalytic performance and high stability.