A 2.5D electrode system constructed of magnetic Sb-SnO₂ particles and a PbO₂ electrode and its electrocatalysis application on acid red G degradation

A novel electrode consisting of a Ti/PbO₂ shell and Fe₃O₄/Sb-SnO₂ particles was developed for electrochemical oxidation treatment of wastewater. Scanning electron microscope (SEM), X-ray diffraction (XRD), the current limiting method, toxicity experiments, and high-performance liquid chromatography were adopted to characterize its morphology, crystal structure, electrochemical properties, the toxicity of the wastewater, and hydroxyl radicals. Acid Red G (ARG), a typical azo dye, was additionally used to test the oxidation ability of the electrode. Results indicated that the 2.5D electrode could significantly improve the mass transfer coefficient and •OH content of the 2D electrode, thereby enhancing the decolorization, degradation, and mineralization effect of ARG, and reducing the toxicity of the wastewater. The experiments revealed that, at higher current density, lower dye concentration and higher temperature, the electrochemical oxidation of ARG favored. Under the condition of 50 mA/cm², 25 °C, and 100 ppm, the ARG, Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiency reached 100%, 65.89%, and 52.52%, respectively, and the energy consumption and the current efficiency were 1.06 kWh/g COD, 8.29%, and energy consumption for TOC and mineralization current efficiency were 3.81 kWh/g COD, 9.01%. Besides, the Fe₃O₄/Sb-SnO₂ particles after electrolysis for 50 h still had remarkable stability. These results indicated that the ARG solution could be adequately removed on the 2.5D electrode, providing an effective method for wastewater treatment.