Ce-doped three-dimensional graphite felt/PbO2 anode: single-step room-temperature electrodeposition and efficient electrocatalytic degradation of tetracycline

Abstract

A three-dimensional GF/PbO₂-Ce electrode was developed by depositing Ce-doped β-PbO₂ crystals onto a graphite felt (GF) substrate via single-step electrodeposition under room-temperature conditions. The characterization results revealed that the GF/PbO₂-Ce electrode exhibited an enhanced specific surface area and superior electrocatalytic performance compared to the GF/PbO₂ and the bare GF electrodes. The influencing factors and reaction mechanisms based on the GF/PbO₂-Ce electrode for tetracycline (TC) degradation were investigated through electrochemical oxidation experiments. Optimal conditions were established with a pH of 3, a Na₂SO₄ concentration of 0.04 mol L⁻¹, and a current density of 7 mA cm⁻². Under the optimized conditions, 95.25% of 30 mg L⁻¹ TC was degraded in 30 min and 85.65% chemical oxygen demand (COD) removal was achieved in 120 min. The contributions of direct and indirect oxidation in the TC degradation process were determined through radical quenching experiments. Based on the results of liquid chromatography-mass spectrometry (LC-MS), degradation pathways for TC were proposed. After 5 cycles of reuse, the electrode remained at a degradation efficiency above 93%, demonstrating the stability of the GF/PbO₂-Ce electrode and its potential as a promising electrode for the degradation of TC.