Efficient Peroxymonosulfate Activation by Metallic Copper in TiO2–CaTiO3–Cu2O–Cu Anodes for Electrocatalytic Degradation of Organic Pollutants

Abstract

The development of heterogeneous electrodes with high conductivity and electrocatalytic activity is a crucial goal. Achieving this using a simple and low-cost method is essential for wastewater purification by anodic oxidation combined with peroxymonosulfate (PMS). Herein, TiO₂–CaTiO₃(CTO)-Cu₂O–Cu heterojunction electrodes are prepared by mixing CaCu₃Ti₄O₁₂ with different amounts of graphene oxide (GO). The different mixtures are pressed into pellets and sintered under inert atmosphere at 1100 °C for 3 h. The obtained pellets are used as anodes for PMS activation in the electrocatalysis. The efficiency of paracetamol (PCM) removal reaches its maximum (93%) after 90 min using the CTO–Cu–5GO electrode in a solution containing 10 ppm PCM, 210 mL sodium sulfate, and 0.5 mM PMS. The higher amount of metallic copper in this anode promotes the generation of radicals to effectively degrade PCM. In optimal conditions (1.2 V versus Ag/AgCl, 1 mM PMS, and 10 ppm PCM), PCM is completely removed in 45 min. According to the quenching test results, ^•O₂⁻ and ^•OH are the radicals generated during PCM degradation, and ^•O₂⁻ plays the main role. In this work, insights are provided into the rational combination of different metal oxides with TiO₂ as a heterostructure electrode to ensure high mineralization of pharmaceuticals by electrocatalysis.