Enhanced electron transfer and hydrogen peroxide activation capacity with N, P-codoped carbon encapsulated CeO₂ in...

Designing catalysts that can effectively activate oxygen and hydrogen peroxide is a huge challenge in electro-Fenton (EF) process. Considering the superior ability of electrons transport and activation of H₂O₂, ceria encapsulated with N, P-codoped carbon material was a promising catalyst for EF reaction. Herein, CeO₂-NPC_T^X (where T and X represented the calcination temperature and the initial mass of CeO₂, respectively) materials were synthesized via pyrolysis process and used as catalysts to degrade ciprofloxacin (CIP) in EF process. The results indicated that CeO₂-NPC₁₀₀₀¹⁰⁰ catalyst had good degradation performance under the optimal conditions. Compared with CeO₂ and CeO₂-NC₁₀₀₀¹⁰⁰ catalysts, CeO₂-NPC₁₀₀₀¹⁰⁰ catalyst had more content of graphite N and more oxygen vacancies, which were beneficial to activation of oxygen and hydrogen peroxide. Scavenging experiments and electron paramagnetic resonance analysis confirmed ·O₂^- and ·OH were the main reactive oxygen species in the CIP degradation process. And three logical degradation routes of CIP were given. In addition, CeO₂-NPC₁₀₀₀¹⁰⁰ catalyst still had good stability after three times of continuous operation, and presented good universality for the treatment of a variety of antibiotic wastewaters. Finally, a convincing mechanism in the EF system with CeO₂-NPC₁₀₀₀¹⁰⁰ for CIP degradation was proposed.