Optimizing oxygen vacancy concentration and electronic transport processes in a MnxCo/CeO2 nanoreactor: regulation mechanism of the radical to non-radical pathway

Abstract

Enhancing the efficiency of electron transfer and augmenting the utilization rate of peroxymonosulfate (PMS) pose challenges for advanced oxidation processes (AOPs). A high-performance bimetallic-doped catalyst (MnCo/CeO₂) with an appropriate concentration of oxygen vacancies (OVs) was successfully designed using a straightforward synthesis strategy. It primarily activates PMS through non-radical pathways. Systemic characterization, experiments, and theoretical calculations have demonstrated that reasonable OVs and the Mn/Co bimetallic doping strategy effectively modulated the surface spatial electron structure and greatly improved interfacial electron transfer processes (ETP). Ultimately, MnCo/CeO₂ exhibits a remarkable ciprofloxacin (CIP) removal efficiency of 93.71% (k = 0.03501 min⁻¹) within 50 min (after 5 cycles, 89%), which is 5.03 times faster than that of traditional CeO₂ (k = 0.00696 min⁻¹), and the possible degradation pathway as well as toxicity of intermediate products were identified using LC-MS, Fukui function analysis, and toxicity evaluation. This work proposes a feasible strategy for designing bimetallic-doped metallic oxide catalysts, which have great application potential for the degradation of organic contaminants under actual harsh environmental conditions.