Vanadium doped Fe-Mn bimetallic oxides as cathodic materials for boosted heterogeneous electro-Fenton degradation of organic contaminants

Abstract

The design of cathode materials with both sustainable H2O2 selectivity and accelerated recyclable regeneration remains a challenge for contaminants removal in heterogeneous electro-Fenton (HEF) process. Herein, a series of ternary Fe0.50Mn0.5−δVδOx (δ = 0.005, 0.01, 0.05) metal oxides have been synthesized and employed as cathodic materials for the degradation of various organic contaminants in water matrix. 99.7 % removal rate was achieved for carbamazepine (CBZ) in 60 min with 98.8 % mineralization rate. Simultaneously, the catalyst exhibited outstanding degradation efficiency (96.0–99.7 %) with other pollutants including sulfonamides (SMX), bisphenol A (BPA), 2,4-dichlorophenol (2,4-DPC) and ofloxacin (OFX), demonstrating its potential application. Factors affecting the EF process, including current density, pH, oxygen flow rate and compatibility of inorganic anions were thoroughly evaluated and the degradation mechanism was studied in detail. Density functional theory (DFT) calculations revealed that the improved catalytic efficiency was originated from vanadium doping to access optimized electronic structure, which endows enhanced 2e− ORR selectivity as well as excellent overall performance for the EF process. This work may enrich the study on EF system and offers a promising strategy for contaminants removal with FeMnVO materials in water treatment applications.