FeCo-ZIF derived carbon-encapsulated metal alloy as efficient cathode material for heterogeneous electro-Fenton reaction in 3-electron ORR pathway: Enhanced performance in alkaline condition

Abstract

Oxygen reduction reaction via 3-electron pathway presents a promising approach for generating reactive oxygen species in heterogeneous electro-Fenton (H-EF) process. This approach overcomes the limitations posed by the slow accumulation of H2O2 via 2- electron ORR and the inefficient activation of H2O2 through Haber-Weiss cycle. In this study, bimetal alloy nanoparticles were encapsulated within carbon layers (FeCo/C) by a general MOF-derived strategy, resulting in an overall electron transfer number of 2.98 during the H-EF process. Under optimal modification conditions, the prepared FeCo/C exhibited exceptional performance in sulfamethoxazole removal. Furthermore, the performance was enhanced under alkaline conditions. The apparent rate constant increased from 0.02 to 0.03 min−1 as the pH value increased from 3 to 11. The mechanism underlying this alkalinity-enhanced activity was attributed to the involvement of a surface-independent outer sphere electron transfer component, which provides valuable insights into the potential application of the H-EF process for treating alkaline wastewater.