Efficient electrochemical dehalogenation of florfenicol without discharging toxic intermediates via direct electron transfer over electrochromic WO3

Abstract

Complete dehalogenation of florfenicol (FLO) was realized on a self-supporting, electrochromic WO3 nanocluster electrocatalyst prepared by anodization, effectively inhibiting the generation of toxic intermediates that can pose harmful influence on the ecosystem. Three dimensional, omnidirectional WO3 clusters made up of WO3 nanoflakes are grown from a W mesh substrate, which can work as catalyst and electrode enable the complete dehalogenation via a direct electron transfer because of the inherent electron-storage and self-supporting nature. Assisted by bias potential, continuous electron streams are generated and reserved in the porous WO3 interface, building an electron-rich circumstance for activating the C–Cl and C–F bonds to detach the halogen groups. The best electrocatalytic dehalogenation performance, 99.7% in 120 min was acquired using the optimal WO3/W anodized at 25 V. The possible sites attacked by electrons is predicted by Fukui index, that is evidenced by the MS of intermediates originated from FLO decomposition. ECOSAR simulation and E. coli surviving evaluation verifies that there is no hazard on ecosystem of the chemicals without –F and –Cl. Particularly, the self-supporting WO3 nanocluster electrocatalyst exhibits a superior durability with no decay in activity after 20 h running, indicating a promising prospect in establishing a feasible, cost-effective, and durable electrochemical strategy for antibiotic dehalogenation.