Activating copper by creating low-coordinated copper sites for antibiotic detoxification through Electrocatalytic hydrodechlorination reaction

Electrocatalytic hydrodehalogenation (ECHD) offers a sustainable venue for detoxifying halogenated antibiotics by converting CX (XBr, Cl and F) bonds to CH bonds. Metallic copper (Cu) is a promising catalyst with higher chemical stability compared to general cobalt-based catalysts but suffers from lower activity toward dilute antibiotic pollutants. Herein, we activated the Cu by creating numbers of low-coordinated Cu sites on skeleton surface of a Cu foam electrode (r-CF) through a stepwise calcination and electrochemical reduction (C-ER) process. The r-CF electrode demonstrated extraordinary activity in FLO removal with a mass activity of 3.3 g_FLO h⁻¹ m⁻². More importantly, it achieved 100 % conversion of CCl bonds at a relatively mild potential of −0.30 V, outperforming pristine Cu foam electrode (64.6 %) and most reported catalysts. Mechanistic studies revealed that the low-coordinated Cu sites exhibited an upshift d band center towards Fermi level, which facilitated pollutant adsorption and electron transfer on these sites. Furthermore, the C-ER processing increased the roughness of the skeleton, enlarging the laminar region in the vicinity of active sites and enhancing the turbulent state around the electrode during ECHD. These dual enhancement contributed to the mass transfer of FLO from bulk solution to electrode and their stabilization at active sites. The r-CF was further applied to detoxify a FLO-contaminated lake water sample. It was able to reduce the antibacterial activity of the water by 81.7 %. This work offered a new approach to activate the Cu for ECHD, and demonstrated the promise of Cu-mediated ECHD for antibiotics contamination remediation.