Construction of efficient and durable noble-metal-free CuCo₂S₄ nanoarray anodes for chlorine evolution and antibiotic degradation

The chlor-alkali industry faces high energy consumption, competition between the chlorine evolution reaction (CER) and oxygen evolution reaction (OER), and challenges, such as high costs and poor stability of precious metal catalysts in chlorine production. At the same time, the treatment of antibiotic pollution urgently requires efficient degradation technologies. In this study, a non-precious metal anode of CuCo₂S₄/Ti (CCS/Ti) with a nanosheet structure was constructed on a foam titanium substrate using a hydrothermal method, achieving dual-functional applications for efficient chlorine evolution and the degradation of ofloxacin (OFX). The electrode exhibits an overpotential of 1.23 V (vs. Ag/AgCl) at a current density of 100 mA·cm⁻², with a Faradaic efficiency of 95.66%, and remains stable for 180 h. Density functional theory (DFT) calculations indicate that the chlorine evolution mechanism on the CCS/Ti electrode primarily follows the Volmer–Heyrovsky pathway. Furthermore, the CCS/Ti electrode achieves a degradation efficiency of 91.34% for OFX within 5 min and demonstrates broad-spectrum degradation capabilities for various fluoroquinolone antibiotics (> 83.05%). This study provides an efficient and cost-effective new approach for catalyst material design, contributing to the greening of the chlor-alkali industry and the treatment of refractory pollutants.