Copper foam-supported CuxO nanorod array electrode without binder: Synergistic effects of Cu0, Cu+, and Cu2+ during ·O2– generation and sulfamethoxazole degradation

Cu-based nanocatalysts have received much attention for their high efficiency and environmental friendliness in heterogeneous electro-Fenton (hetero-EF) technology. However, designing catalysts posses high stability and efficient pollutant degradation performance remains challenging. In this work, a novel binder-free copper foam (CF)-supported CuxO nanorod array electrode was prepared by solvothermal and calcination methods and used for the degradation of sulfamethoxazole (SMX). The hetero-EF system with CuxO NRs/CF-300 °C as cathode achieved 100 % SMX degradation in 90 min. Experimental and theoretical calculations showed that the coexistence of Cu0, Cu+, and Cu2+ in Cu-based catalysts promotes the generation of ·O2– and facilitates redox cycling of Cu species (Cu+/Cu2+), thus enhancing SMX degradation efficiency. In addition, CuxO NRs/CF-300 °C expanded the pH range (3–11) and exhibited remarkable stability, making it an excellent synthetic electrode material with production potential. This discovery successfully overcame the low and unstable Cu+ activation capacity and the short lifetime of reactive oxygen species in conventional heterogeneous reactions. This work provides a practical approach for developing reliable Cu-based nanocatalysts and facilitating the degradation of organic contaminants.