Electro-Fenton Degradation of Rhodamine B Based on a Composite Cathode of Cu2O Nanocubes and Carbon Nanotubes

In this study, rhodamine B (RhB) in aqueous solution was effectively degraded by an electro-Fenton (E-Fenton) system with a novel oxygen-fed gas diffusion electrode. This electrode was prepared by combining Cu 2 O nanocubes and multiwall carbon nanotubes with poly tetrafluoroethylene (Cu 2 O/CNTs/PTFE). The resulting Cu 2 O nanocubes and Cu 2 O/CNTs/PTFE composite cathode were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and transmission electron microscopy (TEM). The degradation of RhB in this E-Fenton system reached 80.2% and 89.3% in 120 min at neutral pH and pH 3, respectively. A pseudofirst-order kinetics was observed for the degradation of RhB in this E-Fenton system. We studied the factors affecting the degradation of RhB with Cu 2 O/CNTs/PTFE composite cathodes in detail, and detected hydrogen peroxide electro-generated through the reduction of O 2 adsorbed on the cathode and copper ions produced by the slow leakage of Cu 2 O nanocubes. Cyclic voltammetry (CV) experiments revealed that a two-electron reversible redox reaction happened on the Cu 2 O/CNTs/PTFE cathode in this new E-Fenton system. More importantly, we found the Cu 2 O/CNTs/PTFE cathode was very stable and could be reused without catalytic activity decrease, suggesting its potential in the wastewater treatment.