Highly efficient degradation of phenol from wastewater via an electro-catalytic oxidation approach with a CeO2-CuO cathode

The development of highly efficient cathode materials for the electro-catalytic oxidation of phenol from wastewater is of vital importance for environment protection. Herein, we develop an effective CeO2-CuO electrocatalyst for 2-electron oxygen reduction reaction (ORR) to generate H2O2, and then applied it as the cathode for the electro-catalytic oxidation of phenol. Results showed that the CeO2-CuO cathode with different contents of CuO exhibited a higher yield of H2O2 than those of CuO and CeO2, and the highest yield of H2O2 (114 mg L-1) was achieved with a CuO content of 13.4%. The resultant CeO2-CuO-13.4% cathode demonstrated a high degradation rate of 91% after 180 min, which was 1.82-fold and 1.52-fold higher than pure CuO (50%) and CeO2 (60%) electrodes, respectively. Furthermore, the degradation rate of phenol via the electro-catalytic oxidation technology by using a CeO2-CuO cathode significantly outperformed that of the chemical oxidation approach. The outstanding degradation performance of the CeO2-CuO cathode is attributed to the high yield of H2O2 and the strong interaction of CeO2 and CuO.