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

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.