Enhanced electrochemical advanced oxidation on boride activated carbon: The influences of boron groups

Exploring an efficient electro-catalyst is fundamentally important to enhance degradation of persistent organic pollutants during electrochemical advanced oxidation process. In this work, boride activated carbon (BAC) containing different boron group content was prepared as low-cost and efficient catalysts. BAC possessed a more positive onset potential of oxygen reduction reaction (0.458 V vs. RHE) and a faster rate of H2O2 generation (365 mg/L pH=3), compared with activated carbon (0.425 V vs. RHE, 138 mg/L pH=3). DFT calculations and XPS results revealed that -BC3 and -BC2O active groups enhanced oxygen adsorption, and small electronegativity difference between B and O facilitated the desorption of •OOH. The rate of in-situ phenol degradation (0.193 min−1) increased by an order of magnitude as compared to activated carbon (0.018 min−1), because BAC promoted the in-situ conversion of H2O2 to •OH. Therefore, it provided a theoretical base for the further application of boron catalyst in two-electron oxygen reduction process.