Nonradical oxidative degradation of amino-G acid by hydrogen peroxide induced by copper cerium plate catalyst: Electron transfer mechanisms

Advanced oxidation processes based on nonradical oxidation pathways have become promising pollutant removal methods because of their selectivity and adaptability. In this study, three ceria with different morphologies were synthesized: plate (p-CeO2), rod (r-CeO2), and cubic (c-CeO2). p-CeO2 was observed to have the highest activity for hydrogen peroxide (H2O2) decomposition. Cu doping further improved the catalytic activity of p-CeO2 for H2O2 decomposition compared to other metals, such as Mn, Co, Cu, and Zn. The plate copper-ceria material (p-Cu/CeO2-3) activated the H2O2 and completely degraded amino-G acids (10 mg L-1) within 90 min under optimal conditions (0.3 g L-1 p-Cu/CeO2-3, 5 mM H2O2). Through a comprehensive study of the scavenging and pretreatment experiment, electron paramagnetic resonance (EPR), and in situ Raman spectroscopy, it was proven that the catalytic oxidation of amino-G acid on p-Cu/CeO2-3 was mainly mediated by an electron transfer mechanism center dot H2O2 can be absorbed on the surface of p-Cu/CeO2-3 to form the Ce-hydrogen peroxide surface complex ( Ce(III)- center dot OOH), which can act as an electron acceptor when the amino G acid is in close proximity to the complex. In addition, p-Cu/CeO2-3 showed excellent catalytic performance over a wide pH range (3-9). This study provides a new system for the degradation of amino-G acid through electron transfer pathways.