Effect of the interaction mode of H2O2 over CuMnO2 surface on •OH generation for efficient degradation of ofloxacin: Activity and mechanism

Most researches focus on design and optimization of heterogeneous Fenton catalyst itself to drive H 2 O 2 decomposition into • OH radicals. In this study, we reported the significant impact of the interaction mode of H 2 O 2 and CuMnO 2 (namely H 2 O 2 occurrence form) on the Fenton-like performance. The interaction mode of H 2 O 2 largely exposed to Cu atom active site (CMH-L) led to a superior ofloxacin (OFX) degradation efficiency of 93% compared with H 2 O 2 middle exposed around the Cu atoms (CMH-M, 84%) and small part exposed around the Cu atoms (CMH-S, 50%). The effect of H 2 O 2 occurrence forms on catalytic activity were confirmed by analyzing their fraction and the relevant rate constant with the correlation was 98%. And the relevant interfacial reaction mechanism was detailed explored based on density functional theory calculation, a series of probe experiments and quantitative analysis of H 2 O 2 utilization efficiency and • OH generation. It revealed that Cu atom arrangement on CuMnO 2 can induce the different H 2 O 2 occurrence form, and compared with CMH-M especially CMH-S (1.486 and 1.591 Å), CMH-L has the shortest elongation of O-O bond (1.477 vs. 1.468 Å in free H 2 O 2 ) together with the smallest O-H 1 and O-H 2 (0.988, 1.022 Å), which were more likely to decomposition H 2 O 2 into • OH, while it was more likely to inefficient transformation H 2 O 2 into O 2 in CMH-S system. Thus, this work provided a new insight for improving the heterogeneous Fenton catalytic performance via altering the interaction mode of H 2 O 2 and catalyst, which should be the fundamental reason for efficient H 2 O 2 activation into O 2 or • OH.