Surface Facet of CuFeO2 Nanocatalyst: A Key Parameter for H2O2 Activation in Fenton-Like Reaction and Organic Pollutant Degradation

The development of efficient heterogeneous Fenton catalysts is mainly by trial-and-error concept and the factor determining H2O2 activation remains elusive. In this work, we demonstrate that suitable facet exposure to elongate O-O bond in H2O2 is the key parameter determining the Fenton catalyst's activity. CuFeO2 nanocubes and nanoplates with different surface facets of {110} and {012} are used to compare the effect of exposed facets on Fenton activity. The results indicate that ofloxacin (OFX) degradation rate by CuFO2 {012} is four times faster than that of CuFeO2 {110} (0.0408 vs 0.0101 min(-1)). In CuFeO2 {012}-H2O2 system, OFX is completely removed at a pH range 3.2-10.1. The experimental results and theoretical simulations show that (OH)-O-center dot is preferentially formed from the reduction of absorbed H2O2 by electron from CuFeO2 {012} due to suitable elongation of 0-0 (1.472 angstrom) bond length in H2O2 . By contrast, the O-O bond length is elongated from 1.468 to 3.290 angstrom by CuFeO2 {110} facet, H2O2 tends to be dissociated into -OH group and passivates {110} facet. Besides, the new formed Fe2+* on CuFeO2 {012} facet can accelerate the redox cycle of Cu and Fe species, leading to excellent long-term stability of CuFeO2 nanoplates.