Modulating surface electron structure of LaMnO3 nanocatalysts for peroxymonosulfate activation by quenching-induced near-surface modification

Abstract

Modifying the surface structure of catalysts is critical for facilitating peroxymonosulfate (PMS) activation. Here, we present a quenching approach to effectively modify the surface chemistry of LaMnO3 nanocatalysts, in which the optimal catalyst obtained by quenching displays higher catalytic degradation performance for levofloxacin (LEVO). The experimental results demonstrates that the increased intrinsic catalytic activity is directly connected to the quenching-induced exposed facets transition and synergistic effect of Cu/Co ions. Meanwhile, density functional theory calculations (DFT) further reveal the aforementioned modifications to surface structure result in an upward shift of d-band centre, which optimizes the adsorption of PMS and makes it easier for the transfer of electron between Mn sites and PMS, thereby facilitating the reduction of Mn4+ and enhancing catalytic activity for PMS activation and LEVO degradation. This study presents new ideas for controlling surface structure of perovskite metal oxide catalysts and broadens applicability of quenching chemistry in heterogeneous catalysis.