Enhancing cationic superexchange interaction via adjustive lattice distortion in cobalt-based perovskite for improved Fenton-like decontamination

Abstract

The cooperative mechanism of mixed transition metals (TMs) for heterogeneous peroxymonosulfate (PMS) based water treatment can be considered in the viewpoint of cationic superexchange interaction. Herein, Co-Fe cooperation towards PMS activation was studied by modulating octahedral TMO6 units in Fe-substituted LaCo1−xFexO3 perovskites. Certain lattice distortion formed at these reactive centers due to Co-Fe ionic radii mismatch, while LaCo0.95Fe0.05O3/PMS (0.136 min−1) achieved superior performance for iohexol degradation. Cobalt cations are identified as active sites by targeted poison and spectroscopic measurements, which prefer to accept electrons from Fe ions. Experimental and theoretical investigations illustrate that slight Fe-substitution induced lattice distortion leads to Co-O-Fe superexchange interaction, facilitating interfacial electron transfer and cationic valence exchange. And, the tolerance factor of catalysts is also indicated as an indicative descriptor to evaluate structure-dependent performance. Our work attempts to shed light on dual TM interactions for synergistic catalysis towards efficient Fenton-like decontamination.