Enhancing the structural reconstruction of multicomponent spinel oxide for robust water oxidation

Abstract

Multicomponent spinel oxides have been extensively employed as innovative catalysts in oxygen evolution reaction (OER). An in-depth comprehension of the structural evolution in multicomponent spinel catalysts during the OER process is crucial to elucidate the source of their catalytic activity. In this study, we systematically investigate the structure evolution that occurs in multicomponent spinel (CrFeCoNi)₃O₄ during the OER process. Experimental results show that the Cr leaching under the applied potential enhances the covalency of metal-oxygen bonds, promoting structural reconstruction toward amorphous metal (oxy)hydroxides. Detailed electrochemical analysis further demonstrates that the OER mechanism of (CrFeCoNi)₃O₄ follows the enhanced lattice oxygen mechanism, which is attributed to the formation of highly OER-active phases resulting from structural reconstruction. At 10 mA·cm^-2, the overpotential of (CrFeCoNi)₃O₄ is 283 mV, which is smaller than that of the Cr-free control sample (FeCoNi)₃O₄ and most of the reported spinel oxides.