Navigating surface reconstruction of spinel oxides for electrochemical water oxidation

Understanding and mastering the structural evolution of water oxidation electrocatalysts lays the foundation to finetune their catalytic activity. Herein, we demonstrate that surface reconstruction of spinel oxides originates from the metal-oxygen covalency polarity in the M-T-O-M-O backbone. A stronger M-O-O covalency relative to M-T-O covalency is found beneficial for a more thorough reconstruction towards oxyhydroxides. The structure-reconstruction relationship allows precise prediction of the reconstruction ability of spinel pre-catalysts, based on which the reconstruction degree towards the in situ generated oxyhydroxides can be controlled. The investigations of oxyhydroxides generated from spinel pre-catalysts with the same reconstruction ability provide guidelines to navigate the cation selection in spinel pre-catalysts design. This work reveals the fundamentals for manipulating the surface reconstruction of spinel pre-catalysts for water oxidation. Precise control of water oxidation activity calls for the mastery of surface reconstruction of electrocatalysts. Here, the authors identify the structural origin of surface reconstruction on spinel oxides and report a criterion to evaluate the reconstruction degree, which enable the design of spinel pre-catalyst with controlled reconstruction ability.

Automated summary

In this study, the relationship between surface reconstruction of spinel electrocatalysts and metal-oxygen covalency polarity was investigated. It was found that a stronger metal-oxygen covalency contributes to a more thorough surface reconstruction towards oxyhydroxides. The researchers also developed a criterion to evaluate the reconstruction degree and provide guidelines for cation selection in spinel pre-catalyst design.