Correlating Structural Disorder in Metal (Oxy)hydroxides and Catalytic Activity in Electrocatalytic Oxygen Evolution

Understanding the correlation between the structural evolution of electrocatalysts and their catalytic activity is both essential and challenging. In this study, we investigate this correlation in the context of the oxygen evolution reaction (OER) by examining the influence of structural disorder during and after dynamic structural evolution on the OER activity of Fe-Ni (oxy)hydroxide catalysts using operando X-ray absorption spectroscopy, alongside other experiments and theoretical calculations. The Debye-Waller factors obtained from extended X-ray absorption fine structure analyses reflect the degree of structural disorder and exhibit a robust correlation with the intrinsic OER activities of the electrocatalysts. The enhanced OER activity of in situ-generated metal (oxy)hydroxides derived from different pre-catalysts is linked to increased structural disorder, offering a promising approach for designing efficient OER electrocatalysts. This strategy may inspire similar investigations in related electrocatalytic energy-conversion systems. Revealing the structural disorder-activity correlation during the structural evolution process in oxygen electrocatalysis is crucial. This study highlights that the reaction-derived Fe-Ni bimetallic (oxy)hydroxide, featuring a more disordered structure by harnessing the bond mismatch between sulphide/selenide pre-catalysts and in situ-derived (oxy)hydroxides, demonstrates enhanced electrocatalytic activity for the oxygen evolution reaction.+image