Average metal ion electronegativity as a general descriptor for screening Ni-based double hydroxides with high electrocatalytic water oxidation activity

Abstract

A descriptor based on the metal ion electronegativity is designed to screen the optimal Ni-based double hydroxides OER electrocatalyst. • The metal ion electronegativity (MIE) represents the intrinsic chemical property. • A volcano trend for MIE vs OER intrinsic activity of Ni-based DHs is described. • The best DHs in the peak of the volcano plot is Ni 0.8 Co 0.2 DHs (MIE = 1.39). • MIE differences affect the metallic electronic structure in OER activity. • A MIE descriptor is used to rapidly screen the DHs-based electrocatalyst. Due to the multiclass complex processes in the oxygen evolution reaction (OER) by Ni-based double hydroxides (DHs) electrocatalysts, it is necessary to seek a comprehensive assessment to uncover the electrochemical nature. Here, Ni 0.8 M 0.2 DHs and Ni 0.7 M 0.3 DHs nanowires (M = Zn, Co, Fe, Cu) were prepared by a hydrothermal method. As the intrinsic chemical property, metal ion electronegativity (MIE) as the descriptor, the structure–activity relationship between MIE and OER reaction intermediates' adsorption and desorption capacity was researched by the electrochemical impedance analysis. At the top of the volcano trend (MIE = 1.39, Ni 0.8 Co 0.2 DHs), it is screened and exhibits the lowest interfacial charge transfer resistance and the adsorption and desorption resistance of intermediates. This work provides a cost-effective method based on the theory of electronegativity equilibrium for the precise screening and design of high-active OER electrocatalysts.