Self-reconstruction of cationic activated Ni-MOFs enhanced the intrinsic activity of electrocatalytic water oxidation

Abstract

Metal–organic frameworks (MOFs) have emerged as alternative OER catalysts due to their alkaline hydrolysis from high “molecular-scale pores” to high “nano-scale porosity” in alkaline solution, and then in situ self-reconstruction from MOFs to metal hydroxides. Herein, quantitative iron ions are spontaneously adsorbed on the surface of Ni-MOFs with negative charge effect and are directly used as OER catalysts. Based on the cation regulation and the in situ alkaline hydrolysis of MOFs in 1.0 M KOH solution, the multilayer bimetallic nickel irons hydroxide with enriched active sites were intended to be the real active phase. At the same time, the introduction of iron cation will also produce a bimetallic synergy, thus achieving superior OER catalytic activity (η₅₀ = 280 mV). This novel strategy provides an avenue for the exploration of catalytic mechanisms and directional design of MOF-based catalysts.