Electrochemical Reconstruction Engineering: Metal–Organic Gels as Pre‐Catalysts for NiOOH/FeOOH Heterostructure to Boost Oxygen Evolution Reaction

Abstract

Metal–organic gels (MOG) as new types of soft materials have shown promising applications in various fields such as chemosensors, environmental remediation, and gas adsorption/separation, owing to their high porosity, low density, and high surface area. However, the application of MOG materials in energy electrocatalysis and the active components made from them are rarely perceived. Herein, a new electrochemistry‐driven reconstruction strategy to synthesize the NiOOH/FeOOH heterostructure from MOG materials is reported. The reconstructed NiOOH/FeOOH exhibits superior oxygen evolution reaction activity and excellent stability, owing to the synergistic effect of bimetallic centers, the abundant interface between NiOOH and FeOOH, and the plentiful defects. Impressively, the activated Re–FeNi–MOG‐4 electrocatalyst displays remarkable catalytic activity with a low overpotential of 220 mV at a current density of 10 mA cm−2 and a small Tafel slope of 48 mV dec−1 in alkaline electrolyte, outperforming most recently reported electrocatalysts. Herein, a facile and effective electrochemical reconstruction engineering of pre‐catalysts is provided and the evolution of self‐reconstruction of MOG materials for accelerating the kinetics of the electrocatalytic process is highlighted.

Engineering the spin configuration of electrocatalysts for electrochemical renewable conversions

“…Based on the principles of catalyst designs, a large number of works have been summarized on the synergy of the electrocatalytic performance-electron spin activity to further optimize the intrinsic and overall catalytic performance, 45,83–88 such as local lattice mismatch, 2,89 surface/interface regulation 27,90,91 and others. 92–94 In this section, we will discuss the above strategies for regulating the catalyst spin states from the intrinsic magnetic moment of ferromagnetic materials, and further overview the spin electrocatalysis applications of these strategies.…”

“…Interestingly, in the case of FeOOH, the possible Fe 3+ sites enable the OER catalytic activity to be relatively low, which may be attributed to the fact that the oxygen ligands connected to two adjacent iron cations show a relatively low spin density (0.080 e − ) and the long-range spin-related charge transport inside the FeOOH catalyst is poor. 90…”

Research progress on layered metal oxide electrocatalysts for an efficient oxygen evolution reaction

“…30–33 Two-dimensional materials including metal halides, metal oxides, metal hydroxides have attracted much attention due to their significant advantages in exposing multiple active sites. 34–36…”