Trace tiny NiCo alloy nanoparticles encapsulated on hierarchical porous peanut-like carbon walls for robust oxygen evolution reaction

The fine regulation of the porous structure and morphology of biomass-like carbon is a promising strategy to realize rapid catalytic reaction kinetics. Herein, we report a universal hydrothermal method to manipulate metal ions (Ni²⁺, Co²⁺, and Fe³⁺) into peanut-like carbon (pC) derived from sucrose. Furthermore, a simple pyrolysis strategy is developed to finely manipulate the porous structure of pC to realize the hierarchical porous structure, large specific surface area, and abundant defects of NiCo@mpNC catalyst, in which highly dispersed trace NiCo alloy nanoparticles are encapsulated with N-doped pC. Particularly, N-doped porous pC consists of massive ultrathin carbon walls, which restrict the growth of tiny NiCo alloy nanoparticles. Therefore, the fabricated NiCo@mpNC inherits superior oxygen evolution reaction (OER) activity with a low overpotential of 278 mV (vs. RHE) at a current density of 10 mA cm⁻². Moreover, NiCo@mpNC enables robust electrocatalytic stability (≥ 20 h) at a multi-scale current density of 10, 20, and 50 mA cm⁻². The potential decays by only 8 mV after 3000 cyclic voltammetry (CV) cycles. This work opens up a feasible way for the fine design of biomimetic carbon matrix with hierarchical porous structure as typical carriers for high-efficient OER catalysts.