Electronic coupling regulation in MOF derived Mn/Fe co-doped Ni2P through Mn/Fe integration for enhanced overall water splitting

Abstract

Modulation of electronic properties in electrocatalysts can optimize and even enrich electronic effects to enhance catalytic performance. The conceptual validation of this strategy can be performed via electrocatalytic water splitting. Herein, a rational design of Mn/Fe co-doped Ni₂P nanoflower arrays derived from a metal–organic framework (MOF) is conceived, which generates favorable thermodynamics and reaction kinetics through the electronic structure modulation and synergistic integration strategy. The surface work function (WF) and X-ray photoelectron spectroscopy (XPS) synergistically manifested that the electronic coupling between Mn, Fe, and Ni cations is well regulated by optimizing the ratio of the metal atoms, thereby adjusting the filling of metal ions to optimize the performance of overall water splitting. As a result, the optimized Mn–Fe–Ni₂P/NF nanoflower exhibits efficient overall water splitting performance, delivering a low overpotential of 231 mV and 288 mV to achieve current densities of 100 mA cm⁻² and 200 mA cm⁻² for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. Specifically, Mn–Fe–Ni₂P/NF as a bifunctional electrocatalyst generates a low cell voltage of 1.54 V at 10 mA cm⁻². The electronic coupling strategy in this study provides a constructive solution for designing MOF derivative catalysts for energy conversion applications.