Regulating d–p Hybridization in Mo-Doped CoP Nanoflowers with Superwetting Surfaces for Water Splitting at 3000 mA cm–2

Abstract

To overcome the low current-density efficiency and long-term stability issues of industrial overall water splitting at ampere-level current density, a kind of superwetting Mo-doped nanoarray anchored on nickel foam (NF) (Mo-CoP/NC) with three-dimensional (3D) nanoflower structure is constructed. The incorporation of Mo species induces thermoneutral hydrogen adsorption free energy and creates favorable empty d-orbitals, which enhances the d–p hybridization of Co–O bonds, thereby accelerating the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics in alkaline media. The optimized Mo-CoP/NC exhibits exceptional electrocatalytic performance, requiring low overpotentials of 198 mV for HER and 384 mV for OER at a current density of 1000 mA cm^–2 and achieving maintains robust operation in overall water splitting at 3000 mA cm^–2. When employed as a bifunctional catalyst in an alkaline electrolyzer, a cell voltage of 1.87 V can be realized at 1000 mA cm^–2 , outperforming commercial benchmarks. Density functional theory (DFT) calculations reveal that Mo doping optimizes hydrogen adsorption energy and reduces energy barriers for water dissociation. The superwetting surface ensures rapid gas bubble detachment and efficient active site regeneration, while N-doped carbon encapsulation endows long-term stability with negligible activity decay over 100 h of continuous operation.