Electronic structure modulation of Fe-Ni₂P@CoP heterojunction for efficient industrial water electrolysis toward hydrogen production

Using anion exchange membrane water electrolysis (AEMWE) technology to produce hydrogen is one of the effective pathways for future energy development. Designing efficient and stable anode oxygen evolution reaction (OER) catalysts is crucial for improving hydrogen production efficiency. In this study, Fe-doped Ni₂P material was designed using a MOF as a precursor, and then combined with CoP nanowire arrays to form Fe-Ni₂P@CoP heterojunction composite. Different from previous reports, this work features precise Fe doping (~3.6 at%), a unique 0D/1D morphology, and systematic AEMWE evaluation at 1.0 A cm^-2. It is found that doping and interface engineering induce charge transfer between Fe atoms and the heterojunction interfaces, optimizing the overall electronic structure and enhancing the adsorption of reaction intermediates at the active sites, thereby improving electrocatalytic performance. The Fe-Ni₂P@CoP catalyst demonstrates highly efficient OER activity and requires only 276 mV overpotential to achieve a current density of 100 mA cm^-2, maintaining stability for 100 hours. Subsequently, it is assembled with Pt/C into an AEM electrolyzer, achieving a cell voltage of only 1.77 V at a high current density of 1.0 A cm^-2 relevant to industrial applications, demonstrating promising potential for industrial hydrogen production under specific AEMWE operating conditions.