Rational d‐Orbitals Modulation for Tailoring Co2P Interfacial Adsorption Behavior: Boosting Alkaline Hydrogen Evolution

Abstract Rational design of an efficient catalyst that simultaneously accelerates water splitting, promotes hydroxyl conversion, and facilitates hydrogen desorption presents a significant challenge for alkaline hydrogen evolution reaction (HER). To address this challenge, a series of coordinating metals selected from elements of the 4th‐ and 5th‐period is incorporated into dicobalt phosphide (Co 2 P), thereby tuning the interfacial adsorption. Among these elements‐coordinated catalysts, simultaneously considering both d ‐band filling and spin polarization, the iron‐coordinated catalyst (Fe‐CPNCF) exhibits appropriate adsorption energy, activates interfacial inert H 2 O molecules and locates at the optimal position on the volcano plot for the H 2 O dissociation barrier, owing to the rational d ‐orbitals modulation of active sites by Fe coordination. Thus, the anion exchange membrane water electrolyzers based on Fe‐CPNCF achieve a current density of 2 A cm −2 at a low cell voltage of 2.04 V and maintain stable electrolysis for 1160 h, demonstrating great potential in commercial applications. This work underscores the importance of rationally tuning the d‐ orbitals of active sites for modulating interfacial adsorption behavior, providing relevant insights for the development of efficient hydrogen evolution catalysts.