Fe‐Doped NiCoP Prussian Blue Derivatives for Alkaline Electrocatalytic Hydrogen Evolution

Precious metals (e.g., platinum, iridium, etc.) used for electrocatalytic water splitting have excellent performance, but their cost and scarcity are still a concern. The development of low‐cost non‐noble metal catalysts is the key to the future development of hydrogen energy. For enhancing the performance of non‐noble metal catalysts, rational heteroatom doping is a promising approach to promote the catalytic activity for hydrogen evolution reaction (HER). In this article, NiCoP catalysts with varying Fe doping ratio are synthesized via low temperature phosphorization of a simple Prussian blue precursor. 20% Fe‐doped NiCoP catalysts shows outstanding performance (93 mV@10 mA cm −2 , 55.4 mV dec −1 ), achieving stable operation over 48 h under alkaline conditions. In situ Raman test and the characterization after stability test confirm that Fe‐NiCoP is the real HER active species. With immersion in alkaline solution, Fe‐NiCoP surface transforms into its corresponding oxide/hydroxide layer, which indirectly protects the catalyst structure from damage and maintained electrocatalytic stability for a longer period. Theoretical calculations show that the introduction of Fe atoms into NiCoP can reduce the Gibbs free energy of hydrogen adsorption (Δ E H* ). The introduction also increases the metal valence state on the surface of NiCoP and decreases the valence state of P atoms, which reduces the adsorption capacity of P atoms on hydrogen and promotes charge transfer in hydrogen adsorption/desorption process. At the same time, doping makes the adsorption center of P atoms of the p‐band center away from the Fermi level, thus reducing the interaction between P and H atoms. This article provides a practical strategy for doping heteroatoms to modulate the electronic structure and surface charge distribution for more efficient HER catalysts.