Sequential Phase Conversion‐Induced Phosphides Heteronanorod Arrays for Superior Hydrogen Evolution Performance to Pt in Wide pH Media

Abstract Developing an efficient and non‐precious pH‐universal hydrogen evolution reaction electrocatalyst is highly desirable for hydrogen production by electrochemical water splitting but remains a significant challenge. Herein, a hierarchical structure composed of heterostructured Ni2P‐Ni12P5 nanorod arrays rooted on Ni3S2 film (Ni2P‐Ni12P5@Ni3S2) via a simultaneous corrosion and sulfidation is built followed by a phosphidation treatment toward the metallic nickel foam. The combination of theoretical calculations with in/ex situ characterizations unveils that such a unique sequential phase conversion strategy ensures the strong interfacial coupling between Ni2P and Ni12P5 as well as the robust stabilization of 1D heteronanorod arrays by Ni3S2 film, resulting in the promoted water adsorption/dissociation energy, the optimized hydrogen adsorption energy, and the enhanced electron/proton transfer ability accompanied with an excellent stability. Consequently, Ni2P‐Ni12P5@Ni3S2/NF requires only 32, 46, and 34 mV overpotentials to drive 10 mA cm−2 in 1.0 m KOH, 0.5 m H2SO4, and 1.0 m phosphate‐buffered saline electrolytes, respectively, exceeding almost all the previously reported non‐noble metal‐based electrocatalysts. This work may pave a new avenue for the rational design of non‐precious electrocatalysts toward pH‐universal hydrogen evolution catalysis.