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 Ni₂ P-Ni₁₂ P₅ nanorod arrays rooted on Ni₃ S₂ film (Ni₂ P-Ni₁₂ P₅ @Ni₃ S₂ ) 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 Ni₂ P and Ni₁₂ P₅ as well as the robust stabilization of 1D heteronanorod arrays by Ni₃ S₂ 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, Ni₂ P-Ni₁₂ P₅ @Ni₃ S₂ /NF requires only 32, 46, and 34 mV overpotentials to drive 10 mA cm^-2 in 1.0 m KOH, 0.5 m H₂ SO₄ , 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.