Hexagonal Nickel as a Highly Durable and Active Catalyst for Hydrogen Evolution
Zhisen Li, Xiaojian Wen, Fengjiao Chen, Qiuyue Zhang, Qinghua Zhang, Lin Gu, Jun Cheng, Binghui Wu, Nanfeng Zheng
Abstract
The development of highly active and stable earth-abundant electrocatalysts is crucial for the large-scale electrocatalytic hydrogen production. We report herein a crystal-phase heterostructured Ni catalyst with an interior backbone of the face-centered cubic phase covered by a thin surface layer of the hexagonal close packing (hcp) phase. Systematic studies reveal that, upon oxidation, the surface hcp Ni is capable of forming a leaky oxidized layer with abundant Ni0 sites buried underneath. Such underneath Ni0 sites could act synergistically with the leaky surface (hydr)oxide layer from hcp Ni to promote H+ electroreductive formation of H2. The unique surface chemical properties of hcp endow the as-prepared Ni catalyst with high hydrogen evolution activity (112 mV @ 100 mA cm–2) and incredible environment stability even under high current densities and high-concentration alkaline conditions (4–6 M KOH), making it a promising alternative to noble metal catalysts for practical applications in commercial alkaline electrolyzers.