Mirror‐Symmetric Nanoarray Networks of Atomic Ni‐Incorporated Tungsten Oxynitride for Efficient and Robust Alkaline Hydrogen Evolution

Abstract

Abstract The development of alkali‐efficient hydrogen evolution reaction (HER) electrocatalysts is essential for future deployment of anion‐exchange membrane water electrolysis technology. Herein, we report a novel heteroatom‐induced strategy to construct the mirror‐symmetric nanoarray networks of Ni‐doped WO 3 on carbon cloth and design a corresponding new type of atomic Ni‐incorporated tungsten oxynitride (Ni‐WNO) electrocatalyst for alkaline HER. Impressively, the Ni‐WNO shows high activity (−35 mV at −10 mA cm −2 ), small Tafel slope (32 mV dec −1 ) and excellent stability (>1200 h at −1.0 A cm −2 ), representing the best‐performing W‐based electrocatalyst for alkaline HER. Multiple spectroscopy characterizations reveal that Ni‐WNO is highly active for adsorbing aggressive OH − /H 2 O groups, resulting in the in situ formation of lattice hydroxyl (i.e., W−OH) species with Brønsted acidity, which, we disclose for the first time, can serve as a mediator to alter the generation of metal−H intermediates from a conventional sequential to a concerted proton−electron transfer (CPET) pathway, thus breaking the pH‐dependent limitations in proton‐deficient alkalies. Further isotope experiments demonstrate that the surface‐mediated H−H coupling can be feasibly accelerated on atomic W−Ni units, thereby enabling Ni‐WNO catalyzing alkaline HER via a new kinetically fast CPET–Tafel pathway.