In this section
@article{Wang:2026:10.1002/adma.74591,
author = {Wang, Y and Ender, E and Kumar, S and Tseng, C and Yang, G and Ye, B and Liang, C and Yu, Y and West, N and Chauhan, I and Ng, JH and Halder, S and Ji, SG and Held, G and Ryan, MP and Moore, KL and Walton, AS and Rao, RR},
doi = {10.1002/adma.74591},
journal = {Adv Mater},
title = {Active Phase of Nickel Electrocatalysts Driving Alkaline Hydrogen Evolution.},
url = {http://dx.doi.org/10.1002/adma.74591},
year = {2026}
}
TY - JOUR
AB - Nickel-based cathodes are widely used in alkaline water electrolysis, yet the nature and stability of the active surface under operating conditions remains unclear. In particular, the role of metal/oxo-hydroxo interfacial structures in governing hydrogen evolution activity is not well understood. Here, we employ a multimodal, depth-sensitive approach combining operando Ni L-edge X-ray absorption spectroscopy, depth-sensitive X-ray absorption measurements in total electron yield and Auger electron yield modes, X-ray photoelectron spectroscopy, isotopically labeled nano secondary ion mass spectrometry, and online electrochemical mass spectrometry to directly track the evolution of Ni/NiOxHy interfaces during the hydrogen evolution reaction. Using well-defined sputtered Ni thin films as a model system, we show that progressive reduction of near-surface oxide/hydroxide species is accompanied by a gradual loss of hydrogen evolution activity. Depth-resolved measurements reveal a predominantly metallic outermost surface under cathodic bias, while NiOxHy forms on the surface upon relaxation to open-circuit conditions. Importantly, mild anodic pre-conditioning regenerates subsurface NiOxHy species, resulting in a sustained increase in hydrogen evolution activity upon subsequent cathodic polarization. These results establish the crucial role of metal/oxo-hydroxo interfaces as active phases for hydrogen evolution and provide a framework for engineering robust, Earth-abundant HER cathodes capable of operating under dynamic, real-world electrolysis conditions.
AU - Wang,Y
AU - Ender,E
AU - Kumar,S
AU - Tseng,C
AU - Yang,G
AU - Ye,B
AU - Liang,C
AU - Yu,Y
AU - West,N
AU - Chauhan,I
AU - Ng,JH
AU - Halder,S
AU - Ji,SG
AU - Held,G
AU - Ryan,MP
AU - Moore,KL
AU - Walton,AS
AU - Rao,RR
DO - 10.1002/adma.74591
PY - 2026///
TI - Active Phase of Nickel Electrocatalysts Driving Alkaline Hydrogen Evolution.
T2 - Adv Mater
UR - http://dx.doi.org/10.1002/adma.74591
UR - https://www.ncbi.nlm.nih.gov/pubmed/42590858
ER -