Electrochemically In Situ Formed Active and Stable Surface Gradient Layer on Amorphous Ni‐La‐S‐O Catalyst for Efficient Hydrogen Evolution From Alkaline Seawater

ABSTRACT

The complex corrosive environment and interference from impurity ions in seawater present significant challenges for developing high‐performance hydrogen evolution reaction (HER) electrocatalysts. Herein, amorphous Ni‐La‐S‐O materials were developed in conjunction with an in situ electrochemical activation strategy to advance this field. Specifically, through chronopotentiometry at –2500 mA cm ⁻² (CP2500), the amorphous Ni‐La‐S‐O catalysts exhibit significantly enhanced HER performance accompanied by surface reconstruction processes, leading to an in situ formed active and stable 5 µm‐thick surface gradient layer after CP2500‐2 h. Remarkably, the optimal activated Ni‐La‐S‐O (6‐1) sample demonstrates superior corrosion‐resistant and electrocatalytic performance, requiring overpotentials of only 158 and 226 mV to achieve industrial‐level HER current densities of 1000 and 2000 mA cm ⁻² in alkaline seawater and sustaining stable operation at 1000 mA cm ⁻² for over 120 h, significantly outperforming commercial Pt/C and most other reported representative catalysts. Theoretical calculations further reveal that the activation induced by the CP‐processing originates from the optimized d ‐band centers and reduced water dissociation energy barriers of the Ni‐La‐S‐O catalyst via surface reconstruction. This work not only promotes the large‐scale development of seawater electrolysis for hydrogen production but also offers a cutting‐edge perspective on optimizing the performance and investigating the working mechanisms of amorphous catalysts.