Multi‐Interface Engineering of Self‐Supported Nickel/Yttrium Oxide Electrode Enables Kinetically Accelerated and Ultra‐Stable Alkaline Hydrogen Evolution at Industrial‐Level Current Density

Abstract The development of highly active and robust non‐noble‐metal electrocatalysts for alkaline hydrogen evolution reaction (HER) at industrial‐level current density is the key for industrialization of alkaline water electrolysis. Herein, a superhydrophilic self‐supported Ni/Y 2 O 3 heterostructural electrocatalyst is constructed by a high‐temperature selective reduction method, which demonstrates excellent catalytic performance for alkaline HER at high current density. Concretely, this catalyst can drive 10 mA cm −2 at a low overpotential of 61.1 ± 3.7 mV, with a low Tafel slope of 52.8 mV dec −1 . Moreover, it also shows outstanding long‐term durability at high current density of 1000 mA cm −2 for 500 h in 1 m KOH, evidently exceeding the metallic Ni and Pt/C(20%) catalysts. The superior HER activity can be attributed to the multi‐interface engineering of the Ni/Y 2 O 3 electrode. Construction of Ni/Y 2 O 3 heterogeneous interface with dual active sites lowers the energy barrier of water dissociation and optimizes the hydrogen adsorption energy, thus synergistically accelerating the overall HER kinetics. Also, its superhydrophilic self‐supported electrode structure with the firm electrocatalyst‐substrate interface and weakened electrocatalyst‐bubble interfacial force ensures rapid charge transfer, prevents catalyst shedding, and expedites the H 2 gas bubble release timely, further enhancing the catalytic activity and stability at high current density.