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

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/Y₂O₃ 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/Y₂O₃ electrode. Construction of Ni/Y₂O₃ 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 H₂ gas bubble release timely, further enhancing the catalytic activity and stability at high current density.