Low-Loading Pt Nanoparticles Anchored on Niobium Nitride for Highly Efficient Alkaline Hydrogen Evolution

Pt-based catalysts remain the premier hydrogen evolution reaction (HER) electrocatalysts for anion-exchange membrane water electrolyzers. Faced with insufficient abundance and high cost, developing low-Pt electrocatalysts that can accelerate the Volmer step while maintaining high durability is critically important yet challenging. Herein, we propose niobium nitrides with excellent conductivity and stability as supports for Pt to enhance the alkaline HER. A polyoxoniobate-based molecular self-assembly strategy was ingeniously designed to fabricate Nb₄N₅ nanospheres, on which ultrafine Pt nanoparticles (NPs) were successfully immobilized, forming Pt/Nb₄N₅ heterostructures (denoted as Pt/Nb₄N₅). The rich interface structures with metal-support interactions drive charge transfer from Pt to Nb₄N₅, which modulates the electronic structure of Pt and Nb sites, collectively lowering interfacial charge transfer resistance, generating abundant active sites, and improving catalyst durability. Consequently, the Pt/Nb₄N₅ catalyst achieves exceptional HER performance, including a low overpotential (22 mV@10 mA cm^-2), a small Tafel slope (26 mV dec^-1), an 11.5-fold higher mass activity at 150 mV, and remarkable durability, drastically surpassing the commercial Pt/C catalyst. Notably, the Pt/Nb₄N₅-based electrolyzer requires only 1.508 V to drive 10 mA cm^-2. This work offers a viable pathway to engineer highly active and durable low-Pt electrocatalysts for energy-related applications.