Ultrasmall PdCuMo Nanoparticle Assemblies for Hydrogen Evolution

Pd-based nanostructures have potential use in optronics, sensing, organic catalysis, and gas-involved electrocatalysis. Despite the substantial advances made, controllable synthesis of amorphous-dominated Pd-based ternary alloy nanoparticles or related assemblies still faces challenges, and their uses for the hydrogen evolution reaction (HER) have not been fully studied. Here, the amorphous-dominated ultrasmall PdCuMo nanoparticle (2.58 nm) assemblies are fabricated under mild conditions via a polyether-assisted thermal reduction strategy, which possesses numerous amorphous/crystalline (a/c) heterophase interfaces, mesoporous structures, and a high specific surface area. Due to the presence of unique a/c heterophase interfaces, proper alloy constituents, and their strong interplay that can regulate the surface/interface electronic structure and optimize the Pd–H bonding intensity, the resultant amorphous-dominated PdCuMo assemblies manifest unprecedented HER performance with an ultralow overpotential of 15.6 mV at a current density of 10 mA cm–2 and a high mass activity of 390 A gPd–1 at a potential of −0.05 V vs reversible hydrogen electrode (RHE), outperforming their binary counterparts (PdCu and PdMo), PdCuMo control sample with a relatively high crystallinity (c-PdCuMo), benchmark Pt/C (commercial, 20%), and the state-of-the-art studied Pd-based electrocatalysts. Additionally, such amorphous-dominated PdCuMo assemblies exhibit outstanding durability and high faradic efficiency yet. This work may shed light on designing advanced amorphous-dominated or a/c heterophase Pd-based multicomponent alloy nanostructures or related assemblies for application in water splitting or other important technological fields.