Ultrafast H-Spillover in Intermetallic PtZn Induced by the Local Disorder for Excellent Electrocatalytic Hydrogen Evolution Performance.

Ordered intermetallic Platinum-Zinc (PtZn) shows potential in hydrogen evolution reaction (HER), but faces a huge challenge in activity enhancement due to the H-repulsion properties of Zinc (Zn). Here, local disorder in ordered intermetallic PtZn nanoparticles confined in N-doped porous carbon (I-PtZn@NPC) via a confinement-high-temperature pyrolysis strategy is realized to boost the HER performance. Experiments and calculations demonstrate that the local substitution of Pt atoms for Zn atoms creates an ultra-short H-spillover channel (Pt site→Pt-Zn bridge site →Zn site). Benefiting from such an ultra-fast H-migration from Pt site to Zn site, I-PtZn@NPC exhibits enhanced intrinsic activity with an ultralow overpotential (η: 2.3 mV, η: 24 mV) than commercial Pt black catalyst. Furthermore, a 25 cm commercial proton exchange membrane (PEM) electrolyzer equipped with I-PtZn@NPC achieved stable operation at 1.60 V for 200 h at a current density of 1 A cm⁻. This design of local Zn disorder in the ordered intermetallic PtZn sheds new light on the rational development of efficient Zn-based alloy HER electrocatalysts.