Atomic Disorder Enables Superior Catalytic Surface of Pt-Based Catalysts for Alkaline Hydrogen Evolution

Abstract

Crystalline Pt catalyst for alkaline hydrogen evolution reaction (HER) catalysis is essentially hindered by the slow water dissociation kinetics, originated from the almost full-filled d orbitals and limited numbers of the coordination-unsaturated sites. Breaking the symmetrical atomic arrangements is theoretically feasible to solve this issue, but technically challenging. Herein, surface-disordered Pt–Ni nanowires (d-Pt–Ni NWs) are synthesized via a lithiation/delithiation method. The d-Pt–Ni NWs exhibit an ultralow overpotential of 15 mV at 10 mA cm–2 for HER catalysis, substantially superior to the crystalline counterpart and commercial Pt/C. Fine structural analyses reveal that the structural disorder can well regulate the electronic structures of Pt–Ni and the generated oxygenated nickel species contribute to stabilize the disordered structures. Furthermore, theoretical studies unravel that the oxygenated nickel with lower unoccupied orbitals helps facilitate water dissociation, while the upshift of the d band center of Pt enables superior H adsorption. More importantly, surface disordering is finally demonstrated to be a universal strategy to boost the HER activities of Pt-based alloys. Manipulating the surface atomic arrangement offers a new opportunity to design and optimize Pt-based catalysts and beyond.