Dynamic surface reconstruction engineers interfacial water structure for efficient alkaline hydrogen oxidation

Abstract

Investigating the dynamic evolution of the catalyst and regulating the structure of interfacial water molecules participating in the hydrogen oxidation reaction (HOR) are essential for developing highly efficient electrocatalysts toward the practical application of anion exchange membrane fuel cells. Herein, we report an efficient strategy to activate hexagonal close-packed PtSe catalyst through in situ reconstruction that undergoes dynamic Se leaching and phase transition during linear sweep voltammetry cycles. The obtained Pt–Se catalyst presents as a surface Se atom-modified face-centered-cubic Pt-based nanocatalyst, and it exhibited remarkable catalytic performance in the alkaline HOR, showing an intrinsic activity of 0.552 mA cm⁻² (j^0,s) and a mass activity of 1.084 mA μg⁻¹ (j^k,m @ 50 mV). The experimental results, including in situ surface-enhanced infrared absorption spectroscopy and density functional theory calculations suggest that the accumulated electrons on the surface-decorated Se of Pt–Se can induce the regulation of the interfacial water structure between the electrode and electrolyte surface in the electric double-layer region. Consequently, the migration of OH⁻ species from the electrolyte to the catalyst surface can be apparently accelerated within this disordered water network, which together with the optimized intermediate thermodynamic binding energies, contribute to the enhanced alkaline HOR activity.