Selenium-Induced Directional Growth of Ultrathin Nanowires with Subnano Amorphous Shells for High-Performance Multifunctional Electrocatalysis.

Abstract

The fabrication of 1D platinum (Pt)-based ultrafine core-shell nanostructures with controllable morphologies is a potential strategy to maximize atom utilization in electrocatalytic applications. Here, we report a synthesis strategy of selenium (Se)-induced ultrafine Pt nanowires (NWs) with subnano amorphous shells, in which Se could promote the end-to-end directional attachment of shorter PtNi alloy nanowires, covered with PtNiSe_<i>x</i> subnano amorphous shells. The core-shell nanowires exhibit excellent mass activity and stability for the hydrogen evolution (HER), methanol oxidation (MOR), and ethanol oxidation reactions (EOR). Specifically, the as-fabricated PtNi-Se₁ NWs exhibit impressive HER properties with a mass activity of 24.8 A mg_Pt^-1 at -70 mV and pH 14 and an activity loss of only 6% after 1000 h at 400 mA cm^-2 at pH values of both 14 and 0. Practically, the assembled proton exchange membrane electrolyzer delivers a current density of 1 A cm^-2 at a voltage of only 1.806 V and can operate stably for 400 h, showing strong potential for large-scale H₂ production. Moreover, the NWs also display excellent MOR and EOR properties in alkaline media, with mass activities of 9.6 and 4.22 A mg_Pt^-1, respectively. <i>In situ</i> Raman spectra and theory calculations illustrate the optimized hydrogen binding energy on the Pt/Se sites, the significantly lowered activation energy barrier for H₂O dissociation on the Ni sites, and weakened CO* binding, which lead to significantly enhanced HER, MOR, and EOR performances. The results provide a potential strategy for developing efficient and robust noble metal-based catalysts.