Selenium induced multicomponent platinum-based ultrathin nanowires with abundant grain boundaries and partial amorphous phase enable remarkable multifunctional electrocatalysis.

Ultrafine platinum (Pt)-based nanowires (NWs) have emerged as a highly promising type of materials for multifunctional electrocatalysts. However, to achieve their synthesis presents significant challenges via relatively facile strategies, especially for multicomponent Pt-based NWs, due to the substantial variation in reduction potentials among different precursors and the tough coordination required for nanocrystal nucleation and growth. Herein, ultrathin NWs composed by Pt, Se, and Cd were realized via a facile one-pot synthesis where only involving precursors, reducing agent and solvent. Moreover, the prepared NWs embed the joint advantages of multicomponent, partial amorphous, ultrafine size, abundant grain boundaries and surface-defect-sites meanwhile. Thus, the ultrahigh methanol oxidation reaction (MOR) activity of 2.94 A mg and superior catalytic stability were achieved for Pt-Se-Cd NWs, transcending the most of Pt-based catalysts. Density functional theory calculation suggests that the outstanding MOR activity was attributed to the weakened CO poisoning and optimized adsorption of *CHOH. Apart from MOR, Pt-Se-Cd NWs are also with remarkable activities for ethanol oxidation reaction (EOR) and hydrogen evolution reaction (HER). Se precursor plays a key role on NWs formation and amorphous regulation, based on which more Pt-Se-M NWs (M = Zn, In, CdZn, ZnIn, CdInZn) were fabricated successfully, revealing a superior generalization in NW synthesis. The work may not only highlight a facile synthesis for ultrafine Pt-based NWs with abundant catalytic advantages, but also explore their potential applications in electrocatalysis and beyond.