Surface-Plasmon-Mediated Alloying for Monodisperse Au–Ag Alloy Nanoparticles in Liquid

Abstract

Plasmonic noble-metal nanoparticles with broadly tunable optical properties and catalytically active surfaces offer a unique opportunity for photochemistry. Resonant optical excitation of surface-plasmon generates high-energy hot carriers, which can participate in photochemical reactions. Although the surface-plasmon-driven catalysis on molecules has been extensively studied, surface-plasmon-mediated synthesis of bimetallic nanomaterials is less reported. Herein, we perform a detailed investigation on the formation mechanism and colloidal stability of monodisperse Au−Ag alloy nanoparticles synthesized through irradiating the intermixture of Au nanochains and AgNO 3 solution with a nanosecond pulsed laser. It is revealed that the Ag atoms can be extracted from AgNO 3 solution by surface-plasmon-generated hot electrons and alloy with Au atoms. Particularly, the obtained Au− Ag alloy nanoparticles without any surfactants or ligands exhibit superior stability that is confirmed by experiments as well as DLVObased theoretical simulation. Our work would provide novel insights into the synthesis of potentially useful bimetallic nanoparticles via surface-plasmon-medicated alloying.

Laser Irradiation-Induced Pt-Based Bimetallic Alloy Nanostructures without Chemical Reducing Agents for Hydrogen Evolution Reaction

“…Based on these results, it can be confirmed that the PtAg alloys consist mostly of metallic Pt and Ag. at 367.7 and 373.8 eV were ascribed to metallic Ag 0 [36]. In addition, in Figure S1d, the auger electron spectrum of Ag for the PtAg alloys further confirmed the existence of metallic Ag in the PtAg alloys [37].…”

“…Through XPS analysis in Figure 2a, the observed peaks at 71.1 and 74.4 eV corresponded to metallic Pt 0 in the PtAg alloys but showed a negative shift compared to Pt, suggesting a charge transfer between Ag and Pt via electron interactions, which corresponded to their Pauling electronegativity scale [35]. In Figure 2b, the peaks at 367.7 and 373.8 eV were ascribed to metallic Ag 0 [36]. In addition, in Figure S1d, the auger electron spectrum of Ag for the PtAg alloys further confirmed the existence of metallic Ag in the PtAg alloys [37].…”