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

Abstract

Binary metallic alloy nanomaterials (NMs) have received significant attention because of their widespread application in photoelectrocatalysis, electronics, and engineering. Although various synthetic methods have been adopted to prepare binary alloy NMs, the formation of bimetallic alloy NMs by irradiating the mixed solutions of metal salts and metal powders, using a nanosecond pulsed laser in the absence of any reducing agent, is rarely reported. Herein, we report a simple method to fabricate PtX (X = Ag, Cu, Co, Ni) alloy NMs by laser irradiation. Taking PtAg alloys as an example, we present the growth dynamics of the PtAg alloys by laser irradiating a mixture solution of bulk Pt and AgNO3. The experimental process and evidenced characterization indicate that the photothermal evaporation induced by laser irradiation can cause the fragmentation of the bulk Pt into smaller parts, which alloy with Ag atoms extracted from Ag+ by solvated electrons (e−aq) and free radicals (Haq). These alloys were used as electrocatalysts for the hydrogen evolution reaction (HER), proving their potential application. Notably, in a 0.5 M H2SO4 solution, the PtNi alloy exhibited higher HER activity (44 mV at 10 mA/cm−2) compared to the untreated bulk Pt (72 mV). Our work provides unique insights into the growth processing of valuable Pt-based bimetallic alloy NMs by laser-assisted metallic alloying, which paves a path for the development of bimetallic alloy electrocatalysts.