Ir-Au Bimetallic Nanoparticle Modified Silicon Nanowires with Ultralow Content of Ir for Hydrogen Evolution Reaction

Reducing the size and increasing the dispersity of the noble metals are effective ways to decrease the dosage and simultaneously increase their electrocatalytic activities for hydrogen evolution reaction (HER). The Ir−Au bimetallic nanoparticle modified silicon nanowires (Ir−Au−Si) with ultralow content of Ir are prepared and served to catalyze HER in the acid condition. The small Ir−Au nanoparticles are in-situ grown and uniformly dispersed on the surface of silicon nanowires. Ir−Au−Si exhibits a significantly increased activity in HER catalysis compared with Ir−Si and Pt−Au−Si. Ir provides the active sites for HER, Au increases the electron transfer rate, and the silicon nanowires improve the speed of the hydrogen gas evolution. The optimal Ir−Au−Si-2 shows a low Tafel slope of 24 mV dec ⁻¹ and high mass activity, which are better than those of Ir−Si and Pt−Au−Si catalysts.