Strong electrostatic adsorption-engaged fabrication of sub-3.0 nm PtRu alloy nanoparticles as synergistic electrocatalysts toward hydrogen evolution

Alloying of Pt with Ru to form ultrafine and well-defined PtRu alloy nanoparticles (NPs) for synergistically electrocatalytic hydrogen evolution is highly desirable but remains a synthetic challenge. Here, we report a strong electrostatic adsorption(SEA)-assisted fabrication of ultrafine and homogeneously distributed PtRu alloy NPs using ethylenediaminetetraacetic acid tetrasodium-derived carbon (EC) as a matrix. The O, N-rich EC with hierarchically macro/meso/microporous structure and the SEA-assisted formation of [Ru(bpy)3][PtCl6] complex ensure the successful generation of ultrasmall PtRu alloy NPs (~2.93 nm in diameter) with high dispersion. The optimal PtRu/EC-700 delivers excellent electrocatalytic properties with an ultralow overpotential (η10=18 mV), robust durability as well as good long-term stability for alkaline hydrogen evolution reaction (HER). The ultrasmall PtRu alloy NPs with rich surface sites, the synergistic catalysis effect between Pt and Ru as well as the hierarchically macro/meso/microporous structure of O, N-rich EC cooperatively enhance the HER performance of PtRu/EC-700. This study provides an easy but effective way to construct metal alloy NPs with an ultrafine size and high dispersity for catalytic applications.