Subsize Ru nanoparticles embedded in porous carbon with highly metallic surface enable efficient hydrogen evolution

Ruthenium has regards as a potential electrocatalyst candidate towards hydrogen evolution reaction (HER) to substitute platinum and its surface property regulation is vital for increasing catalytic activity to realize the wide industrialization. Herein, we report a simple and facile method to regulate the metallic surface of Ru nanoparticles through high temperature calcination without particle overgrowth. The nanopores in Ketjenblack EC-600JD are employed as nanoreactors with Ru precursor ultrasonicated and impregnated and the subsize Ru nanoparticles embedded in porous carbon with highly metallic surface are obtained by high temperature annealing. The as-prepared Ru@KB-900 electrocatalyst shows excellent catalytic activity for HER with the overpotentials reached 9.9 mV and 28 mV at the current density of 10 mA cm −2 and the mass activities of 7404 A g Ru −1 and 478 A g Ru −1 at the overpotential of 50 mV, in acidic and alkaline electrolytes, respectively, which outperformed that of commercial Pt/C catalyst in the corresponding conditions. Furthermore, it also delivers a very good life-span performance at the overpotential of 50 mV over 48 h. The high HER activity is ascribed to the highly metallic surface of active site tuned by calcination temperature and the efficient exposure of active sites for the ultrasmall particle size. This study provides a simple and effective method for designing highly active sites with efficient exposure.