Hollow Ru Nanoparticles for Electrocatalytic Hydrogen Evolution
Caihua Zhang, Fengyan Han
Abstract
The development of highly efficient and robust Pt-free electrocatalysts toward the hydrogen evolution reaction (HER) is facing increasing demand. Herein, we demonstrate a hollow Ru nanostructure (h-RuNP) that is fabricated with an ultrasmall Ru nanoparticle of ∼1.72 nm and is resistant to oxidation. The construction of h-RuNP was done using preformed Ni nanocrystals as reducing agents in dimethylformamide (DMF) without the need of any inert gas atmosphere (such as N2) or stabilizing agents. Studies indicate that both the solvent DMF and the ultrasmall Ru nanoparticles help to prevent the surface oxidation of Ru. The as-synthesized h-RuNP possesses robust catalytic activity toward HER in acidic media, which is superior to that of recently reported pure Ru and Ru-based nanocatalysts and close to that of the commercial 20% Pt/C catalyst. The h-RuNP also exhibits exceptional long-term stability under natural ambient conditions (no nitrogen is added to remove oxygen). The enhanced performance of h-RuNP mainly arose from the strong surface oxidation resistance and antiaggregation effect of unsupported ultrasmall Ru nanoparticles.