Selectively Dispersed Ruthenium Nanoparticles on WS₂ Nanosheets Fabricated With Plasma Exfoliation and In Situ...

Selectively dispersed Ru nanoparticles (NP ∼3 nm) on WS₂ nanosheets (NS) (WS₂@Ru) are synthesized by a two-step strategy-plasma exfoliation of bulk WS₂ into nanosheets and subsequent in situ polyol reduction. The dispersion of Ru NP near WS₂ NS edges is confirmed with transmission electron microscopy and predicted with a much larger binding energy for Ru NP on edges than on basal planes (-11.01 vs. -8.41 eV) with density function theory (DFT) calculation. X-ray absorption near-edge spectroscopy reveals electron transfer from Ru to W. WS₂@Ru3 (6 wt.% Ru NP) sample shows optimal hydrogen evolution reaction (HER) activity with an overpotential of 83 mV at 10 mA cm^{- 2} and a Tafel slope of 56 mV dec^-1, significantly smaller than those of pristine WS₂ NS (283 mV and 146 mV dec^-1), and WS₂@Ru3 retains excellent stability after 1000 cycles. DFT calculations also show lower Gibbs free energies of hydrogen adsorption (-0.21 eV) at WS₂@Ru3 edge sites, indicating favorable HER. These enhancements are attributed to the synergistic interaction between Ru NP and WS₂ nanosheets that modulates the electronic structure at the active sites. Our approach of creating a selectively-dispersed 0D/2D heterostructure offers a sustainable and scalable strategy for fabricating superior electrocatalysts for hydrogen production.