摘要
Selectively dispersed Ru nanoparticles (NP similar to 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.