Selectively Dispersed Ruthenium Nanoparticles on WS 2 Nanosheets Fabricated With Plasma Exfoliation and In Situ Polyol‐Reduction as Electrocatalysts for Enhanced Hydrogen Evolution Reaction

ABSTRACT Selectively dispersed Ru nanoparticles (NP ∼3 nm) on WS 2 nanosheets (NS) (WS 2 @Ru) are synthesized by a two‐step strategy—plasma exfoliation of bulk WS 2 into nanosheets and subsequent in situ polyol reduction. The dispersion of Ru NP near WS 2 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. WS 2 @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 WS 2 NS (283 mV and 146 mV dec −1 ), and WS 2 @Ru3 retains excellent stability after 1000 cycles. DFT calculations also show lower Gibbs free energies of hydrogen adsorption (−0.21 eV) at WS 2 @Ru3 edge sites, indicating favorable HER. These enhancements are attributed to the synergistic interaction between Ru NP and WS 2 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.