Plasma Treatment on 1D Tungsten Disulfide Carbon Core-Shell Composites for Improved Performance in the Hydrogen...

Cold plasma treatment is a cost-effective, energy-efficient method for modifying material surfaces by introducing reactive species that break and reform chemical bonds. In this work, WS₂ nanotubes (NTs) were coated with carbon nanodots to form a 1D carbon-coated WS₂ NTs (AWS₂/C) core-shell structure, followed by radiofrequency plasma treatment; the resulting carbon-coated plasma-treated catalysts exhibit markedly enhanced hydrogen-evolution performance. Plasma treatment modifies the near-surface structure and chemistry of the catalyst. In the carbon-coated system, Ar plasma provides beneficial shallow surface activation, The additional D₂ plasma exposure produces a clear increase in the local (002) interlayer spacing from 0.62 to 0.65 nm accompanied by stronger lattice disorder. Compared with untreated AWS₂/C (328 mV at -10 mA/cm²), Ar plasma treated AWS₂/C (AWS₂/C-Ar) samples show a significantly reduced overpotential of 168 mV, whereas AWS₂/C-Ar-D₂ is less active despite its larger structural perturbation. This behavior contrasts with our earlier findings on pristine WS₂ NTs, where combined Ar-D₂ plasma treatment was more beneficial than single-gas plasma process, and, therefore, indicates the carbon shell fundamentally changes the plasma-response mechanism at the WS₂ interface. These newly designed catalysts exhibit good operational stability, highlighting the promise of plasma-engineered carbon-coated WS₂ NTs for hydrogen-evolution electrocatalysis.