Plasma Treatment on 1D Tungsten Disulfide Carbon Core–Shell Composites for Improved Performance in the Hydrogen Evolution Reaction

ABSTRACT 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, WS 2 nanotubes (NTs) were coated with carbon nanodots to form a 1D carbon‐coated WS 2 NTs (AWS 2 /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 D 2 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 AWS 2 /C (328 mV at −10 mA/cm 2 ), Ar plasma treated AWS 2 /C (AWS 2 /C‐Ar) samples show a significantly reduced overpotential of 168 mV, whereas AWS 2 /C‐Ar‐D 2 is less active despite its larger structural perturbation. This behavior contrasts with our earlier findings on pristine WS 2 NTs, where combined Ar‐D 2 plasma treatment was more beneficial than single‐gas plasma process, and, therefore, indicates the carbon shell fundamentally changes the plasma‐response mechanism at the WS 2 interface. These newly designed catalysts exhibit good operational stability, highlighting the promise of plasma‐engineered carbon‐coated WS 2 NTs for hydrogen‐evolution electrocatalysis.