Phosphorus doped few layer WS₂ flakes grown by chemical vapor deposition for hydrogen evolution reactions

Water splitting is a promising pathway for hydrogen production, providing an environmentally friendly fuel source. More recently, great attention has been given to transition metal dichalcogenides (TMDCs) because of their interesting chemical and physical properties. In particular, tungsten disulfide (WS₂) has garnered significant attention as a catalyst for this application due to its unique layered 2D structure. In this study, few-layered WS₂ and phosphorus-doped WS₂ (WS₂/P) nanoflakes are synthesized on SiO₂/Si substrates as electrocatalysts for hydrogen evolution reactions (HER) in acidic conditions. Analyses of the synthesized WS₂ and WS₂/P films reveal that the few-layered WS₂ is of high quality, exhibiting continuity and uniformity. The presence of a strong peak in the photoluminescence spectrum confirms the mono/few layer nature of the synthesized samples. In additionally, scanning force microscopy in quantitative imaging mode reveals that the thinnest layers observed on the substrate have a height of 1.35 nm, indicating the presence of double-layer WS₂. The WS₂/P electrocatalyst demonstrates superior HER performance compared to pristine WS₂, showing a low overpotential of 245 mV at 10 mA.cm^-2 and a small Tafel slope of 123 mV.dec^-1. Furthermore, WS₂/P exhibits a greater electrochemical surface area and excellent catalytic stability under acidic conditions. Consequently, few layer phosphorus-doped WS₂ proves to be a highly suitable electrocatalyst for hydrogen production compared to the WS₂.