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

Abstract

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.