Fullerene-like WS2 supported Pd catalyst for hydrogen evolution reaction

Hydrogen is the most desirable green energy carrier and electrocatalytic hydrogen evolution reaction (HER) from water is a promising route for hydrogen production. The search for efficient, low-cost HER catalysts is a challenging and attracting topic. In this work, we report that inorganic fullerene-like WS2 supported Pd nanoparticles (Pd/WS2), with Pd loading of 0.76 wt%, are active for electrocatalytic HER conducted in 0.5 M H2SO4 solution, with overpotential at 10 mA cm−2 current density of ~130 mV and Tafel slope of 82.4 mV dec−1, which is comparable to that of Pt/WS2 (0.88 wt% Pt loading) with higher costs. Characteristic results indicate that WO3 impurities were in-situ produced on the WS2 surface and the Pd NPs are primarily located inside the WS2 nanocages. Contrasting experiments suggest that the WO3 impurities play a crucial role in generating Hads intermediate and the Pd NPs are active sites of H2 production, and a reaction mechanism is proposed. The Pd/WS2 catalyst also shows good long-term stability owing to the location of Pd NPs inside the WS2 cages. The high HER activity, low costs and good stability make the Pd catalyst a potential alternative to Pt catalyst for HER.