Free-standing N-enriched C foam@WS2 nanoflakes for efficient electrocatalytic hydrogen evolution

Abstract WS 2 , as a promising alternative of noble metal based electrocatalysts, has the advantages of abundant resource and low cost, attracting more and more attention in hydrogen evolution reaction (HER). However, the poor conductivity, and serous stacking and aggregation commonly existed in WS 2 nanostructures have greatly limited its application in practical hydrogen production. Here, novel binder-free and free-standing N-enriched carbon foam@WS 2 nanoflakes (NE-CF@WS 2 NFs) was successfully prepared via a facile, one-step thermal evaporation process, which could directly be used as the working electrode for HER in water splitting, displaying excellent electrocatalytic activity with a low overpotential of 153 mV at the current density of −10 mA cm −2 and a small Tafel slope of 58.7 mV dec −1 , and favorable electrochemical stability and durability. Our study also indicates that the outstanding HER performance of the present catalyst could mainly be attributed to the fast electron transfer at the catalyst/electrolyte interface and the enhanced number of active sites originating from the interconnected 3D porous framework structure with high conductivity. In addition, the present environmentally friendly synthesis strategy might also be employed to prepare other interconnected 3D porous, free-standing and binder-free nanocomposites for various applications, such as Li-ion batteries, Na-ion batteries, supercapacitors and water electrolysis.