Ultrafine WC nanoparticles anchored on co-encased, N-doped carbon nanotubes for efficient hydrogen evolution

Abstract

The high-activity electrocatalysts for the hydrogen evolution reaction (HER) are highly desired to replace precious Pt, but difficult to achieve. Herein, we report the loading of ultrafine tungsten carbide (WC) nanoparticles (NPs) on cobalt-embedded, bamboo-like, nitrogen-doped carbon nanotubes (WC/Co@NCNTs) with high-level N doping via a one-step strategy, leading to a desirable multicomponent nanocomposite with superior activity and stability when used as the HER electrocatalyst. The optimized WC/Co@NCNTs showed a very low onset overpotential (Uonset) of ~18 mV, a small Tafel slope of 52 mV dec−1, a small η10 of only 98 mV to reach a current of 10mAcm−2, and a large exchange current density (j0) of 0.103mAcm−2, which also retained its high activity for at least 12.5h operation in acidic electrolyte. The DFT calculations revealed an important role of the N dopants in the HER as well as a favorable ΔGH* for the adsorption and desorption of hydrogen derived from the synergistic effects between WC NPs and Co@NCNTs.