In-situ mediation of graphitic carbon film-encapsulated tungsten carbide for enhancing hydrogen evolution performance and stability.

• WC particles were successfully in-situ wrapped with graphitic carbon films (GCFs). • GCFs possessed high degree of graphitization and ultrathin edges. • In-situ growth of GCFs could effectively prevent WC particles from agglomeration. • The WC@GCFs-Pt presented excellent HER performance and long cycling durability. • Enhanced electrochemical performance was ascribed to GCFs combining WC with Pt. Tungsten carbide (WC) particles-embedded carbon nanomaterials with ultrathin edges and high degree of graphitization are very favorable co-catalysts for Pt in electrochemical fields. Herein, WC-embedded graphite carbon films (WC@GCFs) were successfully fabricated as co-catalysts for hydrogen evolution reaction (HER) via an in-situ carbonization technique. The mass specific activity of the WC@GCFs loading Pt NPs is 278 mA mg−1 Pt and 277 mA mg−1 Pt under the overpotential of 48 and 52 mV, which is 1.3 and 1.45 times higher than those of the commercial Pt-C (212.8 mA mg−1 Pt and 191.4 mA mg−1 Pt). The WC@GCFs-Pt displays excellent high stability for HER in acidic and alkaline media even after 5000 potential cycles. As expected, the GCFs originated from the surface of WC can effectively prevent WC particles from agglomeration, which contributes to high catalytic activity and stability of WC. The in-situ formed GCFs possesses ultrathin edges (~5 carbon layers), high degree of graphitization, and some oxygen-containing function groups. Charges are easily transferred from Pt NPs to WC via the linked-GCFs, which contributes to the high HER activity of WC@GCFs-Pt. We believe this work can provide a more economical and efficient route for large-scale synthesis of graphite carbon films coated transition metal carbide as co-catalysts in electrochemical fields. [Display omitted] [ABSTRACT FROM AUTHOR]