Enhancement of hydrogen evolution electrocatalytic activity by tungsten carbide nanoparticles confined within 3D mesoporous graphene networks

Tungsten carbide, known for its Pt-like electronic structure, excellent conductivity, and robust chemical stability, is considered a promising noble-metal-free electrode for the hydrogen evolution reaction (HER). However, synthesis of tungsten carbide requires harsh conditions—such as high temperatures and hazardous precursors—and often results in large, aggregated particles with limited catalytic activity. To overcome these limitations, we report a simple and efficient carburization process using 3D mesoporous graphene (MG) as both a carbon source and conductive host material. The resulting tungsten carbide-embedded MG (WCMG) nanohybrids were synthesized at a relatively low temperature of 800 °C and feature uniformly dispersed cubic phase of WC_1-x nanoparticles with an average size of (8.4 ± 3.4) nm, integrated within a highly open porous MG network. These WCMG nanohybrids exhibit a high specific surface area of 563 m² g⁻¹ to 802 m² g⁻¹ and an appropriate pore size of 8.5 nm–8.7 nm, which are expected to enhance the exposure of active sites and accelerate charge transfer kinetics, thereby collectively boosting HER performance. The optimized WCMG catalyst achieves a low overpotential of 179 mV at −10 mA cm⁻² and a Tafel slope of 72 mV dec⁻¹ in acidic media. Furthermore, it demonstrates outstanding stability over 30,000 cycles and 120 h of continuous HER at high current densities (−50 mA cm⁻²). Our results offer great potential in terms of facile designing and producing efficient and durable electrocatalyst materials.