A facile and rapid FJH method has been successfully employed to synthesize tungsten carbide electrocatalysts with well-controlled phase compositions, demonstrating exceptional acidic HER catalytic activity, particularly at high current densities. The tungsten carbide electrocatalysts were synthesized with varying FJH durations to tailor the phase composition, enabling the coexistence of WC and W2C phases and capitalizing on their potential synergistic effects. Notably, the TC-3 catalyst outperformed other tungsten carbide catalysts, with a low overpotential (387 mV) achieved at a high current density of 4 A/cm 2 . Moreover, the TC-3 catalyst showcases its exceptional stability by maintaining a constant potential during continuous electrolysis for over 150 hours (>6 days), which sets it among the best acidic HER electrocatalysts. This outstanding combination of high efficiency and exceptional stability renders the TC-3 catalyst a promising candidate for industrial-scale hydrogen production applications.