The Tafel plot analysis (Fig. ) provides further insights into the kinetics of the HER for the synthesized tungsten carbide samples. The Tafel slopes of TC-1 to TC-4 fall within a similar range of 53.7, 51.8, 53.7, and 60.5 mV/dec, respectively. These values are significantly larger than the Tafel slope of 29.53 mV/dec observed for the Pt/C, suggesting more sluggish kinetics at low current densities compared to Pt/C. Based on the Tafel plot data, the rate-determining step for the tungsten carbide samples is likely the Heyrovsky reaction (electrochemical desorption of H2) at low current densities . Furthermore, as shown in Fig. , the Tafel slopes of the tungsten carbide samples remain below 120 mV/dec across different current density ranges, indicating rapid kinetic processes even at high current densities. Notably, TC-3 exhibits higher rapid kinetics compared to TC-1, TC-2, and TC-4, which can be attributed to a lower reaction resistance of TC-3 compared to the other samples. Such a lower reaction resistance of TC-3 can be linked to the optimized compositions of WC and W2C phases. It should be noted that the HER kinetics for all the tungsten carbide samples appear faster than that of Pt/C at current densities larger than 100 mA/cm 2 , indicating the superior HER performance of FJH-fabricated tungsten carbide catalysts operating at high current densities.