Electrocatalytic water splitting has been one of the most promising routes for efficient H 2 production, which can work as a practical way to store the excess electricity generated by solar panel, wind, and nuclear reactor. Although platinum group Transition metal carbide compound has been extensively investigated as a catalyst for hydrogenation, for example, due to its noble metal-like properties. Herein a facile synthetic strategy is applied to control the thickness of atomiclayer Pt clusters strongly anchored on N-doped Mo 2 C nanorods (Pt/N-Mo 2 C) and it is found that the Pt atomic layers modify Mo 2 C function as a high-performance and robust catalyst for hydrogen evolution. The optimized 1.08 wt% Pt/N-Mo 2 C exhibits 25-fold, 10-fold, and 15-fold better mass activity than the benchmark 20 wt% Pt/C in neutral, acidic, and alkaline media, respectively. This catalyst also represents an extremely low overpotential of −8.3 mV at current density of 10 mA cm −2 , much better than the majority of reported electrocatalysts and even the commercial reference catalyst (20 wt%) Pt/C. Furthermore, it exhibits an outstanding long-term operational durability of 120 h. Theoretical calculation predicts that the ultrathin layer of Pt clusters on Mo-Mo 2 C yields the lowest absolute value of ΔG H* . Experimental results demonstrate that the atomic layer of Pt clusters anchored on Mo 2 C substrate greatly enhances electron and mass transportation efficiency and structural stability. These findings could provide the foundation for developing highly effective and scalable hydrogen evolution catalysts.