The fabrication of efficient and stable catalysts to accelerate the kinetics of the hydrogen evolution reaction (HER) is a crucial step in the development of sustainable energy production. The structural design of Pt-based catalysts with efficient atom utilization remains a pivotal factor in the continued advancement of HER catalysts. In this work, we synthesized phosphorylated Mo-based particles embedded in P-doped carbon materials for the optimized loading of platinum nanoparticles (Pt/Mo-P@C). Theoretical results indicate that the catalytic efficacy of the materials can be enhanced by altering the electronic structure of Pt nanoparticles through the precise formation of Pt–Mo bond and multiple heterostructures. The catalysts exhibited exceptional mass activity after low-temperature reduction, achieving a current density of 100 mA·cm⁻² at 54.4 mV, which is lower than that of the commercial Pt/C catalyst. Furthermore, the mass activity of the main catalyst was 6.7 times greater than that of the commercial Pt/C catalyst at an overpotential of 50 mV.