To further improve the hydrogen-based energy system, there is an urgent need to replace precious metal-based hydrogen evolution reaction catalysts, including Pt-based materials, with nonprecious metal catalysts for electrochemical production of hydrogen from water. In this work, we propose a novel titanium-doped molybdenum phosphide (Ti-MoP) catalyst. Ti-MoP exhibits a low overpotential of 81.5 mV at 10 mA.cm(-2). In particular, the remarkable improvement in material stability and electrochemical durability allows the catalyst to maintain its initial activity after prolonged exposure to air and shows accelerated electrochemical durability testing under acidic conditions. The experimental results and theoretical calculations revealed that the high durability is the result of electronically reduced Mo and P caused by Ti, and the high activity is a result of the optimization of the free energy of hydrogen adsorption (Delta G(H)) of the abnormally high-valence Ti.