Electrochemical water splitting has been highly valued as a clean and sustainable method to produce hydrogen with high purity and large quantity. Platinum (Pt) possesses excellent performance for hydrogen evolution reaction (HER), however, the expensiveness and rareness still restricts its broad application. Here, an environmentally-friendly and template-free method is developed to synthesize N-doped molybdenum carbide in three different forms: nanobelts, nanorods and nanoparticles. During the synthesis, no additional acid or alkali aqueous solution is used and the morphology is controlled by adjusting water content and treatment time. The corresponding physicohemical and electrochemical results display that the nanobelts with porous nanostructure exhibit excellent activity and good stability for HER both in acidic and alkaline electrolytes. In the latter case (1.0 M KOH aqueous solution), nanobelts show a small onset potential value (-52 mV), yield a current density of 10 mA cm(-2) at a relatively low overpotential (110 mV) and exhibit a low Tafel slope (49.7 mV dec(-1)). From the obtained results is deduced that this is a facile way to prepare cost-effective molybdenum carbide with high efficiency for hydrogen evolution.