MoS 2 /RGO nanocomposites as highly effective electrocatalysts for hydrogen evolution reaction (HER) have been synthesized by one-pot solvothermal route using dimethyl-formamide (DMF) as solvent. For comparison, MoS 2 /RGO has also been prepared in pure H 2 O and H 2 O–DMF mixture. The good dispersion of MoS 2 nanoparticles on the surface of MoS 2 /RGO obtained in DMF can be seen from TEM and SEM images, which implying the more active sites for HER. The electrocatalytic measurements confirm that the obtained MoS 2 /RGO in DMF exhibits the smaller onset overpotential of 130 mV and lower tafel slop of 42 mV dec À 1 , which indicating the better electrocatalytic activity than MoS 2 /RGO in H 2 O or H 2 O–DMF mixture. It may be attributed to the better role of DMF on dispersing RGO and controlling the growth of MoS 2. Therefore, DMF may be the more suitable solvent for preparing excellent electrocatalysts for HER than H 2 O.