Cost-effective　electrocatalysts　for　hydrogen　evolution　reaction　are　attractive　for　energy　conversion　and　storage　processes.　Herein,　a　variety　of　molybdenum-based　catalysts　have　been　synthesized　by　means　of　a　simple　hydrothermal　method　using　cyclodextrin　as　structural　guiding　agent　and　carbon　source.　With　optimizing　the　usage　of　cyclodextrin,　both　molybdenum　oxidate　and　α-type　molybdenum　carbide　can　be　controllable　synthesized　in　terms　of　phase　composition,　morphology　and　porosity.　X-ray　diffraction　patterns　and　high　resolution　transition　electronic　images　show　that　the　as-prepared　sample　appears　a　core-shell　structure　of　MoO2/α-Mo2C　heterojunction.　Surprisingly,　such　heterojunction　as　an　electrocatalyst　exhibits　a　remarkable　hydrogen　evolution　reaction　(HER)　performance　with　low　overpotential　of　100　mV　in　alkaline　electrolyte,　and　of　152　mV　in　acidic　condition　at　a　current　density　10　mA/cm2,　with　very　low　Tafel　slope　of　50　mV/dec　and　65　mV/dec,　respectively.　This　specific　activity　of　presented　material　is　found　to　be　superior　to　those　of　the　most　active　Mo-based　electrocatalysts　reported　so　far.　We　believe　that　our　finding　of　cost-effective　electrocatalysts　for　hydrogen　evolution　reaction　would　open　the　door　for　future　studies　and　applications　of　molybdenum　compounds.　©　2017　Elsevier　B.V.