High-efficient electrocatalyst of MoNi4@MoO3-x nanorod for hydrogen evolution reaction in alkaline solutions

•A composite with MoNi4 alloys embedding into MoO3-x porous nanorods was synthesized via a simple in-situ reduction method.•The obtained MoNi4@MoO3-x exhibits a remarkable HER activity with 10 mA/cm2 constant current under 58.6 mV low overpotential.•The remarkable HER activity is found to originate from the MoNi4 alloys, excellent conductivity and porous structure.