Insertion of carbon skeleton in Ni/MoO2 heterojunction with porous hollow sphere for efficient alkaline electrochemical hydrogen production

•Design and manufacture of Ni/MoO2 catalysts with different morphologies, which confirm the effect of morphology engineering.•The excellent catalytic performance of H-Ni/MoO2 benefits from a hollow porous spherical structure with amorphous carbon skeleton, compared with other morphological Ni/MoO2.•The urea plays crucial role in porous hollow spherical morphology and carbon skeleton in the synthesized steps.•The urea-assistant synthesized way offers a simple and practical strategy to construct this structure for catalysts.