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

[Display omitted] • Design and manufacture of Ni/MoO 2 catalysts with different morphologies, which confirm the effect of morphology engineering. • The excellent catalytic performance of H-Ni/MoO 2 benefits from a hollow porous spherical structure with amorphous carbon skeleton, compared with other morphological Ni/MoO 2. • 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. The catalyst morphology has a strong impact on the activity of electrocatalytic hydrogen production. Considering the effect, we design and fabricate hollow spherical Ni/MoO 2 heterojunction. In addition, an amorphous carbon skeleton is inserted into the hollow sphere, which makes the structure more stable and porous. Compared with other morphological Ni/MoO 2 , the porous hollow spherical Ni/MoO 2 (H-Ni/MoO 2) with an internal carbon skeleton shows better hydrogen evolution reaction (HER) activity with a small overpotential of 58 mV to reach 10 mA cm−2 and a tafel value of 44.8 mV dec-1 in alkaline media. The developed HER performance of H-Ni/MoO 2 can be attributed to the larger active surface area of porous hollow spherical structure and the faster electron transfer and better stability of carbon skeleton. Undoubtedly, the urea plays a crucial role to construct the hollow spherical morphology and being decomposed to form holes and amorphous carbon in the synthesized steps. The soft-template strategy using urea as the addition for forming the porous hollow structure with carbon skeleton can be extended to explore superior non-noble metal for hydrogen production. [ABSTRACT FROM AUTHOR]