Investigation on the Growth Mechanism of Cu2MoS4 Nanotube,Nanoplate and its use as a Catalyst for Hydrogen Evolution in Water

Cu₂MoS₄ is a ternary transition‐metal sulfide that shows great potential in the field of energy conversion and storage, namely catalytic H₂ evolution in water and Li‐, Na‐ or Mg‐ion battery. In this work, we report on a growth mechanism of the single‐crystalline Cu₂MoS₄ nanotube from (NH₄)₂MoS₄ salt and Cu₂O nanoparticle. By probing the nature and morphology of solid products generated in function of reaction conditions we find that the crystalline Cu(NH₄)MoS₄ nanorod is first generated at ambient conditions. The nanorod is then converted into Cu₂MoS₄ nanotube under hydrothermal treatment due to the Kirkendall effect or a selective etching of the Cu₂MoS₄ core. Extending the hydrothermal treatment causes a collapse of nanotube generating Cu₂MoS₄ nanoplate. The catalytic activities of these sulfides are investigated. The Cu₂MoS₄ shows superior catalytic activity to that of Cu(NH₄)MoS₄. Catalytic performance of the former largely depends on its morphology. The nanoplate shows superior catalytic activity to the nanotube, thanks to its higher specific electrochemical surface area.