Cobalt-Encapsulated in Nitrogen-Doped Carbon Nanotubes Prepared by Hydrothermal Method as Catalyst for Hydrogen Evolution

Abstract

Cobalt-encapsulated in nitrogen-doped carbon nanotubes (Co-NCNT) were prepared by hydrothermal method. CoCl₂·6H₂O and graphitic carbon nitride (g-C₃N₄) were used as raw material. Samples containing such defective structures were synthesized by hydrothermal methods, while there is an excellent synergistic effect between cobalt nanoparticles and carbon nanotubes on hydrogen evolution reaction (HER). In order to improving the HER performance, different samples were fabricated by changing the molar ratio of raw materials and pyrolysis temperature. The results show that Co-NCNT has the best HER performances at the ratio of CoCl₂·6H₂O and g-C₃N₄ (1:7) when the pyrolysis temperature reached 700 °C. The overpotential has reached 285 mV when the current density is 10 mA·cm⁻², the Tafel slope of the sample is 103 mV·dec⁻¹.

Keywords:

• Hydrothermal method
• carbon nanotubes
• nitrogen-doped
• hydrogen evolution reaction