Imaging Science and Photochemistry ›› 2015, Vol. 33 ›› Issue (5): 417-425.DOI: 10.7517/j.issn.1674-0475.2015.05.417

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Graphitic Carbon Nitride Nanotubes: Synthesis and Photocatalytic Activity for Hydrogen Evolution

ZHENG Yun, WANG Bo, WANG Xinchen   

  1. State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou 350002, Fujian, P. R. China
  • Received:2015-07-01 Revised:2015-07-12 Online:2015-09-16 Published:2015-09-16


Graphitic carbon nitride nanotubes (CN-NTs) photocatalyst has been synthesized by a hard-template method by using cyanamide as a precursor and silica nanotubes (SiO2-NTs) as a hard template. The structure and properties of CN-NTs catalyst are characterized by the techniques of scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), nitrogen absorption/desorption experiment, ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS), fluorescence spectra and thermogravimetric analysis (TGA). As demonstrated by the experimental results, CN-NTs possess the chemical structure of graphitic carbon nitride (g-C3N4) and the morphology of uniform nanotubes, and belong to mesoporous materials. Compared with the bulk carbon nitride (B-CN) and the mesoporous graphitic carbon nitride (mpg-CN), the optical absorption band edge of CN-NTs blue-shifts to 440 nm, and the peak intensity of the fluorescence emission spectra for CN-NTs reduces. With the visible light irradiation (λ>420 nm), CN-NTs show an outstanding photocatalytic water splitting activity with the hydrogen evolution rate of 58 μmol/h, and also demonstrate excellent stability in photocatalytic activity and chemical structure. The investigation results indicate that the nanotube structure effectively promotes the exciton separation of g-C3N4 semiconductor, and improves the separation efficiency of photogenerated electrons and holes, thus remarkably optimizing the photocatalytic activity of g-C3N4 toward hydrogen evolution.

Key words: graphitic carbon nitride, nanotube, hard template, photocatalysis, hydrogen energy