Photocatalytic performance of carbon nitride nanosheets synthesized by a bottom-up approach

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: 1020-UFGNSM2021-FULL (R2)
1School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran
2University of Tehran
Graphitic carbon nitride has gotten more attention in the photocatalysis field over the past decade due to its electronic and structural properties. Photocatalytic activity of bulk g-C3N4 can be improved by producing g-C3N4 nanosheets. Herein, g-C3N4 nanosheets were synthesized through one-step polymerization using ammonium chloride (NH4Cl) as a blowing agent to overcome Van der Waals forces between layers in the graphitic structure. The prepared photocatalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM) and diffuse reflectance spectroscopy (DRS). Methylene blue (MB) was used to investigate the photocatalytic activity of the samples under visible light radiation. XRD results showed two main peaks of bulk and nanosheets and the calculated crystallite size of g-C3N4 nanosheets was about 4 nm. FESEM images showed that g-C3N4 nanosheets were successfully synthesized and the 2D morphology of the nanosheets in comparison with bulk g-C3N4 had a higher specific surface area. Irregular bulk g-C3N4 particles were 3 μm in size. Whereas, the thickness of the g-C3N4 nanosheets was approximately 5nm. Optical properties of bulk g-C3N4 and nanosheets were also investigated by the DRS test and g-C3N4 nanosheets showed a slight blue shift compared to the bulk g-C3N4. The calculated band gaps for bulk and nanosheets were 2.80 and 2.85, respectively. Both adsorption capacity and photodegradation efficiency of g-C3N4 nanosheets were improved and showed 42% efficiency by introducing a certain amount of NH4Cl as a blowing agent rather than bulk g-C3N4 which showed only 6% degradation after 180 min visible light radiation.
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