Open AccessThe effect of excitation light source and humidity to photocatalytic activity of g-C3N4 nanosheets for NO removal
Author(s) -
Vinh Hoang The Tran,
Tu Cam Huynh,
Viet Van Pham
Publication year - 2021
Publication title -
khoa học công nghệ
Language(s) - English
Resource type - Journals
ISSN - 1859-0128
DOI - 10.32508/stdj.v24i2.2521
Subject(s) - photocatalysis , materials science , annealing (glass) , semiconductor , chemical engineering , melamine , nanometre , exfoliation joint , fourier transform infrared spectroscopy , nanotechnology , composite material , optoelectronics , catalysis , organic chemistry , chemistry , graphene , engineering
Photocatalysis using nanostructured semiconductors is the potential strategy to solve the problem of environmental pollution. Besides traditional semiconductor materials, the novel polymeric metal-free semiconductor g-C3N4 has emerged as a potential substitute material because of its many outstanding features.
Methods: This study successfully synthesized two dimensions (2D)-structured g-C3N4 nanosheets by a simple thermal-exfoliation method with annealing route at 2 oC/min. Firstly, melamine was placed in a ceramic crucible with cover and then undergone the annealing route at 550 oC for 2 h to develop into the g-C3N4 bulk. Then the assynthesized g-C3N4 bulk was further annealed without the cover at 550 oC for 2 h to form the final product, g-C3N4 nanosheets.
Results: The results of XRD patterns and FTIR spectra show two typical diffractions peaks and chemical bonds that characterize the g-C3N4 matrix. The TEM images demonstrated that the as-prepared g-C3N4 possesses 2D-structured material, including several singly exfoliated sheets with a width of around several hundred nanometers. The photocatalytic NO removal efficiency of g-C3N4 nanosheets is highest at 48.27% under 30 min solar irradiation at 70% humidity. Meanwhile, the NO2 conversion yield is very low, only 9.44%, much smaller than the NO decomposition efficiency to form NO3 ion products. The results of trapping tests indicated that the hole plays the most critical role in the photocatalytic process of g-C3N4 nanosheets. Especially, the photocatalytic NO removal efficiency still achieves 45.03% after the recycling test. Moreover, all characteristic peaks and chemical bonds in material remain even undergoing fifth times reuse as the results of XRD and FTIR.
Conclusion: From various modern analytic characterization methods and photocatalytic investigation, we can concluse that g-C3N4 nanosheets are very stable and possible to apply in practical applications to decompose NO gas at atmospheric conditions.