Photodegradation of water pollutants by g-C۳N۴ nanosheets/nitrogen-dopedcarbon quantum dot nanocomposite

Environmental pollution, especially water pollution, is the inevitable result of the constant expansion ofindustrialization and urbanization. So, it is crucial to develop an environmentally friendly method for waterremediation. In recent years, photocatalysis has attracted considerable attention due to its severaladvantages. The use of sunlight, ease of operation, low cost, and complete degradation of pollutants are justa few of the benefits of this method. In the photocatalysis field, the development of efficient semiconductorsis of great importance. In this study, g-C۳N۴ nanosheets and g-C۳N۴/۰.۱ wt.% nitrogen-doped carbonquantum dots (N-CQD) were synthesized to address the as-mentioned importance. X-ray diffraction (XRD),field emission electron microscopy (FESEM) and transmission electron microscopy (TEM), diffusereflectance spectroscopy (DRS), and photoluminescence (PL) were employed to characterize the samples.Methylene blue (MB) was used to evaluate the photocatalytic performance of the samples. XRD results of thesamples confirmed the successful synthesis. FESEM image of the g-C۳N۴ nanosheets exhibited a ۲-dimensional structure of these nanosheets. N-CQDs introduction with less than ۱۰ nm dimension wasconfirmed by the TEM image. N-CQD introduction significantly impacted the optical properties of the g-C۳N۴nanosheets. An approximate redshift of ۵۰ nm in the absorption edge and ۰.۱۷ eV reduction in the band gapenergy were the results of the N-CQD introduction, which led to an increase in visible light harvesting. PLspectra of the g-C۳N۴/N-CQD nanocomposite exhibited significant intensity reduction, suggestingrecombination prevention of the carriers. Finally, g-C۳N۴/N-CQD nanocomposite showed ۹۹% efficiency inMB photodegradation with a rate constant of ۰.۰۱۸۱ min-۱, which was ۱۲ times higher than the rate constantof the g-C۳N۴ nanosheets.

کلیدواژه ها:

g-C۳N۴ nanosheets ، Nitrogen-doped carbon quantum dot ، Optical properties ، Photocatalyst.