Photoreactive carbon dots modified g-C3N4 for effective photooxidation of bisphenol-A under visible light irradiation

Iqbal, Anwar and Shittu, Fatimah Bukola and Mohamad Ibrahim, Mohamad Nasir and Abu Bakar, N. H. H. and Yahaya, Noorfatimah and Rajappan, Kalaivizhi and Hussin, Mohd. Hazwan and Danial, Wan Hazman and Wilson, Lee D. (2022) Photoreactive carbon dots modified g-C3N4 for effective photooxidation of bisphenol-A under visible light irradiation. Catalysts, 12. ISSN 2073-4344

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Abstract

A series of carbon dots (CDs) modified g-C3N4 (xCDs/g-C3N4; x = 0.5, 1.0, and 1.5 mL CDs solution) was synthesized via the microwave-assisted hydrothermal synthesis method for the photooxidation of bisphenol-A (BPA) under visible light irradiation. The X-ray diffraction (XRD) analysis indicates that the CDs may have a turbostratic structure and the resulting photocatalysts have distorted crystal structure, as compared with pure g-C3N4. The high-resolution transmission electron microscope (HR-TEM) analysis revealed amorphous, mono-disperse, spherical CDs with an average particle size of 3.75 nm. The distribution of CDs within the matrix of g-C3N4 appear as small dark dot-like domains. The N2 adsorption-desorption analysis indicates that the nanocomposites are mesoporous with a density functional theory (DFT) estimate of the pore size distribution between 2–13 nm. The CDs quantum yield (QY) was determined to be 12% using the UV-vis spectral analysis, where the CDs/g-C3N4 has improved absorption in the visible region than g-C3N4. The higher BET surface area of CDs/g-C3N4 provided more adsorption sites and the ability to yield photogenerated e−/h+ pairs, which caused the 1.5 CDs/g-C3N4 to have better photocatalytic efficiency compared to the rest of the systems. The highest removal, 90%, was achieved at the following optimum conditions: BPA initial concentration = 20 mg L−1, catalyst dosage = 30 mg L−1, and pH = 10. The photooxidation process is mainly driven by photogenerated holes (h+) followed by •OH and O2•−. The synthesis of the 1.5 CDs/g-C3N4 system is simple and cost-effective, where this photocatalyst is highly stable and reusable versus other systems reported in the literature.

Item Type:	Article (Journal)
Uncontrolled Keywords:	bisphenol-A; carbon quantum dots; g-C3N4; photocatalysis; visible light irradiation
Subjects:	Q Science > QD Chemistry
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Science Kulliyyah of Science > Department of Chemistry
Depositing User:	Dr Wan Hazman Danial
Date Deposited:	02 Dec 2022 11:09
Last Modified:	02 Dec 2022 11:21
URI:	http://irep.iium.edu.my/id/eprint/101534

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