Highly Efficient Sulfur and Nitrogen Codoped Graphene Quantum Dots as a Metal-Free Green Photocatalyst for Photocatalysis and Fluorescent Ink Applications

Abstract

The demand for modern organic pollutant treatment has prompted the development of environmentally acceptable photocatalytic processes. In this work, we report novel nitrogen and sulfur codoped graphene quantum dot (S,N-GQD) based photocatalysts and fluorescent ink for the first time. For the degradation of organic dyes under visible irradiation, a hydrothermal technique was employed to generate S,N-GQD green nanomaterials. The synthesized samples were examined using XRD, HR-TEM, EDX, FT-IR, PL, and UV–vis spectroscopy. UV-DRS was used to determine the energy band gap of S,N-GQDs, and it was obtained to be around ∼2.54 eV. To explore the catalytic behavior of the produced S,N-GQDs as green nanomaterials, organic dyes (i.e., crystal violet and Alizarin yellow) have been used as a reference dye in this study. Using several radical scavenging agents, the photocatalytic mechanism was examined. This novel photocatalyst offers a promising alternative for the breakdown of organic pollutants. Moreover, these S,N-GQDs can also be used as fluorescent ink for imaging purposes and security reasons.

Preparation and characterization of carbon quantum dot‐hydroxyapatite‐alginate based hybrid fluorescent ink for sensor application

“…This electron recombination effects in fluorescence quenching with respect to the concentration of the analyte molecules. These results pointedly evident that the presence of hydroxyl groups on the surface of the CQD is one of the key factor for sensitive and selective detection of organic molecules 31,32 …”

“…These results pointedly evident that the presence of hydroxyl groups on the surface of the CQD is one of the key factor for sensitive and selective detection of organic molecules. 31,32…”

Advances in the ratiometric combination of quantum dots for their use in sensing applications

“…[33][34][35] Under analysis by XRD, CQDs give rise to a broad peak between the 2y value of 21-261, which is due to the (002) plane. 36 The fluorescence and absorbance spectra of CQDs have comparable optical behavior when it comes to their optical features. Following UV stimulation, they often exhibit robust emission in the visible spectrum, including high UV absorption and an extended visible spectrum tail.…”

Colloidal Quantum Dots: Synthesis, Composition, Structure, and Emerging Optoelectronic Applications

“…The DE could reach 93% within 30 min under visible light irradiation. Recently, Selvakumar et al [342] measured 500 μL of nitrogen and sulfur codoped carbon quantum dots (S,N-CDs) to degrade 50 mL of crystal violet and Alizarin yellow (20 ppm). After irradiation 100 min, the corresponding DE were 91% and 64% under a 400 W xenon lamp, respectively.…”