Gram-scale synthesis of high-purity graphene quantum dots with multicolor photoluminescence

RSC Advances ◽  
2015 ◽  
Vol 5 (125) ◽  
pp. 103428-103432 ◽  
Author(s):  
Fuchi Liu ◽  
Yuanyuan Sun ◽  
Yongping Zheng ◽  
Nujiang Tang ◽  
Ming Li ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Nitric Acid ◽  
Carbon Black ◽  
High Purity ◽  
Graphene Quantum Dots ◽  
Experimental System ◽  
System P

A gram-scale approach has been developed to prepare highly pure graphene quantum dots (GQDs) from Vulcan XC-72 carbon black refluxed with concentrated nitric acid using a home-built experimental system.

A reformative oxidation strategy using high concentration nitric acid for enhancing the emission performance of graphene quantum dots

RSC Advances ◽  
2014 ◽  
Vol 4 (89) ◽  
pp. 47977-47981 ◽  
Author(s):  
Taili Shao ◽  
Guodong Wang ◽  
Xuting An ◽  
Shujuan Zhuo ◽  
Yunsheng Xia ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Nitric Acid ◽  
Quantum Yield ◽  
Graphene Quantum Dots ◽  
High Concentration ◽  
Emission Performance

Red fluorescent graphene quantum dots with 18% quantum yield at 600 nm were obtained through a concentrated HNO3oxidation strategy.

scholarly journals Transforming Carbon Black into Graphene Oxide Quantum Dots by Pulsed Laser Ablation in Ethanol

2020 ◽  
Vol 58 (11) ◽  
pp. 808-814
Author(s):  
Jung-Il Lee ◽  
Jeong Ho Ryu
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Laser Ablation ◽  
Carbon Black ◽  
Graphene Quantum Dots ◽  
Pulsed Laser ◽  
Blue Emission ◽  
Pulsed Laser Ablation ◽  
Absorption Bands ◽  
Graphene Oxide Quantum Dots

Graphene oxide quantum dots (GOQDs) are nanometer-sized graphene oxide fragments that exhibit unique properties, making them interesting candidates for a range of new applications. Carbon black, one of the commercially available carbon precursors, is produced by the thermal decomposition or incomplete combustion of organic compounds. It is commonly used as a supporting material for catalysts because of its excellent electrical conductivity, high surface area, and stability. In this paper, we report the transformation of carbon black into GOQDs in 10 min using a one-step facile approach. This transformation was achieved by pulsed laser ablation (PLA) in ethanol using the earth-abundant and low-cost carbon black as precursor. Only ethanol and carbon black were used for the transformation. The carbon clusters ablated from the carbon black were completely transformed into GOQDs with a homogeneous size distribution and heights in the range of 0.3-1.7 nm. This confirmed that the transformed GOQDs consisted of only single- or few-layered graphene quantum dots. The UV-vis spectra showed absorption bands at 215, 260, and 320 nm, which were attributed to the π→π* transition of the C=C of the sp<sup>2</sup> C bond in the sp<sup>3</sup> C matrix. A distinct blue emission peak at 450 nm was evident at an excitation wavelength of 360 nm. The broader PL emission spectra are due to the oxygen-related functional groups emitting PL between 300 and 440 nm.

High-Purity Amino-Functionalized Graphene Quantum Dots Derived from Graphene Hydrogel

NANO ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. 1650138 ◽  
Author(s):  
Yinhua Jin ◽  
Hongyi Qin ◽  
Jang Ah Kim ◽  
Sun-Young Kim ◽  
Hyeong-U Kim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Purity ◽  
Hydrothermal Reaction ◽  
Graphene Quantum Dots ◽  
Synthesis Method ◽  
Water Soluble ◽  
Synthesis Process ◽  
Functionalized Graphene ◽  
Ultrasonic Probe ◽  
Low Cytotoxicity

The unique properties of graphene quantum dots (GQDs) make them interesting candidate materials for innovative applications. Herein, we report a facile method to synthesize amino-functionalized graphene quantum dots (AF-GQDs) by a hydrothermal reaction. Graphene oxide (GO) was synthesized by Hummer’s method where ultra-small GO sheets were obtained by a prolonged oxidation process followed by sonication using an ultrasonic probe. Subsequently, graphene hydrogel (GH) was also obtained by a hydrothermal synthesis method. Proper care was taken during synthesis to avoid contamination from water soluble impurities, which are present in the precursor, GO solution. Following the treatment of GH in ammonia, ultra-small amino-functionalized graphene fragments (AF-GQDs) were formed, which detached from the GH to eventually disperse evenly in the water without agglomerating. This modified synthesis process enables the formation of high-purity AF-GQDs (99.14%) while avoiding time-consuming synthesis procedures. Our finding shows that AF-GQDs with sizes less than 5[Formula: see text]nm were well dispersed. A strong photoluminescence (PL) emission at [Formula: see text]410[Formula: see text]nm with 10% PL quantum yield was also observed. These AF-GQDs can be used in many bio applications in view of their low cytotoxicity and strong fluorescence that can be applied to cell imaging.

One-step and high yield simultaneous preparation of single- and multi-layer graphene quantum dots from CX-72 carbon black

2012 ◽  
Vol 22 (18) ◽  
pp. 8764 ◽  
Author(s):  
Yongqiang Dong ◽  
Congqiang Chen ◽  
Xinting Zheng ◽  
Lili Gao ◽  
Zhiming Cui ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Black ◽  
Graphene Quantum Dots ◽  
High Yield ◽  
Layer Graphene ◽  
One Step

Comparing the corrosion protection performance of graphene nanosheets and graphene quantum dots as nanofiller in epoxy coatings

2019 ◽  
Vol 71 (5) ◽  
pp. 653-656 ◽  
Author(s):  
Sepideh Pourhashem ◽  
Alimorad Rashidi ◽  
Mohammad Reza Vaezi
Keyword(s):  
Quantum Dots ◽  
Corrosion Resistance ◽  
Carbon Black ◽  
Corrosion Protection ◽  
Graphene Nanosheets ◽  
Graphene Quantum Dots ◽  
Polymer Matrice ◽  
Chemical Vapor Deposition Method ◽  
Epoxy Coatings ◽  
Content Type

Purpose In this research, the effect of graphene nanosheets and graphene quantum dots (GQDs) as carbon-based nanofillers on corrosion protection performance of epoxy coatings is considered. Design/methodology/approach Graphene nanosheets are synthesized via chemical vapor deposition method, and GQDs are synthesized by a simple and gram scale procedure from carbon black. The prepared nanofillers are characterized by X-ray diffraction technique, Fourier transform infrared spectroscopy and transmission electron microscopy. Further, solvent-based epoxy coatings containing 0.1 Wt.% graphene nanosheets and GQDs are prepared, and the corrosion resistance of nanocomposite coatings is considered by electrochemical impedance spectroscopy. Findings The results indicate that both epoxy/graphene nanosheets and epoxy/GQDs samples have significantly higher corrosion resistance than pure epoxy coating. Meanwhile, GQDs can more effectively enhance the corrosion protection performance of epoxy coatings compared to graphene sheets, which can be attributed to the presence of functional groups on GQDs and improving the dispersion quality in polymer matrice. Originality/value In this research, for the first time, the graphene quantum dots (GQDs) prepared by a “top-down” method from carbon black are used as nanofiller in epoxy coatings, and the potential application of graphene nanosheets and GQDs as anti-corrosion nanofiller in epoxy coatings is investigated.

Graphene quantum dots enhanced photocatalytic activity of zinc porphyrin toward the degradation of methylene blue under visible-light irradiation

2015 ◽  
Vol 3 (16) ◽  
pp. 8552-8558 ◽  
Author(s):  
Qian Lu ◽  
Yuanjian Zhang ◽  
Songqin Liu
Keyword(s):  
Methylene Blue ◽  
Quantum Dots ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Graphene Quantum Dots ◽  
Light Irradiation ◽  
Zinc Porphyrin ◽  
System P ◽  
Excellent Photocatalytic Activity

Microstructures of GQDs–ZnPor displayed excellent photocatalytic activity toward degradation of MB in a visible-light system.

scholarly journals Direct Synthesis of Graphene Quantum Dots with Different Fluorescence Properties by Oxidation of Graphene Oxide Using Nitric Acid

2018 ◽  
Vol 8 (8) ◽  
pp. 1303 ◽  
Author(s):  
Meilian Zhao
Keyword(s):  
Quantum Dots ◽  
Graphene Oxide ◽  
Nitric Acid ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Direct Synthesis ◽  
Critical Role ◽  
Graphene Quantum Dots ◽  
Optical Fields ◽  
Electron Microscopic

Graphene quantum dots (GQDs) play a critical role in many applications in the electrical and optical fields. We develop a simple three-step hydrothermal etching method to prepare GQDs by adopting graphene oxide (GO) as a precursor and nitric acid as an oxidant. We discuss the formation mechanism of GQDs by the characterization of products and intermediates with Scanning electronic microscopy (SEM), Transmission electron microscopic (TEM), Raman, Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Two kinds of GQDs have been obtained after the treatment of GO with different concentrations of nitric acid. The sizes of GQDs are small, with diameters of 3.38 nm and 2.03 nm on average, respectively. When excited with 365 nm UV light, the two kinds of GQDs exhibit green and yellow luminescence; the different optical properties can be attributed to the differences in degree of oxidation and nitrogen doping. The result is important for GQDs in synthesizing and optical field.

Sign in / Sign up

Export Citation Format

Share Document