scholarly journals Facile synthesis of preformed mixed nano-carbon structure from low rank coal

2018 ◽  
Vol 36 (1) ◽  
pp. 14-20 ◽  
Author(s):  
B. Manoj ◽  
Ashlin M. Raj ◽  
George Thomas Chirayil
Keyword(s):  
Quantum Dots ◽  
Carbon Dots ◽  
Bituminous Coal ◽  
Graphene Quantum Dots ◽  
Energy Resource ◽  
Low Rank ◽  
Tem Analysis ◽  
Graphene Layers ◽  
Simple Chemical ◽  
Nano Carbon

Abstract Coal is a natural energy resource which is mainly used for energy production via combustion. Coal has nanocrystals embedded in it, formed during the coalification process, and is an ideal precursor for nano-carbon dots and diamonds. Herein, we report a facile top-down method to synthesise nanodots and diamonds of the size of 5 nm to 10 nm from three different types of coal by simple chemical leaching. TEM analysis revealed the formation of a mixture of carbon dots, graphene layers, and quantum dots in bituminous coal and sub-bituminous coal. Raman analysis confirmed the existence of synthesized nanodiamond and nano-carbon mixed phase with defects associated with it. It is concluded that graphene quantum dots, nanodiamonds, graphene sheets and carbon dots present in coal can be extracted by simple chemical treatment. These structures can be tuned to photoluminescent material for various optoelectronic applications or energy harvesting devices like super capacitors.

scholarly journals Green Preparation of High Yield Fluorescent Graphene Quantum Dots from Coal-Tar-Pitch by Mild Oxidation

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 844 ◽  
Author(s):  
Quanrun Liu ◽  
Jingjie Zhang ◽  
He He ◽  
Guangxu Huang ◽  
Baolin Xing ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Coal Tar ◽  
Graphene Quantum Dots ◽  
High Yield ◽  
Coal Tar Pitch ◽  
Narrow Size Distribution ◽  
Material Source ◽  
Graphene Layers ◽  
Mild Conditions ◽  
Simple Strategy

Coal tar pitch (CTP), a by-product of coking industry, has a unique molecule structure comprising an aromatic nucleus and several side chains bonding on this graphene-like nucleus, which is very similar to the structure of graphene quantum dots (GQDs). Based on this perception, we develop a facile approach to convert CTP to GQDs only by oxidation with hydrogen peroxide under mild conditions. One to three graphene layers, monodisperse GQDs with a narrow size distribution of 1.7 ± 0.4 nm, are obtained at high yield (more than 80 wt. %) from CTP. The as-produced GQDs are highly soluble and strongly fluorescent in aqueous solution. This simple strategy provides a feasible route towards the commercial synthesis of GQDs for its cheap material source, green reagent, mild condition, and high yield.

Excitation dependence and independence of photoluminescence in carbon dots and graphene quantum dots: insights into the mechanism of emission

Nanoscale ◽  
2021 ◽  
Author(s):  
Abu Bakar Siddique ◽  
Syed Minhaz Hossain ◽  
Ashit Kumar Pramanick ◽  
Mallar Ray
Keyword(s):  
Quantum Dots ◽  
Carbon Dots ◽  
Carbon Nanostructures ◽  
Graphene Quantum Dots ◽  
Emission Characteristics ◽  
Emission Mechanism ◽  
Insight Into

A pattern in excitation dependent and independent emission characteristics provides important insight into the emission mechanism from 0D carbon nanostructures.  

Chemically doped fluorescent carbon and graphene quantum dots for bioimaging, sensor, catalytic and photoelectronic applications

Nanoscale ◽  
2016 ◽  
Vol 8 (5) ◽  
pp. 2532-2543 ◽  
Author(s):  
Yan Du ◽  
Shaojun Guo
Keyword(s):  
Quantum Dots ◽  
Carbon Dots ◽  
Graphene Quantum Dots ◽  
Chemical Doping ◽  
Fluorescent Carbon Dots ◽  
Fluorescent Carbon

Chemical doping for fluorescent carbon dots endows acceptable properties for diverse applications.

Mass production of tunable multicolor graphene quantum dots from an energy resource of coke by a one-step electrochemical exfoliation

Carbon ◽  
2018 ◽  
Vol 140 ◽  
pp. 508-520 ◽  
Author(s):  
Meiqin He ◽  
Xinrong Guo ◽  
Jianzhi Huang ◽  
Huanhuan Shen ◽  
Qiang Zeng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Mass Production ◽  
Graphene Quantum Dots ◽  
Energy Resource ◽  
Electrochemical Exfoliation ◽  
One Step

scholarly journals A Novel Route to High-Quality Graphene Quantum Dots by Hydrogen-Assisted Pyrolysis of Silicon Carbide

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 277 ◽  
Author(s):  
Na Eun Lee ◽  
Sang Yoon Lee ◽  
Hyung San Lim ◽  
Sung Ho Yoo ◽  
Sung Oh Cho
Keyword(s):  
Quantum Dots ◽  
Silicon Carbide ◽  
Quantum Confinement ◽  
Graphene Quantum Dots ◽  
Simple Approach ◽  
Operating Conditions ◽  
High Quality ◽  
Graphene Layers ◽  
High Crystallinity ◽  
Effective Charge Transfer

Graphene quantum dots (GQDs) can be highly beneficial in various fields due to their unique properties, such as having an effective charge transfer and quantum confinement. However, defects on GQDs hinder these properties, and only a few studies have reported fabricating high-quality GQDs with high crystallinity and few impurities. In this study, we present a novel yet simple approach to synthesizing high-quality GQDs that involves annealing silicon carbide (SiC) under low vacuum while introducing hydrogen (H) etching gas; no harmful chemicals are required in the process. The fabricated GQDs are composed of a few graphene layers and possess high crystallinity, few defects and high purity, while being free from oxygen functional groups. The edges of the GQDs are hydrogen-terminated. High-quality GQDs form on the etched SiC when the etching rates of Si and C atoms are monitored. The size of the fabricated GQDs and the surface morphology of SiC can be altered by changing the operating conditions. Collectively, a novel route to high-quality GQDs will be highly applicable in fields involving sensors and detectors.

Ratiometric fluorescence response of a dual light emitting reduced carbon dot/graphene quantum dot nanohybrid towards As(iii)

2019 ◽  
Vol 7 (33) ◽  
pp. 10309-10317 ◽  
Author(s):  
Satyabrat Gogoi ◽  
Rashmita Devi ◽  
Hemant Sankar Dutta ◽  
Manobjyoti Bordoloi ◽  
Raju Khan
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Carbon Dots ◽  
Fluorescence Probe ◽  
Graphene Quantum Dots ◽  
Ratiometric Fluorescence ◽  
Carbon Dot ◽  
Light Emitting ◽  
Graphene Quantum Dot ◽  
Fluorescence Response

A dual light emitting fully carbon-based nanohybrid system comprising of glutathione-functionalized reduced carbon dots and graphene quantum dots is fabricated as ratiometric fluorescence probe for As(iii).

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