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The Impact of Carbon-Based Nanomaterials in Biological Systems
Published in Swamini Chopra, Kavita Pande, Vincent Shantha Kumar, Jitendra A. Sharma, Novel Applications of Carbon Based Nano-Materials, 2023
Leirika Ngangom, Kunal Sharma, Pankaj Bhatt, Nilay Singhand, Neha Pandey
Carbon is the sole and imperative element on the Earth and is ranked as the second component that is present in a human body comprising about 18% of the individual’s weight. The remarkable character of the carbon element is that its wide range of metastable stages can be arranged or formed around the intermediate surroundings. In addition to this, the function of carbon is vital as it forms a bond with the enclosing light components and also with itself despite the scarce amount available around the Earth’s crust, which is about 0.032% from the overall mass of the planet (Zhang et al. 2012, Marty et al. 2013). Therefore, the functional capability of carbon elements has bought a wide expansion in the field of biology and chemistry. In the current era, the study of carbon science is very contemporary, and in some research areas, such as engineering and technology, materials science, nanoscience, and carbon nanostructures, have carbon elements of various low dimensions comprising carbon nanotubes, graphene, and activated carbon (Geim et al. 2007, Titirici et al. 2015, Deng et al. 2016). There are different allotropic forms of carbon, namely graphite, buckminsterfullerene (smallest fullerene molecule), and diamond. Among the allotropes of carbon mentioned, the thermodynamically stable allotrope is graphite. It has a high thermal and electrical conductivity that makes it suited for use in various applications that demands high temperatures. Graphite is a crystalline form of carbon molecule and its atoms configured in a hexagonal
Synthesis of Graphene from Vegetable Waste
Published in Amir Al-Ahmed, Inamuddin, Graphene from Natural Sources, 2023
R. Imran Jafri, Adona Vallattu Soman, Athul Satya, Sourav Melethethil Surendran, Akshaya S. Nair
Carbon is a unique and omnipresent material present in nature. It is a non-metallic tetravalent element capable of forming complicated networks, which is the basis of existence of life. Carbon and its allotropes in zero-dimension (fullerene), one-dimension (nanotubes), two-dimensional (graphene), and three-dimension (diamond and graphite) exhibit different chemical, physical, and electronic properties due to the way carbon atoms are attached to one another (Katsnelson 2007). Graphite is one of the oldest known pure forms of carbon. Graphite poses a hexagonal layered structure consisting of six carbons attached in the form of a ring (Reich and Thomsen 2004), and Figure 7.1 depicts graphene's layered structure.
Carbon Allotropes-Based Nanodevices
Published in Shilpi Birla, Neha Singh, Neeraj Kumar Shukla, Nanotechnology, 2022
Sugandha Singhal, Meenal Gupta, Md. Sabir Alam, Md. Noushad Javed, Jamilur R. Ansari
Material scientists have succeeded in tailoring the structural and functional properties of existing materials to create new and modified versions by altering synthetic routes [1]. The two naturally occurring carbon allotropes are graphite with sp2 hybridized and diamond with sp3 hybridized carbon networks. Graphite is soft, ductile and conductive, whereas diamond is hard and insulating; thus, they show unique opposing properties. In 1985, the first synthetic carbon allotrope, zero dimension (0D) fullerene was discovered by Kroto et al. [2], followed by one dimension (1D) carbon nanotubes (sp hybridized) by Iijima [3] and zero dimension (2D) grapheme (sp2 hybridized) by Novoselov [4]. This extensive property of carbon helps in the fabrication of newer allotropes that could consist of extended rings or polygons [1].
High-temperature graphitization of coke and lithium storage properties of coke-based graphite
Published in International Journal of Coal Preparation and Utilization, 2023
Lipeng Wang, Zhiang Li, Chenxian Du, Yi Han, Jianguo Yang
With the rapid development of electric vehicles and portable electronic devices, higher requirements are placed on the performance of energy storage devices including endurance, safety, and reliability (Shi et al. 2018; Tian et al. 2020). Lithium-ion batteries are widely recognized for their excellent electrochemical performances such as high energy density, no memory effect, and long cycle life (Ding et al. 2019; Fan et al. 2020). Graphite with a layered structure formed by stacking carbon planes. It is favored for its low electrode potential, high specific capacity, and environmental friendliness, and it is used as a mainstream anode material for lithium-ion batteries (Cameán et al. 2010; Jara et al. 2019; Wang et al. 2020; Wu et al. 2017). In recent years, the demand for graphite has risen sharply, and the price of natural graphite remains high due to the uneven distribution of resources and difficulty in separation and purification (Qiu et al. 2022). Anthracite, bituminous coal, and other coal-derived carbon materials are often used to prepare coal-based graphite because of their high-fixed carbon content and aromatic ring structure similar to graphite, making coal-based graphite a type of artificial graphite with abundant raw resources and low production cost. Coal-based graphite with different microstructures can be obtained by adjusting the preparation process.
Tuning diamond electronic properties for functional device applications
Published in Functional Diamond, 2022
Anliang Lu, Limin Yang, Chaoqun Dang, Heyi Wang, Yang Zhang, Xiaocui Li, Hongti Zhang, Yang Lu
Pure diamond is a crystal consisting of sp3 hybridized carbon atoms. It has ultra-high hardness but is brittle and has a poor electrical conductivity. In contrast with diamond, graphite with sp2 bonding is soft and electrically conductive. Researchers have been looking for new carbon materials which show good electrical conductivity like graphite and high hardness like diamond. Zhang et al. [94] synthesized amorphous carbon material with a high fraction of sp3. The new carbon materials are semiconducting with a bandgap range of 1.5–2.2 eV, which are smaller than that of diamond and comparable to that of the widely used amorphous silicon. These materials also show good mechanical properties such as high highness and strength, such that the newly synthesized carbon material can even scratch the (001) surface of diamond. The same year, S. Zhang et al. [95] obtained some other semiconducting amorphous carbon materials with band gaps of 0.1-0.3 eV and isotropic super hardness and toughness. Shang et al. [96] successfully synthesized millimeter-sized, transparent, and nearly pure sp3 (up to 97.1%) amorphous carbon for the first time, as shown in Figure 5(b). This material consists of many randomly oriented clusters with diamond-like short-/medium-range order and possesses the highest hardness, elastic modulus, and thermal conductivity among all the known amorphous material. These materials also exhibit a wide range of tunable optical bandgap from 1.85 to 2.79 eV.
Systematic Component Investigation of the Steady-State High-Temperature In-Pile Nuclear Thermal Propulsion Experimental Test Bed
Published in Nuclear Technology, 2022
Tyler R. Steiner, Richard H. Howard
The heater shell was made from rigid POCO graphite. Graphite is electrically conductive. The graphite shell was electrically insulated from the heater’s current path through the use of the ceramic crucible. However, the ceramic crucible materials’ dielectric properties are known to degrade at elevated temperatures or current levels. For the trials detailed in this work, this phenomenon could be sufficient to create a parallel electrical circuit that shunted power through the heater shell, resulting in electrical fluctuations. A test was completed without the graphite shell to test this idea. Without the shell, the thermal energy is transferred via radiative heat transfer through the vacuum to a thermocouple suspended near the ceramic crucible. Lower recorded temperatures were observed for a given power input than in cases that used an instrumented shell. The thermal energy generated was transported less effectively through a vacuum to the thermocouple than conductively through a graphite shell. The runs with and without a shell used high-density magnesia.