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Ceramic-Supported Composite Membranes for Pervaporation
Published in Stephen Gray, Toshinori Tsuru, Yoram Cohen, Woei-Jye Lau, Advanced Materials for Membrane Fabrication and Modification, 2018
The discovery of graphene triggered the research on two-dimensional (2D) materials in related fields of physics, materials science, and chemistry. The unique feature of 2D materials, atomic thickness, enabled them as emerging building blocks for developing high-performance separation membranes by minimizing the membrane thickness to maximize the permeate flux (Liu et al., 2016). As an important derivative of graphene, GO is regarded as the most promising candidate for 2D-material membranes owing to its easy fabrication and processing, as well as abundant functional groups. Generally, the GO nanosheets are assembled into laminar membranes consisting of interlayer galleries for molecular separation. These GO membranes have shown excellent separation performance for water purification, solvent dehydration, ions separation, and gas separation (Liu et al., 2015b).
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
A group of physicists from Manchester University led by Andre Geim and Kostya Novoselov paved the way to the discovery of graphene in 2004 from graphite (Novoselov et al. 2005). Graphene, a wonder material of 21st century, possesses massive strength, high electrical conductivity, transparency, and flexibility (Edwards and Coleman 2013). This innate ability of graphene makes them a suitable material in the bio-medicine field, optical-based device, water treatment applications, fuel cells, super capacitors, batteries, etc. (Raghavan et al. 2017). This includes applications in the field of bio-medicine, optical-based device, water treatment applications, fuel cells, super capacitors, batteries, etc. (Raghavan et al. 2017). Graphene contains carbon atoms with sp2 hybridization arranged in a hexagonal honeycomb lattice with p-orbitals above and below the plane of the sheet which are partially filled (Edwards and Coleman 2013). Graphene can be monoatomic or single-layered (one graphitic layer), bilayer (two graphitic layer), tri-layer (three graphitic layer), few-layer graphene (more than 5 layer up to 10 graphitic layer), multilayered graphene or thick graphene or nanocrystalline thin graphite (20–30 layers of graphene) (Bhuyan et al. 2016) as shown in Figure 7.2. There is zero bandgap between the conduction band and the valance band in monolayer graphene due to the half-filled p-orbitals, which permits the free electrons. The adjacent graphene layers in layered graphene have weak van der Waals interactions due the p bonds present between them (Yang et al. 2018).
Theoretical Considerations of 2D Materials in Energy Applications
Published in Ram K. Gupta, 2D Nanomaterials, 2022
Harsha Rajagopalan, Sumit Dutta, Sourabh Barua, Pawan Kumar Dubey, Jyotsna Chaturvedi, Laxmi Narayan Tripathi
The field of two-dimensional (2D) materials got much attention after the discovery of graphene leading to a noble prize.1 Bulk 2D materials can be used to prepare thin, mono/few-layer thick transition metal carbonitrides (MXenes), carbides, nitrides, oxides, and transition metal dichalcogenides (TMDCs).2,3 TMDCs are a class of 2D materials with the chemical formula MX2, where M represents a transition metal and X represents a chalcogen.4,3 TMDCs are one of the most studied materials that have been isolated in monolayer form and show promising results like direct bandgap, which is a desired optoelectronic property.5,6 Molybdenum- and tungsten-based TMDCs are quite popular as semiconductors, with bandgap ranging from visible to near-infrared.7 Different types of 2D materials are widely used for the study of energy storage and energy conversion devices. They mainly include solar energy storage, photovoltaics, piezoelectric, and thermoelectric devices.8,9 Nanostructured 2D materials possess unique properties like high surface areas, tunable bandgap leading to superior optoelectronic properties. The fact that the 2D materials can mechanically be exfoliated from bulk single crystal and transferred to any desired substrates2,10 make them invaluable. Raman spectroscopy is an important tool to characterize the number of layers of 2D materials.11 Graphene is one of the heavily used 2D materials for the energy application industry due to its unique properties like large surface area and a high electrochemical performance rate. The discovery of graphene, experimentally by Andre Geim and Konstantin Novoselov in 200412 highlighted the 2D materials for various applications. Since graphene doesn’t have any bandgap, much effort has been made to find 2D materials that have a bandgap.5
Computation of some important degree-based topological indices for γ- graphyne and Zigzag graphyne nanoribbon
Published in Molecular Physics, 2023
Abdul Hakeem, Asad Ullah, Shahid Zaman
Numerous allotropes are produced when neighbouring carbon atoms hybridise at the sp3, sp2, or sp levels to create single, double, or even triple bonds. Graphite and diamond are the two most well-known carbon allotropes formed exclusively of carbon atoms that have undergone sp2 and sp3 hybridisation. [39–45]. Carbon allotropes exhibit distinctive physical characteristics because of the special pairing and arrangement of several types of bonds with varying lengths, strengths, geometries, and electronic properties. For instance, graphite is opaque and soft. A tremendous amount of research has gone into creating novel carbon allotropes, For example, fullerene (which obtained the Nobel Prize in Chemistry in 1996) [46], carbon nanotubes [42], graphene (which got the Nobel Prize in Physics in 2010) [47] a chain of biphenylene [48] and Carbon (which awarded the Nobel Prize in Physics in 2010 [49,50]. Two-dimensional (2D) carbon allotropes of Carbon are known as graphynes. The discovery of graphene inaugurated a new era of quantum technology and 2D materials. Researchers have been putting efforts into synthesising a novel carbon form termed graphyne for over a decade but with no success. Recently, some researchers have made a breakthrough in generating Carbon's elusive allotrope [51] and solved a long-standing problem in the field of carbon materials. This wonder material is created in such a way that it could rival the conductivity of graphene, but with control. These results opened new ways of research in the fields of semiconductor, electronics and optics.
Science of 2.5 dimensional materials: paradigm shift of materials science toward future social innovation
Published in Science and Technology of Advanced Materials, 2022
Hiroki Ago, Susumu Okada, Yasumitsu Miyata, Kazunari Matsuda, Mikito Koshino, Kosei Ueno, Kosuke Nagashio
The discovery of graphene opened up a new research field — 2D materials. There are a number of 2D materials with different compositions: transition metal dichalcogenides (TMDCs), hexagonal boron nitride (hBN), and monoelement atomic sheets including silicene (Si), germanene (Ge), stanene (Sn), and black phosphorous (P) [4,5]. Theoretically, more than 1800 types of 2D crystals are predicted [6]. These 2D materials show unique physical properties that strongly depend on their chemical compositions and the number of layers. For example, molybdenum disulfide (MoS2) has an indirect band gap in the bulk crystal, but the monolayer form shows a direct bandgap in the visible range. Monolayer MoS2 also exhibits valley freedom and piezoelectricity. Figure 1 summarizes the research trends of 2D materials and the expected future research directions. Many exciting findings and achievements based on 2D materials have been reported. Therefore, as shown in the inset of Figure 1, the number of scientific publications has increased with time, reflecting this increased interest in 2D materials.
A first principle study to investigate structural, electronic and optical properties of pristine and valency comparable Co, P decorated graphene like boron nitride (BN) nanosheets
Published in Phase Transitions, 2022
Md Kamal Hossain, Debashis Roy, Farid Ahmed
Two-dimensional nanomaterials open a new window in material science and engineering after the discovery of graphene by teamwork in the last decade[1]. The large volume-to-surface ratio of two-dimensional (2D) nanomaterials provides considerable outstanding properties with various applications in different fields of science and technology. This unusual property of 2D nanomaterials introduce them in a very different way from other forms of nanomaterial (0D, 1D and 3D) and their bulk counterparts, which explored a virgin and profound way of enhancing the abundance of new types of 2D nanomaterials in science and technology for their practical uses in multidisciplinary sectors[2–4]. For this purpose, graphene-like boron nitride nanosheets (BNNSs) took the attention considerably to the researchers[4–9].