Structural and electronic properties of 2D-activated carbon sheet
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Carbon Letters https://doi.org/10.1007/s42823-020-00177-3
ORIGINAL ARTICLE
Structural and electronic properties of 2D‑activated carbon sheet Ratnesh Kumar1 · Abhishek Kumar1 · B. Keshav Rao2 · Ambrish K. Srivastava3 · Mohan L. Verma2 · Neeraj Misra1 Received: 29 March 2020 / Revised: 6 July 2020 / Accepted: 11 August 2020 © Korean Carbon Society 2020
Abstract A simulation based (DFT) study is performed on activated 2D-carbon sheet without and with vacancies of central carbon atoms, and explored the electronic properties. The inter-atomic distance at the center of activated carbon sheet is gradually increased with increasing number of vacancies. We get lower binding energy with three vacancies, and higher without a vacancy. A covalent bond is found between C–C atoms, density of states exhibit a semiconductor nature of a system without vacancy, and metallic nature in the presence of vacancies. There are higher peaks of resultant anti-bonding states with three vacancy system and it exhibits higher amorphous nature which causes higher electron concentration, mobility and higher electrical conductivity. Keywords Activated carbon · Density functional theory · SIESTA · PDOS · DOS · COOP
1 Introduction Carbon-based materials are found in different forms viz. diamond, graphene, carbon nanotubes, nanofibers, amorphous carbon, activated carbon, etc. Among these, activated carbon has a wider scope of research due to enormous applications in liquid and gas treatment [1], metal selection [2], gold purification [3], medicine [4], waste treatments [5], electrodes, sensors [6], energy storage and conversion systems [7–12]. In the 1950s, Rosalind Franklin produced the structure of carbon by the pyrolysis of organic materials and classified into a graphitizing and non-graphitizing model [13]. Graphitization is observed with hexagonal rings of carbon, in non-graphitization; many hexagonal rings joined together along with pentagonal and heptagonal rings give Activated carbon. The ratio of pentagons/heptagons to hexagons is approximately 1:50 and this structure is relatively hard but extremely stable as compared to other carbons [14–17]. * Neeraj Misra [email protected] 1
Department of Physics, University of Lucknow, Lucknow, UP, India
2
Department of Applied Physics, FET-SSGI Shri Shankaracharya Technical Campus, Junwani, Bhilai, CG, India
3
Department of Physics, Deen Dayal Upadhyaya Gorakhpur University, Gorakhpur, UP, India
Among all the carbon materials, activated carbon exhibits the largest specific surface area with increased high porosity to adsorbents having a low cost [1, 9, 12, 18–20]. It removes waste water contaminants, pollutant from liquids and gases because of a large amorphous structure for adsorbent, high surface activity and chemical stability [21, 22]. Activated carbon is produced from organic precursors such as wood, rice husk, fruit shells, polymers, lignite, anthracite, brown coal, and petrochemical products [23, 24] either by physical activation or chemical activation [25]. The physical metho
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