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Ugwumadu C, Thapa R, Nepal K, Gautam A, Al-Majali Y, Trembly J, Drabold DA. Self-Assembly and the Properties of Micro-Mesoporous Carbon. J Chem Theory Comput 2024; 20:1753-1762. [PMID: 37326598 DOI: 10.1021/acs.jctc.3c00394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
This study introduces a new approach for constructing atomistic models of nanoporous carbon by randomly distributing carbon atoms and pore volumes in a periodic box and then using empirical and ab initio molecular simulation tools to find the suitable energy-minimum structures. The models, consisting of 5000, 8000, 12000, and 64000 atoms, each at mass densities of 0.5, 0.75, and 1 g/cm3, were analyzed to determine their structural characteristics and relaxed pore size distribution. Surface analysis of the pore region revealed that sp atoms exist predominantly on surfaces and act as active sites for oxygen adsorption. We also investigated the electronic and vibrational properties of the models, and localized states near the Fermi level were found to be primarily situated at sp carbon atoms through which electrical conduction may occur. Additionally, the thermal conductivity was calculated using heat flux correlations and the Green-Kubo formula, and its dependence on pore geometry and connectivity was analyzed. The behavior of the mechanical elasticity moduli (Shear, Bulk, and Young's moduli) of nanoporous carbons at the densities of interest was discussed.
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Affiliation(s)
- C Ugwumadu
- Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute (NQPI), Ohio University, Athens, Ohio 45701, United States
| | - R Thapa
- Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute (NQPI), Ohio University, Athens, Ohio 45701, United States
| | - K Nepal
- Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute (NQPI), Ohio University, Athens, Ohio 45701, United States
| | - A Gautam
- Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute (NQPI), Ohio University, Athens, Ohio 45701, United States
| | - Y Al-Majali
- Department of Mechanical Engineering, Institute for Sustainable Energy and the Environment (ISEE), Ohio University, Athens, Ohio 45701, United States
| | - J Trembly
- Department of Mechanical Engineering, Institute for Sustainable Energy and the Environment (ISEE), Ohio University, Athens, Ohio 45701, United States
| | - D A Drabold
- Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute (NQPI), Ohio University, Athens, Ohio 45701, United States
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Ugwumadu C, Olson Iii R, Smith NL, Nepal K, Al-Majali Y, Trembly J, Drabold DA. Computer simulation of carbonization and graphitization of coal. Nanotechnology 2023. [PMID: 38016446 DOI: 10.1088/1361-6528/ad1058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
This study describes computer simulations of carbonization and graphite formation, including the effects of hydrogen, nitrogen, oxygen, and sulfur. We introduce a novel technique to simulate carbonization, ``Simulation of Thermal Emission of Atoms and Molecules (STEAM)," designed to elucidate volatile outgassing and density variations in the intermediate material during carbonization. The investigation analyzes the functional groups that endure through high-temperature carbonization and examines the graphitization processes in carbon-rich materials containing non-carbon "impurity elements". The physical, vibrational, and electronic attributes of impure amorphous graphite are analyzed, and the impact of nitrogen on electronic conduction is investigated.
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Affiliation(s)
- Chinonso Ugwumadu
- Ohio University, Ohio University, Athens, Ohio, 45701-2978, UNITED STATES
| | - Rudolph Olson Iii
- CONSOL Innovations LLC, 1142 Co Hwy 39 building 2, Triadelphia, West Virginia, 26059, UNITED STATES
| | - Natasha L Smith
- CONSOL Innovations LLC, 1142 Co Hwy 39 building 2, Triadelphia, West Virginia, 26059, UNITED STATES
| | - Kishor Nepal
- Ohio University, Ohio University, Athens, Ohio, 45701-2978, UNITED STATES
| | - Yahya Al-Majali
- Ohio University, Ohio University, Athens, Ohio, 45701-2978, UNITED STATES
| | - Jason Trembly
- Ohio University, Ohio University, Athens, Ohio, 45701-2978, UNITED STATES
| | - David A Drabold
- Ohio University, Ohio University, Athens, Ohio, 45701-2978, UNITED STATES
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