Phase transitions and kinetic properties of gold nanoparticles confined between two-layer graphene nanosheets |
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| Institution: | 1. State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing 210009, China;2. College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China;3. School of Chemistry and Chemical Engineering, Yancheng Institute of technology, Yancheng 224051, China;4. Jinling High School, Nanjing 210005, China;1. Department of Electrical Engineering, Hsiuping University of Science and Technology, Taichung 412, Taiwan;2. Department of Applied Physics, Tunghai University, Taichung 407, Taiwan;3. iSentek Ltd., Advanced Sensor Laboratory, New Taipei City 221, Taiwan;4. Department of Physics, National Chung Cheng University, Chia-Yi 621, Taiwan;1. Sakarya University, Faculty of Arts and Sciences, Department of Physics, 54187 Sakarya, Turkey;2. Scientific and Technological Research Application and Research Center, Sinop University, 57000 Sinop, Turkey;1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, PR China;2. National Energy Center for Coal to Clean Fuels, Synfuels China Co., Ltd., Huairou District, Beijing 101400, PR China;3. University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, PR China;4. Physics Department, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia;5. K.A. CARE Energy Research & Innovation Center at Dhahran, Dhahran 31261, Saudi Arabia;1. Department of Physics, CCEN, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB, Brazil;2. Department of Physics, Universidade Federal de São Carlos, 13565-905 São Carlos, SP, Brazil;3. LIEC - Department of Chemistry, Universidade Federal de São Carlos, 13565-905 São Carlos, SP, Brazil;4. Institute of Chemistry, Universidade Estadual Paulista – Unesp, 14801-907 Araraquara, SP, Brazil |
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| Abstract: | The thermodynamic and kinetic behaviors of gold nanoparticles confined between two-layer graphene nanosheets (two-layer-GNSs) are examined and investigated during heating and cooling processes via molecular dynamics (MD) simulation technique. An EAM potential is applied to represent the gold–gold interactions while a Lennard–Jones (L–J) potential is used to describe the gold–GNS interactions. The MD melting temperature of 1345 K for bulk gold is close to the experimental value (1337 K), confirming that the EAM potential used to describe gold–gold interactions is reliable. On the other hand, the melting temperatures of gold clusters supported on graphite bilayer are corrected to the corresponding experimental values by adjusting the εAu–C value. Therefore, the subsequent results from current work are reliable. The gold nanoparticles confined within two-layer GNSs exhibit face center cubic structures, which is similar to those of free gold clusters and bulk gold. The melting points, heats of fusion, and heat capacities of the confined gold nanoparticles are predicted based on the plots of total energies against temperature. The density distribution perpendicular to GNS suggests that the freezing of confined gold nanoparticles starts from outermost layers. The confined gold clusters exhibit layering phenomenon even in liquid state. The transition of order–disorder in each layer is an essential characteristic in structure for the freezing phase transition of the confined gold clusters. Additionally, some vital kinetic data are obtained in terms of classical nucleation theory. |
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| Keywords: | Gold nanoparticle Graphene nanosheet Phase transition Molecular dynamics simulation |
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