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Catalytic Properties of Defect-Laden 2D Material from First-Principles

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Date Issued:
2019
Abstract/Description:
Two dimensional (2D) materials offer excellent opportunities for application as catalysts for energy needs. Their catalytic activity depends on the nature of defects, their geometry and their electronic structure. It thus important that the characteristics of defect-laden 2D materials be understood at the microscopic level. My dissertation focuses on theoretical and computational studies of several novel nanoscale materials using state-of-the-art techniques based on density functional theory (DFT) with the objective of understanding the microscopic factors that control material functionality.My work has helped establish defect-laden hexagonal boron nitride (dh-BN) as a promising metal-free catalyst for CO2 hydrogenation. Firstly, I showed how small molecules (H2, CO, CO2) interacting with several kinds of defects in dh-BN (with nitrogen or boron vacancy, boron substituted for nitrogen, Stone-Wales defect). I analyzed binding energies and electronic structures of adsorption of molecules on dh-BN to predict their catalytic activities. Then by computational efforts on reaction pathways and activation energy barriers, I found that vacancies induced in dh-BN can effectively activate the CO2 molecule for hydrogenation, where activation occurs through back-donation to the ?* orbitals of CO2 from frontier orbitals (defect state) of the h-BN sheet localized near a nitrogen vacancy (VN). Subsequent hydrogenation to formic acid (HCOOH) and methanol (CH3OH), indicating dh-BN (VN) an excellent metal-free catalyst for CO2 reduction, which may serve as a solution for global energy and sustainability.At the same time, I studied critical steps of the catalytic processes from carbon monoxide and methanol to higher alcohol on single-layer MoS2 functionalized with small Au nanoparticle, indicating C-C coupling feasible on MoS2-Au13, which led to production of acetaldehyde (CH3CHO). Whereas a bilayer 31-atom cluster of gold on MoS2 show excellent catalytic performance on CO hydrogenation to methanol through two effective pathways
Title: Catalytic Properties of Defect-Laden 2D Material from First-Principles.
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Name(s): Jiang, Tao, Author
Rahman, Talat, Committee Chair
Stolbov, Sergey, Committee Member
Blair, Richard, Committee Member
Tetard, Laurene, Committee Member
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2019
Publisher: University of Central Florida
Language(s): English
Abstract/Description: Two dimensional (2D) materials offer excellent opportunities for application as catalysts for energy needs. Their catalytic activity depends on the nature of defects, their geometry and their electronic structure. It thus important that the characteristics of defect-laden 2D materials be understood at the microscopic level. My dissertation focuses on theoretical and computational studies of several novel nanoscale materials using state-of-the-art techniques based on density functional theory (DFT) with the objective of understanding the microscopic factors that control material functionality.My work has helped establish defect-laden hexagonal boron nitride (dh-BN) as a promising metal-free catalyst for CO2 hydrogenation. Firstly, I showed how small molecules (H2, CO, CO2) interacting with several kinds of defects in dh-BN (with nitrogen or boron vacancy, boron substituted for nitrogen, Stone-Wales defect). I analyzed binding energies and electronic structures of adsorption of molecules on dh-BN to predict their catalytic activities. Then by computational efforts on reaction pathways and activation energy barriers, I found that vacancies induced in dh-BN can effectively activate the CO2 molecule for hydrogenation, where activation occurs through back-donation to the ?* orbitals of CO2 from frontier orbitals (defect state) of the h-BN sheet localized near a nitrogen vacancy (VN). Subsequent hydrogenation to formic acid (HCOOH) and methanol (CH3OH), indicating dh-BN (VN) an excellent metal-free catalyst for CO2 reduction, which may serve as a solution for global energy and sustainability.At the same time, I studied critical steps of the catalytic processes from carbon monoxide and methanol to higher alcohol on single-layer MoS2 functionalized with small Au nanoparticle, indicating C-C coupling feasible on MoS2-Au13, which led to production of acetaldehyde (CH3CHO). Whereas a bilayer 31-atom cluster of gold on MoS2 show excellent catalytic performance on CO hydrogenation to methanol through two effective pathways
Identifier: CFE0007823 (IID), ucf:52822 (fedora)
Note(s): 2019-12-01
Ph.D.
Sciences,
Doctoral
This record was generated from author submitted information.
Subject(s): 2D materials -- Catalyst -- DFT
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0007823
Restrictions on Access: public 2019-12-15
Host Institution: UCF

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