subject:(Synchrotron powder diffraction)

University of Sydney

1. Mohamed, Zakiah. Relationships Among Structure, Magnetism and State of Charge in Positive Electrode Materials for Metal-Ion Batteries .

Degree: 2015, University of Sydney

URL: http://hdl.handle.net/2123/14438

► Polyanionic framework materials containing 3d transition metals such as iron, cobalt and manganese are attractive candidates as electrodes in lithium and sodium ion batteries due… (more)

▼ Polyanionic framework materials containing 3d transition metals such as iron, cobalt and manganese are attractive candidates as electrodes in lithium and sodium ion batteries due to their thermal stability, long cycle life and environmental friendliness. LiFePO4 is already used in some commercial lithium ion batteries as a positive electrode material where these are key attributes, but it still has lower energy density and higher costs compared to the more commonly used LiCoO2. This thesis describes a combined physical properties and magnetic structures some of these materials, aimed at improving our understanding of their solid-state chemistry, and ultimately their performance as battery materials by relating those physical and magnetic properties to the state of charge of the battery. A variety of polyanionic materials including phosphates, pyrophosphates and silicates were prepared using solid-state synthesis. All compounds were intensively characterized using specific heat capacity and magnetic measurements, X-ray, neutron and synchrotron X-ray diffraction techniques. Low-temperature neutron diffraction was used to solved and refined the magnetic structures. During the lithium extraction process, the magnetic properties can vary significantly because it involve redox reaction of transition metals. Measuring the magnetic properties of working electrode materials can therefore potentially provide information about local structural changes including the introduction of defects, decomposition and phase segregation. The magnetic properties of chemically delithiated samples were also studied so that they could be used as reference materials. In the first part of the thesis, the phosphates family AM1-xM′xPO4 (A = Li, Na; M = Mn, Fe; M′ = Zn, Mn, Fe) are intensively studied. These phosphates are modified in two ways: by doping with magnetic and non-magnetic transition metals. It was found that all compounds exhibit antiferromagnetic ordering at low temperatures, but the nature and ordering temperatures depend on doping. In the course of this work, the magnetic structures of two types of sodium phosphate were determined for the first time,triphylite and maricite NaFePO4. The triphylite type showed similar crystal and magnetic properties as LiFePO4, while the maricite type demonstrated a transition from commensurate (T < 12 K) to incommensurate (12 < T < 13 K) magnetic phases. A spin-flop transition in the commensurate phase was also observed. These results are discussed in the context of spin frustration on the Fe2+ sites. The second type of cathode material studied was the pyrophosphate A2M1-xM′xP2O7 (A = Li, Na; M = Fe; M′ = Co, Mn). Varying the compositions of these materials led to significant changes in crystallographic and electronic structure with remarkable effects on the magnetic properties and structures.The magnetic structures of Li2(Fe1-xCox)P2O7 and Na2(Fe1-xMnx)P2O7 solid solutions were explored in the course of this work. The crystal and magnetic structures of the silicates γ-Li2MnSiO4 and…

Subjects/Keywords: Cathode materials; Magnetic properties; Powder X-ray diffraction; Neutron powder diffraction; Magnetic structure; Synchrotron X-ray diffraction

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APA (6^th Edition):

Mohamed, Z. (2015). Relationships Among Structure, Magnetism and State of Charge in Positive Electrode Materials for Metal-Ion Batteries . (Thesis). University of Sydney. Retrieved from http://hdl.handle.net/2123/14438

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mohamed, Zakiah. “Relationships Among Structure, Magnetism and State of Charge in Positive Electrode Materials for Metal-Ion Batteries .” 2015. Thesis, University of Sydney. Accessed January 26, 2021. http://hdl.handle.net/2123/14438.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mohamed, Zakiah. “Relationships Among Structure, Magnetism and State of Charge in Positive Electrode Materials for Metal-Ion Batteries .” 2015. Web. 26 Jan 2021.

Vancouver:

Mohamed Z. Relationships Among Structure, Magnetism and State of Charge in Positive Electrode Materials for Metal-Ion Batteries . [Internet] [Thesis]. University of Sydney; 2015. [cited 2021 Jan 26]. Available from: http://hdl.handle.net/2123/14438.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mohamed Z. Relationships Among Structure, Magnetism and State of Charge in Positive Electrode Materials for Metal-Ion Batteries . [Thesis]. University of Sydney; 2015. Available from: http://hdl.handle.net/2123/14438

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of New South Wales

2. Chang, Fenfen. Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels.

Degree: Physics, 2017, University of New South Wales

URL: http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true

► Multiferroics exhibit tremendous potential in technological applications, of which the interplaybetween the ferro-/antiferromagnetic, ferroelectricity, and ferroelasticity can be manipulatedby external parameters such as electric or… (more)

▼ Multiferroics exhibit tremendous potential in technological applications, of which the interplaybetween the ferro-/antiferromagnetic, ferroelectricity, and ferroelasticity can be manipulatedby external parameters such as electric or magnetic fields and even can be created byproper control of internal parameters, such as oxygen-content, cation doping, and internalpressure. Invaluable insight into the multiferroicity can be provided by investigating the roleof such parameters in the crystallographic and magnetic structures of transition metal oxides.In this thesis, a comprehensive studies of contribution of oxygen-deficiencies and cation dopingto the various phases are presented, which utilize the neutron and synchrotron powderdiffraction.The multivalent nature of cobalt ions in SrCoO3􀀀d causes an oxygen-content dependentphase diagram. It is vital to determine the precise crystallographic and magnetic structure ofoxygen-vacancy ordered SrCoO3􀀀d , which provides prerequisite to reveal the mechanism ofits multiferroicity in the corresponding thin film samples. Using the neutron and synchrotronpowder diffraction techniques, the correct space group and precise magnetic structures aredetermined for the different oxygen-vacancy ordered phases: the brownmillerite SrCoO2:5,the tetragonal SrCoO2:875, and the cubic SrCoO3.Ferroelectricity can be induced by the canted spin configuration, which exists widely inthe frustrated spin systems. With such an expectation, Zn-substituted CuFe2O4 was studiedand a comprehensive phase diagram was built for Cu1􀀀xZnxFe2O4. Spin canting couldlead to a spin spiral phase which could possibly induce a multiferroic state as observed inCuFeO2. The purpose of this project was to further investigate the spin canting in ZndopedCuFe2O4 and elucidate the possibility of multiferroicity in this system. Furthermore,pure ZnFe2O4 is already an interesting highly frustrated spin system. Magnetite is the oldestknown magnet. As the first known multiferroics, the ferroelectricity in Fe3O4 is drivenby the Verwey transition. However, the microscopic origin of the Verwey transition in Fe3O4is still in debate. In order to obtain a deeper insight into the mechanism of the charge ordering,Cu-doped Fe3O4 was investigated using the high-resolution neutron and synchrotrondiffraction. The main emphasis was the stability of the Verwey transition with charge carrierdoping. Advisors/Committee Members: Ulrich, Clemens, Physics, Faculty of Science, UNSW, Sushkov, Oleg, Physics, Faculty of Science, UNSW.

Subjects/Keywords: Oxygen vacancy ordering; Neutron diffraction; Synchrotron powder diffraction; Verwey transition; Charge ordering

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APA (6^th Edition):

Chang, F. (2017). Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true

Chicago Manual of Style (16^th Edition):

Chang, Fenfen. “Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels.” 2017. Doctoral Dissertation, University of New South Wales. Accessed January 26, 2021. http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true.

MLA Handbook (7^th Edition):

Chang, Fenfen. “Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels.” 2017. Web. 26 Jan 2021.

Vancouver:

Chang F. Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels. [Internet] [Doctoral dissertation]. University of New South Wales; 2017. [cited 2021 Jan 26]. Available from: http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true.

Council of Science Editors:

Chang F. Search for novel multifunctional materials: a comprehensive neutron and synchrotron diffraction study on cobaltates and spinels. [Doctoral Dissertation]. University of New South Wales; 2017. Available from: http://handle.unsw.edu.au/1959.4/57563 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:43656/SOURCE02?view=true

University of Guelph

3. Emond, Vincent. Optimizing and Analyzing X-Ray Powder Diffraction of Orthosilicate Cathodes using a Combined Synchrotron X-Ray Diffraction and Absorption Spectroscopy Setup.

Degree: MS, Department of Physics, 2018, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/13005

► Lithium ion batteries have become ubiquitous in the modern world, powering devices such as cellular phones and vehicles. This thesis seeks to improve the powder… (more)

Subjects/Keywords: Lithium ion; battery; cathode; orthosilicate; xrd; pxrd; xanes; diffraction; x-ray; x ray; powder diffraction; synchrotron

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APA (6^th Edition):

Emond, V. (2018). Optimizing and Analyzing X-Ray Powder Diffraction of Orthosilicate Cathodes using a Combined Synchrotron X-Ray Diffraction and Absorption Spectroscopy Setup. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/13005

Chicago Manual of Style (16^th Edition):

Emond, Vincent. “Optimizing and Analyzing X-Ray Powder Diffraction of Orthosilicate Cathodes using a Combined Synchrotron X-Ray Diffraction and Absorption Spectroscopy Setup.” 2018. Masters Thesis, University of Guelph. Accessed January 26, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/13005.

MLA Handbook (7^th Edition):

Emond, Vincent. “Optimizing and Analyzing X-Ray Powder Diffraction of Orthosilicate Cathodes using a Combined Synchrotron X-Ray Diffraction and Absorption Spectroscopy Setup.” 2018. Web. 26 Jan 2021.

Vancouver:

Emond V. Optimizing and Analyzing X-Ray Powder Diffraction of Orthosilicate Cathodes using a Combined Synchrotron X-Ray Diffraction and Absorption Spectroscopy Setup. [Internet] [Masters thesis]. University of Guelph; 2018. [cited 2021 Jan 26]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/13005.

Council of Science Editors:

Emond V. Optimizing and Analyzing X-Ray Powder Diffraction of Orthosilicate Cathodes using a Combined Synchrotron X-Ray Diffraction and Absorption Spectroscopy Setup. [Masters Thesis]. University of Guelph; 2018. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/13005

4. Broux, Thibault. Caractérisations structurales in situ avancées d'oxydes dérivées de la pérovskite pour des applications électrochimiques à haute température : Advanced crystal characterization in situ of oxides related to perovskite for high temperature electrochemical devices.

Degree: Docteur es, Chimie, 2014, Rennes 1

URL: http://www.theses.fr/2014REN1S125

►

Ce travail de thèse se situe dans la thématique des oxydes dérivés de la pérovskite ayant des propriétés de conduction mixte tels que les structures… (more)

▼

Ce travail de thèse se situe dans la thématique des oxydes dérivés de la pérovskite ayant des propriétés de conduction mixte tels que les structures de type K2NiF4, les pérovskites doubles et la brownmillérite. Cette aptitude à conduire à la fois l'oxygène et les électrons présente un intérêt pour des dispositifs électrochimiques fonctionnant à haute température et notamment en tant qu'électrode pour les piles à combustible à oxyde solide. Plus précisément, cette thèse concerne la synthèse et l'étude cristallochimique avancée de la réactivité de ces matériaux essentiellement par les grands instruments par le biais de la diffraction de neutrons (NPD) et des rayons X synchrotron. Le travail préliminaire à ces études implique de la synthèse inorganique par voie solide ou par voie sol-gel, l'analyse thermogravimétrique et la titration iodométrique. Des cellules de réactivité originales ont été développées spécialement à l'ISCR pour l'étude in situ du comportement redox sous différents flux gazeux et en fonction de la température à la fois dans le cadre de la diffraction des neutrons et rayons X synchrotron. L'étude in situ par NPD des composés La2-xSrxMnO4±δ où x = 2,0 et x = 0,8 qui dérivent du composé de cathode de référence La1-xSrxMnO3 a permis de suivre l'évolution structurale en fonction du δ en conditions réductrices pour x = 2,0 et en conditions oxydantes pour x = 0,8. L'étude DRX synchrotron de Pr2NiO4,22 a permis de mettre en évidence la symétrie monoclinique à température ambiante alors que les études précédentes annonçaient une symétrie orthorhombique. Les variations structurales notamment la transition vers la phase HTT sont accompagnées d'une modulation incommensurable qui persiste jusqu'à au moins 900 °C. L'étude des pérovskites doubles NdBaCo2−xMnxO5+δ où 0 ≤ x ≤ 2 a permis de montrer que ces matériaux présentent des conductivités électriques totales très prometteuses pour des applications en tant que cathode de SOFC. De plus, la confrontation de la dynamique moléculaire et de la NPD combinée à la MEM pour le composé x = 0 a permis d'élucider le mécanisme de diffusion de l'oxygène dans cette famille de composés. L'étude par NPD de la réduction de LaSrFeCoO6 vers LaSrFeCoO5 de structure brownmillérite a permis de mettre en évidence que la structure réduite persiste à haute température et l'évolution de la mise en ordre des moments magnétiques lors du refroidissement de LaSrFeCoO5.

This thesis is focused on oxides related to perovskite such as K2NiF4 structure-type, double perovskite and brownmillerite with mixed conduction properties. This ability to conduct both oxygen ions and electrons is relevant for electrochemical devices operating at high temperature, particularly as an electrode for solid oxide fuel cell. Specifically, this thesis deals with the synthesis and advanced crystal structure characterization of the reactivity of these materials mainly through large scale facilities by means of neutron powder diffraction (NPD) and X-ray synchrotron. Preliminary work in these studies involves inorganic…

Advisors/Committee Members: Bahout, Mona (thesis director), Hernandez, Olivier (thesis director).

Subjects/Keywords: Oxydes; Conducteurs mixtes; Diffraction sur poudre; Grands instruments; Diffraction de neutrons sur poudre; Synchrotron; Sofc; Électrode de SOFC; Méthode d'entropie maximale; Oxides; Mixed conductors; Powder diffraction; Large scale facilities; Neutron powder diffraction; Synchrotron; Sofc; SOFC electrodes; Maximum entropy method

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Broux, T. (2014). Caractérisations structurales in situ avancées d'oxydes dérivées de la pérovskite pour des applications électrochimiques à haute température : Advanced crystal characterization in situ of oxides related to perovskite for high temperature electrochemical devices. (Doctoral Dissertation). Rennes 1. Retrieved from http://www.theses.fr/2014REN1S125

Chicago Manual of Style (16^th Edition):

Broux, Thibault. “Caractérisations structurales in situ avancées d'oxydes dérivées de la pérovskite pour des applications électrochimiques à haute température : Advanced crystal characterization in situ of oxides related to perovskite for high temperature electrochemical devices.” 2014. Doctoral Dissertation, Rennes 1. Accessed January 26, 2021. http://www.theses.fr/2014REN1S125.

MLA Handbook (7^th Edition):

Broux, Thibault. “Caractérisations structurales in situ avancées d'oxydes dérivées de la pérovskite pour des applications électrochimiques à haute température : Advanced crystal characterization in situ of oxides related to perovskite for high temperature electrochemical devices.” 2014. Web. 26 Jan 2021.

Vancouver:

Broux T. Caractérisations structurales in situ avancées d'oxydes dérivées de la pérovskite pour des applications électrochimiques à haute température : Advanced crystal characterization in situ of oxides related to perovskite for high temperature electrochemical devices. [Internet] [Doctoral dissertation]. Rennes 1; 2014. [cited 2021 Jan 26]. Available from: http://www.theses.fr/2014REN1S125.

Council of Science Editors:

Broux T. Caractérisations structurales in situ avancées d'oxydes dérivées de la pérovskite pour des applications électrochimiques à haute température : Advanced crystal characterization in situ of oxides related to perovskite for high temperature electrochemical devices. [Doctoral Dissertation]. Rennes 1; 2014. Available from: http://www.theses.fr/2014REN1S125

Australian National University

5. Fullagar, Wilfred K. Molecular Fullerides .

Degree: 1997, Australian National University

URL: http://hdl.handle.net/1885/47059

► The closed shell structures of certain all-carbon fragments originally observed in mass spectroscopy experiments leads to the enhanced stability of these species, known as fullerenes,… (more)

Subjects/Keywords: fullerides; fullerenes; C60; superconductivity; near-infrared spectroscopy; neutron scattering; synchrotron; X-ray powder diffraction; vibrational analysis; liquid ammonia titration

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APA (6^th Edition):

Fullagar, W. K. (1997). Molecular Fullerides . (Thesis). Australian National University. Retrieved from http://hdl.handle.net/1885/47059

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Fullagar, Wilfred K. “Molecular Fullerides .” 1997. Thesis, Australian National University. Accessed January 26, 2021. http://hdl.handle.net/1885/47059.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Fullagar, Wilfred K. “Molecular Fullerides .” 1997. Web. 26 Jan 2021.

Vancouver:

Fullagar WK. Molecular Fullerides . [Internet] [Thesis]. Australian National University; 1997. [cited 2021 Jan 26]. Available from: http://hdl.handle.net/1885/47059.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Fullagar WK. Molecular Fullerides . [Thesis]. Australian National University; 1997. Available from: http://hdl.handle.net/1885/47059

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

6. Maimaitiyili, Tuerdi. Phase transformation and stability studies of the Zr-H system .

Degree: Malmö University. Faculty of Technology and Society, 2015, Malmö University

URL: http://hdl.handle.net/2043/19765

► Zirconium alloys are widely used in the nuclear industry because of their high strength, good corrosion resistance and low neutron absorption cross-section. Zirconium has a… (more)

▼ Zirconium alloys are widely used in the nuclear industry because of their high strength, good corrosion resistance and low neutron absorption cross-section. Zirconium has a strong affinity for hydrogen, however, and if hydrogen concentration builds up, the material will gradually degrade. In one class of such hydrogen caused degradation, called hydride induced embrittlement, hydrogen chemically reacts with zirconium forming one, or several, crystal phases of zirconium hydride. These hydrides play a primary, but sometime not fully understood, role in crack initiation and propagation within these materials. Despite the fact that hydride induced embrittlement in zirconium have been studied for several decades, there are still some unresolved issues. It has been the aim of the research presented in this thesis to provide the research community with new and updated data of the hydrides themselves in order to aid further studies within the field of hydride induced embrittlement in general, and the mechanism of delayed hydride cracking in particular. To that end, the research presented here proceeded, in short, as follows: First, zirconium hydride powder, of well defined hydrogen concentration, was produced from commercial grade zirconium. This powder was subjected to heat treatment and the hydride phases were characterized both in situ and ex situ using neutron, synchrotron X-ray, and conventional laboratory X-ray based diffraction techniques. Next, most of the low-pressure zirconium hydride phases were produced under hydrogen/argon atmosphere from commercial grade zirconium powder. This process was simultaneously monitored and recorded in real time using synchrotron X-ray diffraction. These experiments have produced new data of the behavior of different hydride phases during thermal treatment and in situ hydrogenation. For the first time all commonly reported zirconium hydride phases and the complete transformation between two different hydride phases were recorded with a single experimental arrangement. The phase transformation between δ and ε zirconium hydride was recorded in detail and presented. Finally, the controversial γ zirconium hydride was observed both in situ and ex situ and the preparation route, its crystal structure, and formation mechanisms were analyzed and presented.

Subjects/Keywords: Zirconium hydride; synchrotron X-ray diffraction; Nuclear materials; phase transformation; in-situ hydrogen charging; hydrogen related degradation; neutron diffraction; powder diffraction; Rietveld analysis; γ-ZrH; hydrogen embrittlement

…stability of γ-zirconium hydride by high-resolution neutron powder diffraction. Z. Wang, A… …Diffraction techniques . . . . . . 3.3 Powder diffraction . . . . . . . . 3.4 Materials… …synchrotron X-ray diffraction and neutron diffractions facilities. In addition, a series of… …accurate in situ studies. Neutron and synchrotron X-ray diffraction are two of the most widely… …First, zirconium hydride powder, of well defined hydrogen concentration, was produced from…

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APA (6^th Edition):

Maimaitiyili, T. (2015). Phase transformation and stability studies of the Zr-H system . (Thesis). Malmö University. Retrieved from http://hdl.handle.net/2043/19765

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Maimaitiyili, Tuerdi. “Phase transformation and stability studies of the Zr-H system .” 2015. Thesis, Malmö University. Accessed January 26, 2021. http://hdl.handle.net/2043/19765.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Maimaitiyili, Tuerdi. “Phase transformation and stability studies of the Zr-H system .” 2015. Web. 26 Jan 2021.

Vancouver:

Maimaitiyili T. Phase transformation and stability studies of the Zr-H system . [Internet] [Thesis]. Malmö University; 2015. [cited 2021 Jan 26]. Available from: http://hdl.handle.net/2043/19765.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Maimaitiyili T. Phase transformation and stability studies of the Zr-H system . [Thesis]. Malmö University; 2015. Available from: http://hdl.handle.net/2043/19765

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

7. Lu, Yongwu. Catalytic conversion of syngas to higher alcohols over Cu-Fe based catalysts.

Degree: PhD, Agricultural and Biological Engineering, 2014, Mississippi State University

URL: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10032014-105903/ ;

► Higher alcohol synthesis (HAS) from syngas or biomass-derived syngas is an important process for the production of oxygenate fuels, fuel additives and other intermediates… (more)

▼ Higher alcohol synthesis (HAS) from syngas or biomass-derived syngas is an important process for the production of oxygenate fuels, fuel additives and other intermediates for value-added chemical feedstock to produce medicine, cosmetics, lubricants, detergents, and polyesters. Chapter I reviews biomass to liquid fuels technology, higher alcohols being used as alternative fuels and fuel additives, the historical perspective and commercial status of higher alcohols, the catalyst system and the reaction mechanism for HAS from syngas. Chapter II discusses the Zn-Mn promoted Cu-Fe based catalyst that was synthesized by the co-precipitation method. The reaction temperature has been tested to study the influence on the catalytic performance. The maximal CO conversion rate was 72%, and the yield of alcohol and hydrocarbon was also very high. Cu was the active site for alcohol synthesis, iron carbide was the active site for olefin and paraffin synthesis. The reaction mechanism of HAS from syngas over Zn-Mn promoted Cu-Fe based catalyst was proposed. Chapter III documents the three-dimensionally ordered macroporous (3DOM) Cu-Fe catalyst developed using a glyoxylate route colloidal crystal template method. The high intrinsic activity was ascribed to three factors. First, the unique ordered structure has a large pore size and interconnected macroporous tunnels of the catalyst with a large accessible surface area to improve the catalytic activity. Second, a high density of uniformly distributed defective Cu⁰ and Fe₅C₂ nanoparticles derived from the glyoxylate route helps to provide abundant, active, and stable dual sites. Third, atomic steps on the Cu surface, induced by planar defects and lattice strain, serve as high-activity oxygenation sites. Active Fe₅C₂ chain-growth sites intimately surround the defective and strained form of the Cu surface, which results in a synergetic effect between the active and stable CuFe_xC_y dual site for HAS. In Chapter IV, in situ ambient pressure x-ray photoelectron spectroscopy and in situ synchrotron powder diffraction were applied to identify the active site of 3DOM Cu-Fe catalyst for HAS. The results show that after syngas pretreatment of the 3DOM Cu-Fe catalyst, Cu⁰ is the active oxygenation site for alcohol synthesis, and Fe₅C₂ is the active site for carbon chain growth. Advisors/Committee Members: Fei Yu (chair), Janice DuBien (committee member), Todd E. Mlsna (committee member), Judith A. Schneider (committee member), Radhakrishnan Srinivasan (committee member).

Subjects/Keywords: syngas; copper-iron catalyst; active site; co-precipitation; defect; three-dimensionally ordered macroporous; structure-activity relationship; in situ APXPS; in situ synchrotron powder diffraction; higher alcohol synthesis

…National Laboratory for his technical support on in situ synchrotron powder diffraction study. I… …137 4.2.3.6 In situ synchrotron powder diffraction ..................................138… …situ synchrotron powder diffraction study of 3DOM Cu2Fe1 catalyst… …133 4.2 Scheme of in situ synchrotron powder diffraction experimental setup .........139… …153 4.10 Temperature-resolved synchrotron powder diffraction patterns during the in situ…

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APA (6^th Edition):

Lu, Y. (2014). Catalytic conversion of syngas to higher alcohols over Cu-Fe based catalysts. (Doctoral Dissertation). Mississippi State University. Retrieved from http://sun.library.msstate.edu/ETD-db/theses/available/etd-10032014-105903/ ;

Chicago Manual of Style (16^th Edition):

Lu, Yongwu. “Catalytic conversion of syngas to higher alcohols over Cu-Fe based catalysts.” 2014. Doctoral Dissertation, Mississippi State University. Accessed January 26, 2021. http://sun.library.msstate.edu/ETD-db/theses/available/etd-10032014-105903/ ;.

MLA Handbook (7^th Edition):

Lu, Yongwu. “Catalytic conversion of syngas to higher alcohols over Cu-Fe based catalysts.” 2014. Web. 26 Jan 2021.

Vancouver:

Lu Y. Catalytic conversion of syngas to higher alcohols over Cu-Fe based catalysts. [Internet] [Doctoral dissertation]. Mississippi State University; 2014. [cited 2021 Jan 26]. Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10032014-105903/ ;.

Council of Science Editors:

Lu Y. Catalytic conversion of syngas to higher alcohols over Cu-Fe based catalysts. [Doctoral Dissertation]. Mississippi State University; 2014. Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10032014-105903/ ;

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Open Access Theses and Dissertations