51
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Kostestkyy P, Yu J, Gorte RJ, Mpourmpakis G. Structure–activity relationships on metal-oxides: alcohol dehydration. Catal Sci Technol 2014. [DOI: 10.1039/c4cy00632a] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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52
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Ewing CS, Bhavsar S, Veser G, McCarthy JJ, Johnson JK. Accurate amorphous silica surface models from first-principles thermodynamics of surface dehydroxylation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:5133-5141. [PMID: 24793021 DOI: 10.1021/la500422p] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Accurate atomically detailed models of amorphous materials have been elusive to-date due to limitations in both experimental data and computational methods. We present an approach for constructing atomistic models of amorphous silica surfaces encountered in many industrial applications (such as catalytic support materials). We have used a combination of classical molecular modeling and density functional theory calculations to develop models having predictive capabilities. Our approach provides accurate surface models for a range of temperatures as measured by the thermodynamics of surface dehydroxylation. We find that a surprisingly small model of an amorphous silica surface can accurately represent the physics and chemistry of real surfaces as demonstrated by direct experimental validation using macroscopic measurements of the silanol number and type as a function of temperature. Beyond accurately predicting the experimentally observed trends in silanol numbers and types, the model also allows new insights into the dehydroxylation of amorphous silica surfaces. Our formalism is transferrable and provides an approach to generating accurate models of other amorphous materials.
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Affiliation(s)
- Christopher S Ewing
- Department of Chemical and Petroleum Engineering, ‡Mascaro Center for Sustainable Innovation, University of Pittsburgh , Pittsburgh, Pennsylvania 15261, United States
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53
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Abdollahifar M. Synthesis and Characterisation of γ-Al2O3 with Porous Structure and Nanorod Morphology. JOURNAL OF CHEMICAL RESEARCH 2014. [DOI: 10.3184/174751914x13910938972748] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mesoporous γ-Al2O3 nanorods can be successfully synthesised using calcination of as-synthesised boehmite at 500 °C. The use of NaOH and KOH as pH adjusting agents in hydrothermal route on the synthesised samples are investigated in detail. X-ray powder diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, N2 adsorption/desorption, field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) are used to characterise the products. The TEM and FESEM micrographs show that the products were nanorod. According to our experimental results, the as-prepared γ-AlOOH and γ-Al2O3 possesses ordered mesoporosity and narrow pore-size distribution. The γ-Al2O3 prepared using KOH as pH adjusting regent show higher surface area compared with other samples prepared by NaOH.
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Affiliation(s)
- Mozaffar Abdollahifar
- Department of Chemical Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah 67131, Iran
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54
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Cai N, Liu Q, Tong X, Zhou G. X-ray photoelectron spectroscopy study of the passivation of NiAl(100) by water vapor. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:774-783. [PMID: 24417205 DOI: 10.1021/la4039649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The oxidation of NiAl(100) surfaces by water vapor is studied using X-ray photoelectron spectroscopy (XPS) to elucidate the effect of temperature and vapor pressure on the surface passivation mechanism of the NiAl alloy. The water-vapor oxidation at ambient temperature (25 °C) results in self-limiting Al(OH)3/Al2O3 bilayer film growth to a less extent of the limiting thickness regimes, in which the growth of the inner Al2O3 layer occurs via dehydration of the outer Al(OH)3 layer. The growth of the passivating overlayer at the ambient temperature depletes Al and forms a Ni-rich layer at the oxide/alloy interface that impedes supply of Al atoms to the outer surface for Al(OH)3 formation via the hydration reaction, whereby resulting in a more Al-deficient structure of the outer Al(OH)3 layer upon increasing the vapor pressure. In contrast, the water-vapor oxidation at 300 °C results in Al2O3 single-layer film growth to a larger limiting thickness without involving the transient hydroxide phase of Al(OH)3. It is shown that increasing the oxidation temperatures results in the formation of a more compact Al2O3 film owning to the enhanced bulk diffusion rate that maintains an adequate supply of Al atoms to the oxide/alloy interface to sustain the oxide film growth to the full extent of the limiting thickness.
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Affiliation(s)
- Na Cai
- Department of Mechanical Engineering & Multidisciplinary Program in Materials Science and Engineering, State University of New York , Binghamton, New York 13902, United States
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55
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Xia Y, Chen B, Jiao X, Chen D. Large-scale synthesis and formation mechanism study of basic aluminium sulfate microcubic crystals. Phys Chem Chem Phys 2014; 16:5866-74. [DOI: 10.1039/c4cp00090k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Al3+ derived from the (100) plane of γ-AlOOH at a relatively high H+ concentration can form well-defined basic aluminium sulfate microcrystals through a hydrothermal process.
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Affiliation(s)
- Yuguo Xia
- School of Chemistry & Chemical Engineering
- National Engineering Research Center for colloidal materials
- Shandong University
- Jinan 250100, P. R. China
| | - Bo Chen
- School of Chemistry & Chemical Engineering
- National Engineering Research Center for colloidal materials
- Shandong University
- Jinan 250100, P. R. China
| | - Xiuling Jiao
- School of Chemistry & Chemical Engineering
- National Engineering Research Center for colloidal materials
- Shandong University
- Jinan 250100, P. R. China
| | - Dairong Chen
- School of Chemistry & Chemical Engineering
- National Engineering Research Center for colloidal materials
- Shandong University
- Jinan 250100, P. R. China
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56
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Liu Z, Lv C. Fast synthesis of mesoporous γ-alumina assisted by a room temperature ionic liquid and its use as a support for the promotional catalytic performance of dibenzothiophene hydrodesulfurization. RSC Adv 2014. [DOI: 10.1039/c3ra45185b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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57
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58
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Jiao WQ, Liang XM, Wang YM, He MY. Formation of hierarchical boehmite with different nanostructures in dry-gel conversion process. CrystEngComm 2014. [DOI: 10.1039/c4ce00068d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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59
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You S, Li Y, Zhang Y, Yang C, Zhang Y. Synthesis of Uniformly Spherical Bayerite from a Sodium Aluminate Solution Reacted with Sodium Bicarbonate. Ind Eng Chem Res 2013. [DOI: 10.1021/ie401353t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shaowei You
- National Engineering
Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process
Engineering, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Li
- National Engineering
Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process
Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Yifei Zhang
- National Engineering
Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process
Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Chao Yang
- National Engineering
Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process
Engineering, Chinese Academy of Sciences, Beijing 100190, China
| | - Yi Zhang
- National Engineering
Laboratory for Hydrometallurgical Cleaner Production Technology, Key Laboratory of Green Process and Engineering, Institute of Process
Engineering, Chinese Academy of Sciences, Beijing 100190, China
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60
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Shefer KI, Cherepanova SV, Tsybulya SV, Isupov VP, Moroz ÈM. Effect of violations of the structure and layer packing on the diffraction pattern of gibbsite and bayerite. J STRUCT CHEM+ 2013. [DOI: 10.1134/s0022476613040112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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61
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Smith SJ, Amin S, Woodfield BF, Boerio-Goates J, Campbell BJ. Phase Progression of γ-Al2O3 Nanoparticles Synthesized in a Solvent-Deficient Environment. Inorg Chem 2013; 52:4411-23. [DOI: 10.1021/ic302593f] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Samrat Amin
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, United
States
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62
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Goesten MG, Stavitski E, Juan-Alcañiz J, Martiñez-Joaristi A, Petukhov AV, Kapteijn F, Gascon J. Small-angle X-ray scattering documents the growth of metal-organic frameworks. Catal Today 2013. [DOI: 10.1016/j.cattod.2012.08.044] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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63
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Duan X, Kim T, Li D, Ma J, Zheng W. Understanding the Effect Models of Ionic Liquids in the Synthesis of NH4-Dw and γ-AlOOH Nanostructures and Their Conversion into Porous γ-Al2O3. Chemistry 2013; 19:5924-37. [DOI: 10.1002/chem.201203176] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Indexed: 11/11/2022]
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64
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Playford HY, Hannon AC, Barney ER, Walton RI. Structures of Uncharacterised Polymorphs of Gallium Oxide from Total Neutron Diffraction. Chemistry 2013; 19:2803-13. [PMID: 23307528 DOI: 10.1002/chem.201203359] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Indexed: 11/12/2022]
Affiliation(s)
- Helen Y Playford
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
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65
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Lectez S, Roques J, Salanne M, Simoni E. Car-Parrinello molecular dynamics study of the uranyl behaviour at the gibbsite/water interface. J Chem Phys 2012; 137:154705. [DOI: 10.1063/1.4758935] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Sébastien Lectez
- Institut de Physique Nucléaire d'Orsay, Université Paris-Sud, CNRS UMR 8608, 15 rue Georges Clémenceau, Bâtiment 100, 91406 ORSAY Cedex, France
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66
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Effect of surface hydroxyls on DME and methanol adsorption over γ-Al2O3 (hkl) surfaces and solvent effects: a density functional theory study. J Mol Model 2012; 18:5107-11. [DOI: 10.1007/s00894-012-1495-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 06/05/2012] [Indexed: 10/28/2022]
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67
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Computing the Properties of Materials from First Principles with SIESTA. STRUCTURE AND BONDING 2012. [DOI: 10.1007/b97943] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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68
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Behafarid F, Ono LK, Mostafa S, Croy JR, Shafai G, Hong S, Rahman TS, Bare SR, Roldan Cuenya B. Electronic properties and charge transfer phenomena in Pt nanoparticles on γ-Al2O3: size, shape, support, and adsorbate effects. Phys Chem Chem Phys 2012; 14:11766-79. [DOI: 10.1039/c2cp41928a] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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69
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Zheng X, Zhang Y, Huang S, Liu H, Wang P, Tian H. Adsorption of thiophene on transition metal atoms (Co, Ni and Mo) modified Al20O30 clusters: DFT approaches. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2011.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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70
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Abstract
ABSTRACTThe controlled growth of alumina films by atomic layer deposition (ALD) is of great interest to the electronics industry, as high-k dielectrics are being sought for the next-generation of MOSFETS. We present a theoretical study of the alumina polymorph γ-Al2O3 based on density functional theory (DFT). The predicted bulk structure for γ-Al2O3 has the Al vacancy sites widely separated, which is in agreement with other theoretical predictions. We estimated the energy of several γ-Al2O3 surfaces namely: (111), (110) and (110). The atomic and electronic structure of the most stable (111) surface is discussed and compared with α-Al2O3 (0001). The adsorption and dissociation of the H2O onto the (111) surface is considered and H-diffusion is simulated. Finally, a model for the γ-Al2O3 (111)/aluminium-hydroxide interface is proposed and considered as an intermediate stage in the γ-alumina film growth mechanism.
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71
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Dabbagh HA, Zamani M, Davis BH. Nanoscale surface study and reactions mechanism of 2-butanol over the γ-alumina (100) surface and nanochannel: A DFT study. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.molcata.2010.09.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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72
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Kumara C, Ng W, Bandara A, Weerasooriya R. Nanogibbsite: Synthesis and characterization. J Colloid Interface Sci 2010; 352:252-8. [DOI: 10.1016/j.jcis.2010.08.083] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 08/29/2010] [Accepted: 08/31/2010] [Indexed: 12/01/2022]
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73
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Kinoshita K, Minami H, Tarutani Y, Okubo M. Preparation of Aluminum Hydroxide and Alumina Particles in an Ionic Liquid. CHEM LETT 2010. [DOI: 10.1246/cl.2010.741] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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74
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Bunker CE, Smith MJ, Fernando KAS, Harruff BA, Lewis WK, Gord JR, Guliants EA, Phelps DK. Spontaneous hydrogen generation from organic-capped Al nanoparticles and water. ACS APPLIED MATERIALS & INTERFACES 2010; 2:11-14. [PMID: 20356213 DOI: 10.1021/am900757r] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The development of technologies that would lead toward the adoption of a hydrogen economy requires readily available, safe, and environmentally friendly access to hydrogen. This can be achieved using the aluminum-water reaction; however, the protective nature and stability of aluminum oxide is a clear detriment to its application. Here, we demonstrate the spontaneous generation of hydrogen gas from ordinary room-temperature tap water when combined with aluminum-oleic acid core-shell nanoparticles obtained via sonochemistry. The reaction is found to be near-complete (>95% yield hydrogen) with a tunable rate from 6.4x10(-4) to 0.01 g of H2/s/g of Al and to yield an environmentally benign byproduct. The potential of these nanoparticles as a source of hydrogen gas for power generation is demonstrated using a simple fuel cell with an applied load.
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75
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Roques J, Veilly E, Simoni E. Periodic density functional theory investigation of the uranyl ion sorption on three mineral surfaces: a comparative study. Int J Mol Sci 2009; 10:2633-2661. [PMID: 19582222 PMCID: PMC2705509 DOI: 10.3390/ijms10062633] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 05/25/2009] [Accepted: 06/01/2009] [Indexed: 11/16/2022] Open
Abstract
Canister integrity and radionuclides retention is of prime importance for assessing the long term safety of nuclear waste stored in engineered geologic depositories. A comparative investigation of the interaction of uranyl ion with three different mineral surfaces has thus been undertaken in order to point out the influence of surface composition on the adsorption mechanism(s). Periodic DFT calculations using plane waves basis sets with the GGA formalism were performed on the TiO(2)(110), Al(OH)(3)(001) and Ni(111) surfaces. This study has clearly shown that three parameters play an important role in the uranyl adsorption mechanism: the solvent (H(2)O) distribution at the interface, the nature of the adsorption site and finally, the surface atoms' protonation state.
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Affiliation(s)
- Jérôme Roques
- Author to whom correspondence should be addressed; E-Mail:
; Tel. +33-169156869; Fax: +33-169157150
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76
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Jodin-Caumon MC, Humbert B, Phambu N, Gaboriaud F. A vibrational study of the nature of hydroxyl groups chemical bonding in two aluminium hydroxides. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2009; 72:959-964. [PMID: 19167269 DOI: 10.1016/j.saa.2008.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Revised: 12/08/2008] [Accepted: 12/08/2008] [Indexed: 05/27/2023]
Abstract
Lengths, strengths and valences of OH bonds in the two aluminium hydroxides gibbsite and bayerite were determined on the basis of vibrational spectral data. The uncoupled OD stretching modes in the range 2400-2800cm(-1) were recorded by means of infrared diffuse reflectance, thereby avoiding effects of surface, vibrational coupling or particle shape. The assignment of the corresponding Raman spectra resulted in the determination of harmonic wavenumbers, force constants and anharmonicity coefficients of bulk OH groups in the two minerals. OH bond lengths deduced from these data varied from 0.964A to 0.975A in gibbsite and 0.962A to 0.973A in bayerite. These lengths appear to correspond to weak H-bonds contrary to previously recognized data from X-ray diffraction and neutron diffraction studies. Finally, bond valences were calculated on the basis of these new bond lengths and discussed as a function of crystallographic structures and the nature of hydrogen bonding in these two structures.
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Affiliation(s)
- Marie-Camille Jodin-Caumon
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, UMR 7564 CNRS, Nancy-Université, 405 rue de Vandoeuvre, 54600 Villers-lès-Nancy, France.
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77
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Mitsui T, Matsui T, Kikuchi R, Eguchi K. Microstructural Transformation with Heat-Treatment of Aluminum Hydroxide with Gibbsite Structure. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2009. [DOI: 10.1246/bcsj.82.618] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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78
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Veilly E, Roques J, Jodin-Caumon MC, Humbert B, Drot R, Simoni E. Uranyl interaction with the hydrated (001) basal face of gibbsite: A combined theoretical and spectroscopic study. J Chem Phys 2008; 129:244704. [DOI: 10.1063/1.3042142] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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79
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Demichelis R, Civalleri B, Noel Y, Meyer A, Dovesi R. Structure and stability of aluminium trihydroxides bayerite and gibbsite: A quantum mechanical ab initio study with the Crystal06 code. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.09.070] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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80
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Demichelis R, Noel Y, Zicovich-Wilson CM, Roetti C, Valenzano L, Dovesi R. Ab-initioquantum mechanical study of akdalaite (5Al2O3· H2O): structure and vibrational spectrum. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/117/1/012013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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81
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Auxilio AR, Andrews PC, Junk PC, Spiccia L, Neumann D, Raverty W, Vanderhoek N, Pringle JM. Functionalised pseudo-boehmite nanoparticles as an excellent adsorbent material for anionic dyes. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b715545j] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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82
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Demichelis R, Noel Y, Civalleri B, Roetti C, Ferrero M, Dovesi R. The Vibrational Spectrum of α-AlOOH Diaspore: An Ab Initio Study with the CRYSTAL Code. J Phys Chem B 2007; 111:9337-46. [PMID: 17629324 DOI: 10.1021/jp072501d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The vibrational spectrum of alpha-AlOOH diaspore has been calculated at the B3LYP level of theory with a double-zeta quality Gaussian-type basis set by using the periodic ab initio CRYSTAL code. Harmonic frequencies at the Gamma point and the corresponding 48 normal modes are analyzed and classified in terms of simple models (octahedra modes, hydrogen stretching, bending, rotations) by direct inspection of eigenvectors, graphical representation, and isotopic substitution. Hydrogen modes are fully separated from the octahedra modes appearing under 800 cm(-1); bending modes are located in the range of 1040-1290 cm(-1), whereas stretching modes appear at 3130-3170 cm(-1). The available experimental IR and Raman spectra are characterized by broad bands, in some cases as large as 800 cm(-1), and individual peaks are obtained by decomposing these bands in terms of Lorentz-Gauss product functions; such a fitting procedure is affected by a relatively large degree of arbitrariness. The comparison of our calculated data with the most complete sets of experimental data shows, nevertheless, a relatively good agreement for all but the H modes; the mean absolute differences for modes not involving H are 10.9 and 7.2 cm(-1) for the IR and the Raman spectra, respectively, the maximum differences being 15.5 and 18.2 cm(-1). For the H bending modes, differences increase to 30 and 37 cm(-1), and for the stretching modes, the calculated frequencies are about 200 cm(-1) higher than the experimental ones; this is not surprising, as anharmonicity is expected to red shift the OH stretching by about 150 cm(-1) in isolated OH groups and even more when the latter is involved in strong hydrogen bonds, as is the case here.
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Affiliation(s)
- R Demichelis
- Dipartimento di Chimica IFM, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy
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83
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Joubert J, Delbecq F, Thieuleux C, Taoufik M, Blanc F, Copéret C, Thivolle-Cazat J, Basset JM, Sautet P. Synthesis, Characterization, and Catalytic Properties of γ-Al2O3-Supported Zirconium Hydrides through a Combined Use of Surface Organometallic Chemistry and Periodic Calculations. Organometallics 2007. [DOI: 10.1021/om070145f] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jérôme Joubert
- Laboratoire de Chimie, Institut de Chimie de Lyon, Université de Lyon, École Normale Supérieure de Lyon and CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France, and C2P2, Laboratoire de Chimie Organométallique de Surface (UMR 5265: CNRS-ESCPE Lyon), ESCPE Lyon, F-308, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne Cedex, France
| | - Françoise Delbecq
- Laboratoire de Chimie, Institut de Chimie de Lyon, Université de Lyon, École Normale Supérieure de Lyon and CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France, and C2P2, Laboratoire de Chimie Organométallique de Surface (UMR 5265: CNRS-ESCPE Lyon), ESCPE Lyon, F-308, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne Cedex, France
| | - Chloé Thieuleux
- Laboratoire de Chimie, Institut de Chimie de Lyon, Université de Lyon, École Normale Supérieure de Lyon and CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France, and C2P2, Laboratoire de Chimie Organométallique de Surface (UMR 5265: CNRS-ESCPE Lyon), ESCPE Lyon, F-308, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne Cedex, France
| | - Mostafa Taoufik
- Laboratoire de Chimie, Institut de Chimie de Lyon, Université de Lyon, École Normale Supérieure de Lyon and CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France, and C2P2, Laboratoire de Chimie Organométallique de Surface (UMR 5265: CNRS-ESCPE Lyon), ESCPE Lyon, F-308, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne Cedex, France
| | - Frédéric Blanc
- Laboratoire de Chimie, Institut de Chimie de Lyon, Université de Lyon, École Normale Supérieure de Lyon and CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France, and C2P2, Laboratoire de Chimie Organométallique de Surface (UMR 5265: CNRS-ESCPE Lyon), ESCPE Lyon, F-308, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne Cedex, France
| | - Christophe Copéret
- Laboratoire de Chimie, Institut de Chimie de Lyon, Université de Lyon, École Normale Supérieure de Lyon and CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France, and C2P2, Laboratoire de Chimie Organométallique de Surface (UMR 5265: CNRS-ESCPE Lyon), ESCPE Lyon, F-308, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne Cedex, France
| | - Jean Thivolle-Cazat
- Laboratoire de Chimie, Institut de Chimie de Lyon, Université de Lyon, École Normale Supérieure de Lyon and CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France, and C2P2, Laboratoire de Chimie Organométallique de Surface (UMR 5265: CNRS-ESCPE Lyon), ESCPE Lyon, F-308, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne Cedex, France
| | - Jean-Marie Basset
- Laboratoire de Chimie, Institut de Chimie de Lyon, Université de Lyon, École Normale Supérieure de Lyon and CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France, and C2P2, Laboratoire de Chimie Organométallique de Surface (UMR 5265: CNRS-ESCPE Lyon), ESCPE Lyon, F-308, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne Cedex, France
| | - Philippe Sautet
- Laboratoire de Chimie, Institut de Chimie de Lyon, Université de Lyon, École Normale Supérieure de Lyon and CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France, and C2P2, Laboratoire de Chimie Organométallique de Surface (UMR 5265: CNRS-ESCPE Lyon), ESCPE Lyon, F-308, 43 Boulevard du 11 Novembre 1918, 69616 Villeurbanne Cedex, France
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84
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Carrier X, Marceau E, Lambert JF, Che M. Transformations of γ-alumina in aqueous suspensions. J Colloid Interface Sci 2007; 308:429-37. [PMID: 17286982 DOI: 10.1016/j.jcis.2006.12.074] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 12/21/2006] [Accepted: 12/30/2006] [Indexed: 10/23/2022]
Abstract
Hydration of gamma-Al2O3 is often reported to occur via the superficial transformation of the alumina surface into aluminum hydroxide-like layers. However, very little evidence has been given so far to support this hypothesis. It is demonstrated here by X-ray diffraction, TEM, electron diffraction, and solubility studies that a second process of hydration takes place that involves the dissolution of alumina and subsequent precipitation of well-shaped Al(OH)3 particles from supersaturated alumina aqueous solution. This process can be observed on a macroscopic scale (XRD, TEM) for any pH5, provided that the contact time between alumina and water exceeds 10 h. The least thermodynamically stable phase of aluminum hydroxide, bayerite, becomes favored compared with gibbsite when the pH of the solution is increased. It is assumed that the rate of formation of bayerite germs is greater than that of gibbsite due to variations in aluminum speciation in solution as a function of pH.
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Affiliation(s)
- Xavier Carrier
- Laboratoire de Réactivité de Surface (UMR 7609-CNRS), Université Pierre & Marie Curie-Paris 6, 4 place Jussieu, 75252 Paris Cedex 05, France.
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85
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Copéret C. Design and understanding of heterogeneous alkene metathesis catalysts. Dalton Trans 2007:5498-504. [DOI: 10.1039/b713314f] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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86
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Marqués M, Flórez M, Recio JM, Santamaría D, Vegas A, García Baonza V. Structure, metastability, and electron density of Al lattices in light of the model of anions in metallic matrices. J Phys Chem B 2006; 110:18609-18. [PMID: 16970490 DOI: 10.1021/jp063883a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper reports a theoretical investigation of the structure, stability, and electron charge density of cubic, rhombohedral, hexagonal, and monoclinic Al lattices. The equations of state and the elastic constants are computed from total energy calculations at different volumes and unit cell strains using the density functional theory approximation. The topology of the electron density is analyzed within the crystalline implementation of the atoms in molecules formalism. The results are discussed in light of the so-called anions in metallic matrices model, which permits the interpretation of the chemical bonding and the explanation of the existence of particular symmetries of inorganic crystals. First, the Al sublattices are identified as the reference building blocks of AlX(3) (X = F, Cl, OH) compounds. The calculations reveal that the equilibrium zero-pressure Al-Al shortest distance is around 2.75 A in all of the Al matrixes, similar to the value observed in the stable face centered cubic structure of Al at room conditions. Second, at their zero-pressure equilibrium geometries, the Al sublattices are found to fulfill the mechanical stability criteria or, alternatively, to show mechanical instabilities that are compatible with the distortions observed for the structures in AlX(3) crystals. However, at the equilibrium volumes of the AlX(3) crystals, all of the Al matrices violate the spinodal condition, and the cohesion and stabilization are provided by the nonmetallic X atoms. Third, the structural anisotropy of the Al sublattices seems to be the main factor to discriminate metallic matrices able to host nonmetallic elements. The inhomogeneities of the electron charge density, which favor the arrival of nonmetallic elements and the crystal formation, are notably enhanced in passing from the fcc structure of pure Al to the less isotropic Al matrices observed in AlX(3) compounds.
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Affiliation(s)
- M Marqués
- Departamento de Química Física y Analítica, Universidad de Oviedo, E-33006 Oviedo, Spain
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87
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Joubert J, Delbecq F, Sautet P, Le Roux E, Taoufik M, Thieuleux C, Blanc F, Copéret C, Thivolle-Cazat J, Basset JM. Molecular Understanding of Alumina Supported Single-Site Catalysts by a Combination of Experiment and Theory. J Am Chem Soc 2006; 128:9157-69. [PMID: 16834389 DOI: 10.1021/ja0616736] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The nature and structure of grafted organometallic complexes on gamma-alumina are studied from a combination of experimental data (mass balance analysis, IR, NMR) and density functional theory calculations. The chemisorptive interactions of two complexes are analyzed and compared. The reaction of [Zr(CH2tBu)4] with alumina dehydroxylated at 500 degrees C gives {[(AlsO)2Zr(CH2tBu)]+[(tBuCH2)(Als)]-}, a bisgrafted cationic complex as major surface species. The DFT calculations show that the reaction with surface hydroxyls is very exothermic and that alkyl transfer on Al atoms is favored. In contrast, [W(CtBu)(CH2tBu)3] reacts with an alumina treated under identical conditions to give selectively a monografted neutral surface complex, [(AlsO)W(CtBu)(CH2tBu)2]. This was inferred by the evolution of 1 equiv of tBuCH3 per grafted W and the presence of remaining hydroxyls. The calculations show that the reaction of [W(CtBu)(CH2tBu)3] with surface hydroxyls is in fact less exothermic and has a considerably higher activation barrier than the one of the Zr complex. Additionally, the transfer of an alkyl ligand onto an adjacent Al center is disfavored, and hence cationic species are not formed. Some ligands of this monoaluminoxy surface complex interact with remaining surface hydroxyls, which explains the complexity of the experimental NMR and IR data.
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Affiliation(s)
- Jérôme Joubert
- Laboratoire de Chimie (UMR 5182 CNRS/ENS), Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
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88
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Bucko T, Hafner J, Angyán JG. Geometry optimization of periodic systems using internal coordinates. J Chem Phys 2006; 122:124508. [PMID: 15836398 DOI: 10.1063/1.1864932] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An algorithm is proposed for the structural optimization of periodic systems in internal (chemical) coordinates. Internal coordinates may include in addition to the usual bond lengths, bond angles, out-of-plane and dihedral angles, various "lattice internal coordinates" such as cell edge lengths, cell angles, cell volume, etc. The coordinate transformations between Cartesian (or fractional) and internal coordinates are performed by a generalized Wilson B-matrix, which in contrast to the previous formulation by Kudin et al. [J. Chem. Phys. 114, 2919 (2001)] includes the explicit dependence of the lattice parameters on the positions of all unit cell atoms. The performance of the method, including constrained optimizations, is demonstrated on several examples, such as layered and microporous materials (gibbsite and chabazite) as well as the urea molecular crystal. The calculations used energies and forces from the ab initio density functional theory plane wave method in the projector-augmented wave formalism.
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Affiliation(s)
- Tomás Bucko
- Computational Materials Science, Institut für Materialphysik, Universität Wien, Sensengasse 8/12, A-1090 Wien, Austria.
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89
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Stößer R, Nofz M, Feist M, Scholz G. Fe3+-assisted formation of α-Al2O3, starting from sol–gel precursors. J SOLID STATE CHEM 2006. [DOI: 10.1016/j.jssc.2005.11.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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90
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Hino M, Matsuhashi H, Arata K. Synthesis of a Ceramic Acid of Tungstated Alumina more Active than Silica-alumina for Decompositions of Cumene, Ethylbenzene, and Toluene. Catal Letters 2006. [DOI: 10.1007/s10562-005-0012-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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91
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Taniike T, Tada M, Morikawa Y, Sasaki T, Iwasawa Y. Density Functional Theoretical Calculations for a Co2/γ-Al2O3 Model Catalyst: Structures of the γ-Al2O3 Bulk and Surface and Attachment Sites for Co2+ Ions. J Phys Chem B 2006; 110:4929-36. [PMID: 16526733 DOI: 10.1021/jp057341p] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
First-principle density functional theory (DFT) calculations on the electronic state and structure of a [Co2+]2/gamma-Al2O3 model catalyst have been performed in relation to catalysis for unique NO-CO reactions on a Co2+ ensemble/gamma-Al2O3 catalyst. The DFT calculations reveal that a bulk structure of gamma-Al2O3 is energetically most favorable when aluminum vacancies are evenly dispersed at octahedral sites, and that the (110) plane is exposed as a top-most layer by its neutrality. Two Co2+ ions on the (110) surface are supported adjacently to each other in a tetrahedral symmetry. The calculations also demonstrate that the vacant d orbitals of the two Co2+ ions are directed toward each other, which brings about an adsorbate-adsorbate interaction between two molecules which adsorb on each of the Co2+ ions. This may be an origin of the unique aspect of Co2+ ensemble/gamma-Al2O3 catalysis.
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Affiliation(s)
- Toshiaki Taniike
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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92
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Frenzel J, Oliveira AF, Duarte HA, Heine T, Seifert G. Structural and Electronic Properties of Bulk Gibbsite and Gibbsite Surfaces. Z Anorg Allg Chem 2005. [DOI: 10.1002/zaac.200500051] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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93
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Liu H, Tse JS, Hu J, Liu Z, Wang L, Chen J, Weidner DJ, Meng Y, Häusermann D, Mao HK. Structural Refinement of the High-Pressure Phase of Aluminum Trihydroxide: In-Situ High-Pressure Angle Dispersive Synchrotron X-ray Diffraction and Theoretical Studies. J Phys Chem B 2005; 109:8857-60. [PMID: 16852053 DOI: 10.1021/jp0501594] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In-situ high-pressure synchrotron angle-dispersive X-ray diffraction for gibbsite (aluminum trihydroxide) was performed at room temperature up to 20 GPa. A pressure-induced phase transition was observed at 2.6 GPa. The new high-pressure phase can be recovered at ambient pressure. Rietveld refinement shows that the new phase of Al(OH)(3) has an orthorhombic structure, spacegroup Pbca, and the lattice parameters at ambient condition are a = 868.57(5) pm, b = 505.21(4) pm, c = 949.54(6) pm, V = 416.67(6) x 10(6) pm(3) with Z = 8. The compressibility of gibbsite and the high-pressure polymorph was analyzed, and their bulk moduli were estimated as 49.8 +/- 1.8 and 81.0 +/- 5.2 GPa, respectively. First-principles calculations of the high-pressure phase were performed to determine the hydrogen positions and to confirm the structural stability of the new phase.
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Affiliation(s)
- Haozhe Liu
- HPCAT, Advanced Photon Source, Building 434E, Argonne National Laboratory, Argonne, Illinois 60439-4803, USA.
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94
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95
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Nguefack M, Popa AF, Rossignol S, Kappenstein C. Preparation of alumina through a sol–gel process. Synthesis, characterization, thermal evolution and model of intermediate boehmite. Phys Chem Chem Phys 2003. [DOI: 10.1039/b306170a] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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96
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Watanabe H, Kitamura T, Hoshino K. Preparation and Characterization of Composite Films of Polypyrrole with Metal Oxide /Hydroxides Using Galvanic Corrosion Reaction. ACTA ACUST UNITED AC 2003. [DOI: 10.1149/1.1566536] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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