Molybdenum Trioxide on Anatase TiO2(101) - Formation of Monodispersed (MoO3)1 Monomers from Oligomeric (MoO3)n Clusters

2020 ◽  
Author(s):  
Nassar Doudin ◽  
Gregory Collinge ◽  
Pradeep Kumar Gurunathan ◽  
Mal Soon Lee ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Molybdenum Trioxide ◽  
Theoretical Calculations ◽  
Complex Oxide ◽  
Oxide Systems ◽  
Design And Synthesis ◽  
Saturation Coverage ◽  
Resolution Imaging ◽  
Complete Layer ◽  
Immense Potential ◽  
Ordered Layers

<p>Complex oxide systems with hierarchical order are of critical importance in material science and catalysis. Despite their immense potential, their design and synthesis are rather difficult. In this study we demonstrate how the deposition of small oligomeric (MoO<sub>3</sub>)<sub>1-6</sub> clusters, which can be formed by the sublimation of MoO<sub>3</sub> powders, leads to the formation of locally ordered layers of (MoO<sub>3</sub>)<sub>1</sub> monomers on anatase TiO<sub>2</sub>(101). Using both high-resolution imaging and theoretical calculations, we show that at room temperature, such oligomers undergo spontaneous dissociation to their monomeric units. In initial stages of the deposition, this is reflected by the observation of one to six neighboring (MoO<sub>3</sub>)<sub>1</sub> monomers that parallel the size distribution of the oligomers. A transient mobility of such oligomers on both bare TiO<sub>2</sub>(101) and (MoO<sub>3</sub>)<sub>1</sub> covered areas is key to the formation of a complete layer with a saturation coverage of one (MoO<sub>3</sub>)<sub>1</sub> per two undercoordinated surface Ti sites. We further show that such layers are stable to 500 K, making them highly suitable for a broad range of applications. </p>

scholarly journals Molybdenum Trioxide on Anatase TiO2(101) - Formation of Monodispersed (MoO3)1 Monomers from Oligomeric (MoO3)n Clusters

2020 ◽  
Author(s):  
Nassar Doudin ◽  
Gregory Collinge ◽  
Pradeep Kumar Gurunathan ◽  
Mal Soon Lee ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Molybdenum Trioxide ◽  
Theoretical Calculations ◽  
Complex Oxide ◽  
Oxide Systems ◽  
Design And Synthesis ◽  
Saturation Coverage ◽  
Resolution Imaging ◽  
Complete Layer ◽  
Immense Potential ◽  
Ordered Layers

<p>Complex oxide systems with hierarchical order are of critical importance in material science and catalysis. Despite their immense potential, their design and synthesis are rather difficult. In this study we demonstrate how the deposition of small oligomeric (MoO<sub>3</sub>)<sub>1-6</sub> clusters, which can be formed by the sublimation of MoO<sub>3</sub> powders, leads to the formation of locally ordered layers of (MoO<sub>3</sub>)<sub>1</sub> monomers on anatase TiO<sub>2</sub>(101). Using both high-resolution imaging and theoretical calculations, we show that at room temperature, such oligomers undergo spontaneous dissociation to their monomeric units. In initial stages of the deposition, this is reflected by the observation of one to six neighboring (MoO<sub>3</sub>)<sub>1</sub> monomers that parallel the size distribution of the oligomers. A transient mobility of such oligomers on both bare TiO<sub>2</sub>(101) and (MoO<sub>3</sub>)<sub>1</sub> covered areas is key to the formation of a complete layer with a saturation coverage of one (MoO<sub>3</sub>)<sub>1</sub> per two undercoordinated surface Ti sites. We further show that such layers are stable to 500 K, making them highly suitable for a broad range of applications. </p>

scholarly journals Molybdenum Trioxide on Anatase TiO2(101) - Formation of Monodispersed (MoO3)1 Monomers from Oligomeric (MoO3)n Clusters

2020 ◽  
Author(s):  
Nassar Doudin ◽  
Gregory Collinge ◽  
Pradeep Kumar Gurunathan ◽  
Mal Soon Lee ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Molybdenum Trioxide ◽  
Theoretical Calculations ◽  
Complex Oxide ◽  
Oxide Systems ◽  
Design And Synthesis ◽  
Saturation Coverage ◽  
Resolution Imaging ◽  
Complete Layer ◽  
Immense Potential ◽  
Ordered Layers

<p>Complex oxide systems with hierarchical order are of critical importance in material science and catalysis. Despite their immense potential, their design and synthesis are rather difficult. In this study we demonstrate how the deposition of small oligomeric (MoO<sub>3</sub>)<sub>1-6</sub> clusters, which can be formed by the sublimation of MoO<sub>3</sub> powders, leads to the formation of locally ordered layers of (MoO<sub>3</sub>)<sub>1</sub> monomers on anatase TiO<sub>2</sub>(101). Using both high-resolution imaging and theoretical calculations, we show that at room temperature, such oligomers undergo spontaneous dissociation to their monomeric units. In initial stages of the deposition, this is reflected by the observation of one to six neighboring (MoO<sub>3</sub>)<sub>1</sub> monomers that parallel the size distribution of the oligomers. A transient mobility of such oligomers on both bare TiO<sub>2</sub>(101) and (MoO<sub>3</sub>)<sub>1</sub> covered areas is key to the formation of a complete layer with a saturation coverage of one (MoO<sub>3</sub>)<sub>1</sub> per two undercoordinated surface Ti sites. We further show that such layers are stable to 500 K, making them highly suitable for a broad range of applications. </p>

scholarly journals Creating self-assembled arrays of mono-oxo (MoO3)1 species on TiO2(101) via deposition and decomposition of (MoO3)n oligomers

2021 ◽  
Vol 118 (4) ◽  
pp. e2017703118
Author(s):  
Nassar Doudin ◽  
Greg Collinge ◽  
Pradeep Kumar Gurunathan ◽  
Mal-Soon Lee ◽  
Vassiliki-Alexandra Glezakou ◽  
...  
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Surface Acting ◽  
Dynamic Coupling ◽  
Design And Synthesis ◽  
Ordered Arrays ◽  
Defect Sites ◽  
Saturation Coverage ◽  
Resolution Imaging

Hierarchically ordered oxides are of critical importance in material science and catalysis. Unfortunately, the design and synthesis of such systems remains a key challenge to realizing their potential. In this study, we demonstrate how the deposition of small oligomeric (MoO3)1–6 clusters—formed by the facile sublimation of MoO3 powders—leads to the self-assembly of locally ordered arrays of immobilized mono-oxo (MoO3)1 species on anatase TiO2(101). Using both high-resolution imaging and theoretical calculations, we reveal the dynamic behavior of the oligomers as they spontaneously decompose at room temperature, with the TiO2 surface acting as a template for the growth of this hierarchically structured oxide. Transient mobility of the oligomers on both bare and (MoO3)1-covered TiO2(101) areas is identified as key to the formation of a complete (MoO3)1 overlayer with a saturation coverage of one (MoO3)1 per two undercoordinated surface Ti sites. Simulations reveal a dynamic coupling of the reaction steps to the TiO2 lattice fluctuations, the absence of which kinetically prevents decomposition. Further experimental and theoretical characterizations demonstrate that (MoO3)1 within this material are thermally stable up to 500 K and remain chemically identical with a single empty gap state produced within the TiO2 band structure. Finally, we see that the constituent (MoO3)1 of this material show no proclivity for step and defect sites, suggesting they can reliably be grown on the (101) facet of TiO2 nanoparticles without compromising their chemistry.

Synthesis of YFeO3-δ and LaFeO3-δ Perovskites with High Catalytic Activity in Carbon Oxidation Reactions

2021 ◽  
Vol 316 ◽  
pp. 105-109
Author(s):  
Evgeny A. Kirichenko ◽  
Pavel G. Chigrin ◽  
Anton A. Gnidenko
Keyword(s):  
Oxidation Mechanism ◽  
Soot Oxidation ◽  
Complex Oxide ◽  
Maximum Temperature ◽  
High Catalytic Activity ◽  
Carbon Oxidation ◽  
Oxidation Reactions ◽  
Oxide Systems ◽  
Reduction Of Metal Oxides ◽  
Catalytic Reaction Mechanism

YFeO3-δ (δ = 0.26) and LaFeO3-δ (δ = 0.5) perovskites with a high specific surface and oxygen non-stoichiometry was firstly synthesized by pyrolysis of polymer-salt compositions. It was shown that the catalytic oxidation of carbon in the presence of these complex oxide systems proceeds in the range of 400 - 700 °С, with a maximum temperature at 556 °С for YFeO3-δ; and 380 - 620 °С ,with a maximum temperature at 501 °С for LaFeO3-δ, in one-stage mode for both. By means of thermal analysis and diffractometry, it was shown that there is no contribution to the soot oxidation mechanism by cyclic perovskite surface transformations, due to the reduction of metal oxides by the soot and their subsequent reoxidation. It has been established that the basis of the catalytic reaction mechanism for both perovskites is the presence of oxygen vacancies on the surface of complex oxides.

Design and synthesis ofN1,N8-diacetylspermidine analogues having a linker with desired functional groups

2019 ◽  
Vol 17 (4) ◽  
pp. 867-875
Author(s):  
Reiya Ohta ◽  
Akihiro Oguro ◽  
Kazuhiro Nishimura ◽  
Kenichi Murai ◽  
Hiromichi Fujioka ◽  
...  
Keyword(s):  
Functional Groups ◽  
Theoretical Calculations ◽  
Design And Synthesis

The synthesis of newN1,N8-diacetylspermidine (DiAcSpd) analogues having a linker with desired functional groups in the methylene skeleton, which have been designed by theoretical calculations, is described.

A Study of Evaporation of Complex Oxide Systems Based on Chromium(III) Oxide

2003 ◽  
Vol 76 (10) ◽  
pp. 1564-1567 ◽  
Author(s):  
V. A. Popov ◽  
S. I. Lopatin ◽  
L. Sh. Tsemekhman ◽  
L. A. Pavlinova ◽  
S. P. Kormilitsyn ◽  
...  
Keyword(s):  
Complex Oxide ◽  
Oxide Systems

Multilayered Structures of SrNb0.1Ti0.9O3/La0.8Sr0.2MnO3/SrTiO3 Prepared by Laser Molecular Beam Epitaxy

2002 ◽  
Vol 17 (3) ◽  
pp. 600-608
Author(s):  
X. L. Ma ◽  
H. B. Lu ◽  
F. Chen ◽  
Z. H. Chen ◽  
G. Z. Yang
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Theoretical Calculations ◽  
Geometrical Model ◽  
Charge Ordering ◽  
Multilayered Structures ◽  
Laser Molecular Beam Epitaxy ◽  
Transmission Electron ◽  
Orthorhombic Cell ◽  
Resolution Imaging

Multilayer oxides of SrNb0.1Ti0.9O3/La0.8Sr0.2MnO3/SrTiO3 have been grown by computer-controlled laser molecular beam epitaxy and characterized by transmission electron microscopy. Electron microdiffractions and high-resolution imaging reveal that the as-prepared thin film of La0.8Sr0.2MnO3 with thickness of 200 nm is epitaxially grown on the SrTiO3(001) substrate and the SrNb0.1Ti0.9O3 with thickness of 250 nm epitaxially on the as-received La0.8Sr0.2MnO3 film. The microstructures in the La0.8Sr0.2MnO3 film are clarified in terms of the oriented microdomains. In contrast, microstructures in SNTO are featured by the formation of superstructures due to charge ordering. Crystallographic relationships of these domains are discussed on the basis of an orthorhombic cell and rationalized by theoretical calculations based on a geometrical model.

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