Spatially Resolved Imaging of Inhomogeneous Charge Transfer Behavior in Polymorphous Molybdenum Oxide. I. Correlation of Localized Structural, Electronic, and Chemical Properties Using Conductive Probe Atomic Force Microscopy and Raman Microprobe Spectroscopy

McEvoy, Todd M.; Stevenson, Keith J.

doi:10.1021/la047276v

Cited by 45 publications

(44 citation statements)

References 34 publications

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“…The Raman spectra of PMA‐(C) differ from the spectra of the pure bulk PMA and the band at

\overset{ν}{true}

=815 cm −1 becomes the most intensive (Figure ). The observed bands position at

\overset{ν}{true}

=990, 815, and 661 cm −1 and intensity ratio are very close to the Raman spectra of orthorombic molybdenum oxide—α‐MoO 3 observed earlier with maxima at

\overset{ν}{true}

=995, 820, and 666 cm −1 . From the technological point of view, the use of PMA‐(B) was inconvenient due to unequal spreading of PMA‐(B) on the glass walls of the flask, and difficulties with its regeneration.…”

Section: Resultssupporting

confidence: 91%

Catalyst Development for the Synthesis of Ozonides and Tetraoxanes Under Heterogeneous Conditions: Disclosure of an Unprecedented Class of Fungicides for Agricultural Application

Yaremenko

Radulov

Belyakova

et al. 2020

Chemistry A European J

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The catalyst H3+xPMo12−x+6Mox+5O40 supported on SiO2 was developed for peroxidation of 1,3‐ and 1,5‐diketones with hydrogen peroxide with the formation of bridged 1,2,4,5‐tetraoxanes and bridged 1,2,4‐trioxolanes (ozonides) with high yield based on isolated products (up to 86 and 90 %, respectively) under heterogeneous conditions. Synthesis of peroxides under heterogeneous conditions is a rare process and represents a challenge for this field of chemistry, because peroxides tend to decompose on the surface of a catalyst . A new class of antifungal agents for crop protection, that is, cyclic peroxides: bridged 1,2,4,5‐tetraoxanes and bridged ozonides, was discovered. Some ozonides and tetraoxanes exhibit a very high antifungal activity and are superior to commercial fungicides, such as Triadimefon and Kresoxim‐methyl. It is important to note that none of the fungicides used in agricultural chemistry contains a peroxide fragment.

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“…The Raman spectra of PMA‐(C) differ from the spectra of the pure bulk PMA and the band at

\overset{ν}{true}

=815 cm −1 becomes the most intensive (Figure ). The observed bands position at

\overset{ν}{true}

=990, 815, and 661 cm −1 and intensity ratio are very close to the Raman spectra of orthorombic molybdenum oxide—α‐MoO 3 observed earlier with maxima at

\overset{ν}{true}

Section: Resultssupporting

confidence: 91%

Catalyst Development for the Synthesis of Ozonides and Tetraoxanes Under Heterogeneous Conditions: Disclosure of an Unprecedented Class of Fungicides for Agricultural Application

Yaremenko

Radulov

Belyakova

et al. 2020

Chemistry A European J

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“…1 [48], as confirmed by XRD and electron diffraction (not shown). Figure 2 depicts spectra of dehydrated Mo x O y /SBA-15 samples at 500°C in dry flowing air.…”

Section: Resultsmentioning

confidence: 61%

Structure of molybdenum oxide supported on silica SBA-15 studied by Raman, UV–Vis and X-ray absorption spectroscopy

Thielemann

Ressler

Walter

et al. 2011

Applied Catalysis A: General

102

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The structure of molybdenum oxide supported by silica SBA-15 has been studied by visible Raman spectroscopy, diffuse reflectance UV-Vis spectroscopy and X-ray absorption spectroscopy in the dehydrated state obtained after thermal treatment at elevated temperatures (≥350°C). No dependence of the molybdenum oxide structure on preparation procedure or loading has been observed within the range of loadings studied in detail (0.2 to 0.8 Mo/nm 2 ). X-ray absorption spectroscopy (XAS) reveals that the dehydrated state consists of a mixture of monomeric and connected molybdenum oxide centres. While the presence of crystalline MoO3 can be excluded by Raman spectroscopy, tetrahedrally and octahedrally coordinated MoO4 and MoO6 units are identified by XAS. The MoO6 units possess connectivity similar to that of MoO3 building blocks, whereas the MoO4 units are isolated or connected to other MoxOy units. These results are supported by UV-Vis spectra showing intensity at wavelengths (>300 nm) typical for dimeric and/or oligomeric species.

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“…3b. Intense lines at 120 cm -1 and 135 cm -1 are assigned to deformations of rigidly bound chains of the octahedra [27][28][29][30]. The spectral line at 177 cm -1 is assigned to the twisting vibrations of the О=Мо=О bonds [27,31,32].…”

Section: Resultsmentioning

confidence: 99%

“…Intense lines at 120 cm -1 and 135 cm -1 are assigned to deformations of rigidly bound chains of the octahedra [27][28][29][30]. The spectral line at 177 cm -1 is assigned to the twisting vibrations of the О=Мо=О bonds [27,31,32]. Intense lines at 219 cm -1 and 250 cm -1 are assigned to bending vibrational modes of the О-Мо-О bond [2,28,[32][33][34].…”

Section: Resultsmentioning

confidence: 99%

Thermal transformations of the composition and structure of hexagonal molybdenum oxide

et al. 2015

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Thermal transformations of the crystal structure and composition of the h-MoO 3 metastable phase with a transition to the α-МоО 3 stable modification are investigated. The study is performed using submicron phase-pure crystals exhibiting stability during their long storage in the air. By powder XRD, SEM, TGA, CHN, LMS, Raman and IR spectroscopy it is found: the composition of the deposited crystals is expressed by the general formula МоО 3 ⋅0.26H 2 O; the impurity cationic composition consists of 1.8 wt.% of ammonia groups and a sum of 15 elements detected at a level of 10 -4 wt.%. Thermal treatment of the crystals to T = 350 °C in the air results in the removal of adsorbed and structural water, ОН -, and 4 NH + groups with retaining the h-phase of hygroscopic МоО 3 ⋅0.08H 2 O. The h-МоО 3 ⋅0.08H 2 O crystals obtained show instability during the storage and transform into the α-МоО 3 stable modification. At T = 380 °C the h → α phase transition occurs with the removal of coordinated water and texture transformations resulting in the formation of α-МоО 3 hygroscopic crystals that at T = 650 °C acquire the platelet shape characteristic of the α-phase.

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Spatially Resolved Imaging of Inhomogeneous Charge Transfer Behavior in Polymorphous Molybdenum Oxide. I. Correlation of Localized Structural, Electronic, and Chemical Properties Using Conductive Probe Atomic Force Microscopy and Raman Microprobe Spectroscopy

Cited by 45 publications

References 34 publications

Catalyst Development for the Synthesis of Ozonides and Tetraoxanes Under Heterogeneous Conditions: Disclosure of an Unprecedented Class of Fungicides for Agricultural Application

Catalyst Development for the Synthesis of Ozonides and Tetraoxanes Under Heterogeneous Conditions: Disclosure of an Unprecedented Class of Fungicides for Agricultural Application

Structure of molybdenum oxide supported on silica SBA-15 studied by Raman, UV–Vis and X-ray absorption spectroscopy

Thermal transformations of the composition and structure of hexagonal molybdenum oxide

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