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Novel synthetic routes to organosilicon speciesYeh, Li-Tain January 1991 (has links)
No description available.
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Novel Synthetic And Mechanistic Studies In Oxime And Amide ChemistryGopalaiah, Kovuru 05 1900 (has links) (PDF)
No description available.
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Photocatalysis studies using mesoporous modified V-MCM-48 Stober synthesis: acetaldehyde, carbon monoxide, ethanol, acetone, 2-propanol, & acetonitrileMahoney, Luther James January 1900 (has links)
Master of Science / Department of Chemistry / Kenneth J. Klabunde / Although Degussia-Huls P-25 TiO[subscript]2 semiconductor photocatalyst has high photodegradation rate for organic molecules, it works only under ultra-violet (UV) light. Mesoporous metal doped V-MCM-48 silica was synthesized under ambient conditions for use as a visible-light photocatalyst to convert toxic probe molecules to innocuous products: CO[subscript]2 + H[subscript]2O. The synthesis employed a modified Stober metal doped MCM-48 silica method. Powder X-ray diffraction (XRD), diffuse-reflectance-ultra-violet-visible (DR-UV-vis) spectroscopy, and N[subscript]2 adsorption-desorpton analysis characterization methods were completed on V-MCM-48 mesoporous material. These characterization methods indicate V-MCM-48 structure had formed with visible light absorption and mesoporous properties. Photocatalysis studies were completed with V-MCM-48 under dark, visible, and UV-light illumination conditions for the following probe molecules: acetaldehyde, carbon monoxide, ethanol, acetone, 2-propanol, and acetonitrile. Acetaldehyde over V-MCM-48 was converted to CO[subscript]2 under dark, visible, and UV-light conditions. Carbon monoxide photooxidation occurred over V-MCM-48 under visible and UV-light. Ethanol and acetonitrile had smaller photodegradation activity over V-MCM-48. Acetone and 2-propanol had no activity photocatalytically. Under dark and visible light illumination, V-MCM-48 consumed approximately one-half acetaldehyde and produced one-third CO[subscript]2 concentration as compared with the P-25 TiO[subscript]2 under UV-light. V-MCM-48 produced two-thirds of the amount of CO[subscript]2 in comparison to nanoparticle Au/ZnO catalyst under UV-light. The results infer V-MCM-48 might be useful in gas and liquid phase photocatalysis including water-splitting due to a high oxidation state (V[superscript]5+), visible light absorption, and high surface area. In conclusion, an extended literature review has been completed and literature employed extensively throughout the thesis with potential methods to further the research on V-MCM-48/Si-MCM-48 in catalysis, chromatography, adsorption/gas separation, and solar collection/water-splitting.
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Novel approaches to the synthesis and treatment of cathode materials for lithium-ion batteriesRodrigues, Isadora R. 07 1900 (has links)
Nous avons mis au point une approche novatrice pour la synthèse d’un
matériau de cathode pour les piles lithium-ion basée sur la décomposition
thermique de l’urée. Les hydroxydes de métal mixte (NixMnxCo(1-2x)(OH)2) ont
été préparés (x = 0.00 à 0.50) et subséquemment utilisés comme précurseurs à la
préparation de l’oxyde de métal mixte (LiNixMnxCo(1-2x)O2). Ces matériaux,
ainsi que le phosphate de fer lithié (LiFePO4), sont pressentis comme matériaux
de cathode commerciaux pour la prochaine génération de piles lithium-ion. Nous
avons également développé un nouveau traitement post-synthèse afin
d’améliorer la morphologie des hydroxydes.
L’originalité de l’approche basée sur la décomposition thermique de
l’urée réside dans l’utilisation inédite des hydroxydes comme précurseurs à la
préparation d’oxydes de lithium mixtes par l’intermédiaire d’une technique de
précipitation uniforme. De plus, nous proposons de nouvelles techniques de
traitement s’adressant aux méthodes de synthèses traditionnelles. Les résultats
obtenus par ces deux méthodes sont résumés dans deux articles soumis à des
revues scientifiques.
Tous les matériaux produits lors de cette recherche ont été analysés par
diffraction des rayons X (DRX), microscope électronique à balayage (MEB),
analyse thermique gravimétrique (ATG) et ont été caractérisés
électrochimiquement. La performance électrochimique (nombre de cycles vs
capacité) des matériaux de cathode a été conduite en mode galvanostatique. / We have developed a novel approach to the synthesis of cathode
materials for lithium-ion batteries, based on the thermal decomposition of urea.
Mixed metal hydroxides (NixMnxCo(1-2x)(OH)2), x = 0.00 to 0.50, were prepared
and subsequently used as precursor for lithiated mixed metal oxide
(LiNixMnxCo(1-2x)O2). These materials along with lithium iron phosphate
(LiFePO4) are being considered as cathode materials for the next generation of
lithium-ion batteries. We have also developed new post-synthetic treatments on
the hydroxides in order to enhance the morphology, which would result in
improved electrode properties.
The novelty of this thesis is that for the first time mixed metal
hydroxides for use as precursors for lithium mixed oxides have been prepared
via a uniform precipitation technique from solution. In addition, we have
proposed new treatments techniques towards the more traditional synthesis
method for mixed metal hydroxides. The results obtained from these two
methods are summarized within two articles that were recently submitted to
peer-reviewed journals.
Within this thesis, all materials were analyzed with X-ray diffraction
(XRD), scanning electron microscopy (SEM), thermal gravimetric analysis
(TGA) and electrochemical measurements. The electrochemical performance
(capacity vs cycle number) of the cathode materials were tested
galvanostatically.
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Novel approaches to the synthesis and treatment of cathode materials for lithium-ion batteriesRodrigues, Isadora R. 07 1900 (has links)
Nous avons mis au point une approche novatrice pour la synthèse d’un
matériau de cathode pour les piles lithium-ion basée sur la décomposition
thermique de l’urée. Les hydroxydes de métal mixte (NixMnxCo(1-2x)(OH)2) ont
été préparés (x = 0.00 à 0.50) et subséquemment utilisés comme précurseurs à la
préparation de l’oxyde de métal mixte (LiNixMnxCo(1-2x)O2). Ces matériaux,
ainsi que le phosphate de fer lithié (LiFePO4), sont pressentis comme matériaux
de cathode commerciaux pour la prochaine génération de piles lithium-ion. Nous
avons également développé un nouveau traitement post-synthèse afin
d’améliorer la morphologie des hydroxydes.
L’originalité de l’approche basée sur la décomposition thermique de
l’urée réside dans l’utilisation inédite des hydroxydes comme précurseurs à la
préparation d’oxydes de lithium mixtes par l’intermédiaire d’une technique de
précipitation uniforme. De plus, nous proposons de nouvelles techniques de
traitement s’adressant aux méthodes de synthèses traditionnelles. Les résultats
obtenus par ces deux méthodes sont résumés dans deux articles soumis à des
revues scientifiques.
Tous les matériaux produits lors de cette recherche ont été analysés par
diffraction des rayons X (DRX), microscope électronique à balayage (MEB),
analyse thermique gravimétrique (ATG) et ont été caractérisés
électrochimiquement. La performance électrochimique (nombre de cycles vs
capacité) des matériaux de cathode a été conduite en mode galvanostatique. / We have developed a novel approach to the synthesis of cathode
materials for lithium-ion batteries, based on the thermal decomposition of urea.
Mixed metal hydroxides (NixMnxCo(1-2x)(OH)2), x = 0.00 to 0.50, were prepared
and subsequently used as precursor for lithiated mixed metal oxide
(LiNixMnxCo(1-2x)O2). These materials along with lithium iron phosphate
(LiFePO4) are being considered as cathode materials for the next generation of
lithium-ion batteries. We have also developed new post-synthetic treatments on
the hydroxides in order to enhance the morphology, which would result in
improved electrode properties.
The novelty of this thesis is that for the first time mixed metal
hydroxides for use as precursors for lithium mixed oxides have been prepared
via a uniform precipitation technique from solution. In addition, we have
proposed new treatments techniques towards the more traditional synthesis
method for mixed metal hydroxides. The results obtained from these two
methods are summarized within two articles that were recently submitted to
peer-reviewed journals.
Within this thesis, all materials were analyzed with X-ray diffraction
(XRD), scanning electron microscopy (SEM), thermal gravimetric analysis
(TGA) and electrochemical measurements. The electrochemical performance
(capacity vs cycle number) of the cathode materials were tested
galvanostatically.
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