16065-90-0Relevant articles and documents
Photochemical Electron Transfer from Cerous Ions to the Lowest Excited State of Uranyl Ions in Aqueous Media, Studied by Laser Photolysis
Rosenfeld-Grunwald, T.,Brandels, Marek,Rabani, Joseph
, p. 4745 - 4750 (1982)
A high-intensity beam of a Nd laser at 353.3 nm was used to produce the first excited state of the uranyl ion.Cerous ions, in acidic aqueous solutions,were found to react with it.The products of this reaction are ceric ions and uranium(V) ions.The absorption of the Ce(IV) ions was followed and the yields and decay kinetics of the ions were studied.The quantum yield of Ce(IV) formation is 0.85 +/- 0.15, 1.00 +/- 0.2, and 0.95 +/- 0.25 in 0.1-0.5 M H2SO4, 0.57-2 M HNO3, and 2 M HClO4, respectively.The photochemical electron transfer is followed by a reaction of the products to produce the ground states of the initial reactants by a second-order reaction.The rate constant of this reaction is 5 * 106 M-1 s-1 in 0.1-0.5 M H2SO4, ca. 2 * 107 M-1 s-1 in 2 M HNO3, and ca. 3 * 107 M-1 s-1 in 2 M HClO4.The interpretation of the photochemical results is supported by pulse radiolysis experiments.
Tikhonova, L. P.,Kovalenko, A. S.
, (1983)
Hydrolysis of tetravalent cerium for a simple route to nanocrystalline cerium dioxide: An in situ spectroscopic study of nanocrystal evolution
Ikeda-Ohno, Atsushi,Hennig, Christoph,Weiss, Stephan,Yaita, Tsuyoshi,Bernhard, Gert
, p. 7348 - 7360 (2013)
Despite the rapid developments in recent nanocrystal research and their expanding applications, the evolution mechanism of nanocrystals remains veiled for the most part due to the lack of appropriate analytical techniques. Here we demonstrate one promising multi-spectroscopic approach for the in situ investigation of nanocrystal evolution. That is, the formation of nanocrystalline cerium dioxide (NC-CeO2) has been probed by dynamic light scattering (DLS), X-ray absorption spectroscopy (XAS) and high-energy X-ray scattering (HEXS). The obtained results indicate that the fine colloidal particles of NC-CeO2 are formed in an acidic aqueous solution simply through the hydrolysis of the initial precursor of small oligomer Ce IV species. This information on how NC-CeO2 evolves is fundamental to simplifying and alleviating the synthetic strategy for NC-CeO2 production. Nanocrystal evolution: A multi-spectroscopic approach has revealed that the hydrolysis of tetravalent cerium (Ce IV) produces a colloidal solution of fine cerium dioxide (CeO 2) nanocrystals (see figure). A simple synthetic concept of nanocrystalline metal oxides is proposed based on the obtained results. Copyright
Growth of spherulitic crystal patterns in a Belousov-Zhabotinski type reaction system
Yadav, Narendra,Srivastava
, p. 1080 - 1087 (2011/07/08)
The growth of spherulitic crystal patterns in a Belousov-Zhabotinski (BZ) type reaction system by using acetyl acetone (AA)-succinic acid (SA) as dual organic substrates has been reported. The reaction system in the liquid phase has been found to show concentric ring-like wave patterns. A colloidal phase composed of numerous fine particles has also been observed during reaction. The solid phase nucleation has been found to occur in the colloidal phase, which leads to the formation of some stable nucleus centers. The solid phase nucleus has been found to grow in symmetric crystal patterns, with the progress of reaction, exhibiting spherulitic morphology. The possible growth behavior of spherulites has also been discussed. The spherulitic structure composed of fine crystal fibrils diverging from a common center have been observed by a scanning electron microscopy (SEM) technique. The polymorphic crystalline phase, found in spherulites has been supported by thermal characterization (TGA/DTA) and X-ray diffraction (XRD) patterns of crystal materials. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011.
