Sergei A. Zubkov, Elena D. Finashina, Valery N. Zakharov, Leonid Kustov
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引用次数: 0
Abstract
Chromium-substituted aluminophosphate (CrAPO-5) with the AFI crystal structure was prepared for the first time by using microwave conditions at the stage of gel formation and crystallization. This approach allowed the reduction of the time required for the synthesis of CrAPO-5 from 60–70 h to 6 h. CrAPO-5 metal aluminophosphate prepared by microwave-assisted synthesis is studied by UV-visible and IR spectroscopy and X-ray photoelectron spectroscopy. The material is characterized by the presence of Cr3+ and Cr2+ ions in the framework with predominating Cr3+ ions introduced via isomorphous substitution, as well as some minor amounts of extra-framework Cr3+ species, which are present presumably in the state of α-Cr2O3. The latter species can be partially reduced to Cr2+ species in the presence of CO or H2. XPS study of CrAPO-5 revealed the presence of Cr3+ ions in the framework. A TPR experiment showed that the reduction of chromium starts at about 450–500 °C.
期刊介绍:
Crystals (ISSN 2073-4352) is an open access journal that covers all aspects of crystalline material research. Crystals can act as a reference, and as a publication resource, to the community. It publishes reviews, regular research articles, and short communications. Our aim is to encourage scientists to publish their experimental and theoretical results in as much detail as possible. Therefore, there is no restriction on article length. Full experimental details must be provided to enable the results to be reproduced. Crystals provides a forum for the advancement of our understanding of the nucleation, growth, processing, and characterization of crystalline materials. Their mechanical, chemical, electronic, magnetic, and optical properties, and their diverse applications, are all considered to be of importance.