Synthesis, Structure and Properties of the System B2O3/Al2O3
T. R. KARPOVA, E. A. BULUCHEVSKIY, A. V. LAVRENOV, N. N. LEONTYEVA, M. V. TRENIKHIN, T. I. GULYAEVA and V. P. TALZI
Institute of Hydrocarbons Processing, Siberian Branch of the Russian Academy of Sciences, Ul. Neftezаvodskаya 54, Omsk 644040 (Russia)
E-mail: ktr@ihcp.oscsbras.ru
Keywords: borate-containing aluminium oxide, phase composition, texture, coordination state of aluminium
Pages: 53–60
Abstract
The effect of chemical composition on the formation of the crystal structure and texture characteristics of the oxide system B2O3–Al2O3 obtained through impregnation of pseudoboehmite with the solutions of ortho-boric acid was studied. It was shown that the modification with boron oxide slows down the crystallization of aluminium oxide. According to the high-resolution TEM data, borate-containing aluminium oxides are composed of amorphous and crystalline primary particles. It was established by means of 27Al MAS NMR and 11В MAS NMR that aluminium atoms in the samples occur in octahedral, tetrahedral and penta-coordination, while boron atoms occur in trigonal and tetrahedral coordinations; their relative content depends on chemical composition. The dependence of the specific surface of B2O3–Al2O3 system on its composition has an extremal character; the maximum is achieved with B2O3 content 5 mass %.
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