Studies on the Structure of Mg–Al and Ni–Al Oxide Carriers Obtained from Layered Double Hydroxides for Hydrocarbon–Processing Catalysts
N. N. LEONTYEVA1, S. V. CHEREPANOVA2, O. B. BELSKAYA1, V. A. DROZDOV1 and V. P. TALZI1
1Institute of Hydrocarbons Processing, Siberian Branch of the Russian Academy of Sciences, Ul. Neftezàvodskàya 54, Omsk 644040 (Russia)
E-mail: n_n_leonteva@list.ru
2Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Pr. Akademika Lavrentyeva 5, Novosibirsk 630090 (Russia)
Keywords: borate–containing aluminium oxide, phase composition, texture, coordination state of aluminium
Pages: 61–69
Abstract
TThe structure of oxides obtained by the calcination of layered Mg–Al and Ni–Al (Mg/Al = Ni/Al = 2 : 1) double hydroxides with the structure of hydrotalcite. It is demonstrated that the formation mechanisms for the oxides are different: the Mg–Al oxide retains the original cation ratio, whereas the structure of the oxide formed represents a kind of layered defective spinel. Calcining the Ni–Al hydroxide results in the fact that the majority of Al3+ ions reaches the surface of the oxide particles, thereby forming aluminum hydroxide with retaining the nickel oxide phase in the course of hydration. It is established that, depending on the number of aluminum atoms in the bulk of the particles there are different structures of oxides formed, those determine the oxide ability either of restoring the layered oxide structure in the case of Mg–Al hydrotalcite, or saving the structure Ni–Al oxide in the course of hydration.
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