THERMAL DECOMPOSITION OF LAYERED DOUBLE HYDROXIDES Mg–Al, Ni–Al, Mg–Ga: STRUCTURAL FEATURES OF HYDROXIDE, DEHYDRATED, AND OXIDE PHASES
a:2:{s:4:"TEXT";s:87:"N. N. Leont’eva1, S. V. Cherepanova2,3, V. A. Drozdov1";s:4:"TYPE";s:4:"html";}
1Institute of Hydrocarbons Processing, Siberian Branch, Russian Academy of Sciences, Omsk, Russia
2Boreskov Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
3Novosibirsk State University, Novosibirsk, Russia
Keywords: X-ray diffraction, hydrotalcite, mixed oxide, disordered structure, stacking faults
Abstract
The analysis of the literature data reveals that, as a rule, layered double hydroxides prepared by co-precipitation have an imperfect structure; however, there are different viewpoints on the type of the defects. Thermal decomposition of Mg–Al, Mg–Ga, and Ni–Al hydroxides occurs through dehydration, dehydroxylation, and decarbonization. The first stage affords a layered dehydrated phase with a strongly disordered structure, which is a subject of controversy. Also, the question on the diffusion of cations during thermolysis is still open, i.e., whether the Mg–Al, Mg–Ga and Ni–Al systems degrade with the development of a nanoheterogenous oxide systems or a single-phase mixed oxide, but with very defective structure, is formed.
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