Structural and Surface Acid/Base Properties of Hydrotalcite-Derived MgAlO Oxides Calcined at Varying Temperatures
✍ Scribed by Jianyi Shen; Mai Tu; Chen Hu
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 298 KB
- Volume
- 137
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
This paper describes the influence of calcination temperature on bulk and surface properties of MgAlO binary oxide derived from the hydrotalcite precursor. MAS 27 Al NMR revealed that significant phase transitions occurred in the samples calcined at 673, 873, and 1073 K. These transitions seem to be important in determining the surface acid/base properties of the samples. Microcalorimetric adsorptions of NH 3 and CO 2 showed that the acidity of these samples decreases in the order: -Al 2 O 3 > 673 K > 873 K+1073 K, while the basicity follows the order: MgO > 873 K > 1073 K > 673 K. IR spectroscopy revealed that the surface acid/base sites of the calcined hydrotalcite samples are mainly Lewis type.