Novel oligovanadate-pillared hydrotalcites
Oligovanadate-pillared hydrotalcite-type layered materials are expected to be shape-selective oxidation catalysts with tunable acid-base character. The preparation and characterization of four oligovanadate-pillared clays are reported here. These are Mg 5Al 2(OH) 14(V 20 7) 0.5·5H 2O, Mg 4Al 2(OH) 1...
Saved in:
Published in | Applied clay science Vol. 10; no. 1; pp. 57 - 67 |
---|---|
Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
01.08.1995
|
Online Access | Get full text |
Cover
Loading…
Summary: | Oligovanadate-pillared hydrotalcite-type layered materials are expected to be shape-selective oxidation catalysts with tunable acid-base character. The preparation and characterization of four oligovanadate-pillared clays are reported here. These are Mg
5Al
2(OH)
14(V
20
7)
0.5·5H
2O, Mg
4Al
2(OH)
12(HV
2O
7)
0.67·
xH
2O, Mg
5.3Al
2(OH)
14.6(V
4O
12)
0.5·2H
2O, and Mg
2Zn
2Al
2(OH)
12 (V
40
12)
0.5·2H
2O.
The novel, one-step synthetic strategy used here was based on the fact that several oligovanadate anions are formed successively in aqueous solutions as a function of pH. For this particular study we focused our attention to the three anions, V
4O
4
−12, HV
20
7
3− and V
2O
7
4−. The pH ranges where these anions exist in highest concentrations are: 6.5 to 8.5 for V
4O
12
4− 8.5 to 10 for HV
2O
7
3−, and 10 to 13 for V
2O
7
4−. These di- and tetravanadate-pillared clays are prepared in one step by carrying out the synthesis at a pH where the desired anion exists in highest concentration. The isolated clays were characterized by elemental analysis, X-ray diffraction, thermal analyses (TGA, DTA), and surface studies. |
---|---|
ISSN: | 0169-1317 1872-9053 |
DOI: | 10.1016/0169-1317(95)00016-W |