Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/91830
Title: Thermal evolution of cobalt hydroxides: A comparative study of their various structural phases
Authors: Xu, Z.P. 
Zeng, H.C. 
Issue Date: Nov-1998
Source: Xu, Z.P.,Zeng, H.C. (1998-11). Thermal evolution of cobalt hydroxides: A comparative study of their various structural phases. Journal of Materials Chemistry 8 (11) : 2499-2506. ScholarBank@NUS Repository.
Abstract: Through an atmosphere-controlled method, a new phase of hydrotalcite-like Co hydroxide with mixed valent states has been synthesised, along with preparations of known α and β phases. Structural and thermal behaviours of all the Co hydroxides have been compared. Three major stages of decomposition are found: (i) 149-164°C for dehydration of interlayer water, (ii) 185-197°C and (iii) 219-222°C for dehydroxylation of hydrotalcite- and brucite-like phases, respectively. Intercalated nitrate anions in hydrotalcite-like phases decompose largely during stage (ii). The oxide Co3O4 starts to form at temperatures as low as 165°C especially for hydrotalcite-like phases. An intermediate compound, HCoO2, which is formed thermally, decomposes at 258-270°C. The Co3O4 oxide converts into CoO at 842-858 and 935-948°C respectively in nitrogen and air, which is much lower than the previously reported range of 1000-1200°C. Surface areas of calcined samples are found to be proportional to the intercalated anion content. The catalytic activity of the resultant Co3O4 oxides with nitrous oxide is 7.2-8.2 mmol N2O g-1 h-1 at 375°C, which is comparable to some reported active catalyst systems.
Source Title: Journal of Materials Chemistry
URI: http://scholarbank.nus.edu.sg/handle/10635/91830
ISSN: 09599428
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

Page view(s)

58
checked on Apr 20, 2018

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.