A comparative study of thermal decomposition behaviour of Zn-Cr,Zn-Cr-Al and Zn-Al type layered double hydroxides

Hydrolysis of ZnO in acidic pH provides a facile route for synthesis of layered double hydroxides (LDH) bearing Zn²⁺ with Cr³⁺ and Al³⁺ without having carbonate ion in the inter-layer position. The thermal decomposition of the prepared LDH show that with the increase of Cr³⁺ content in the system there is an increase in the thermal stability of the compounds. In case of Zn-Cr LDH there is a non-mass loss transition around 420°C. Segregation of parent LDH structure to a bivalent oxide and a spinel takes place in both Zn-Cr and Zn-Al LDH only at temperatures above 550°C.Authors are grateful to Director R. R. L. Jorhat for his kind permission to publish the work, as well as acknowledgement is due to Prof. Herbert Poellmann of University of Halle, Germany for some powder XRD runs. Also, acknowledgement is due to Ministry of Environment and Forests, Govt. of India for some financial assistance.