Physico-chemical characteristics of cobalt oxides and their catalytic activities

Abstract

Cobalt chalcogenides (oxides and sulphides) have been prepared by a number of methods. Whereas cobalt oxides are p-type semiconductors, most of the cobalt sulphides show a predominantly metallic conductivity. All the samples except cobalt oxide prepared from cobalt carbonate, have low surface areas (2–10 m 2/gm). Both oxides and sulphides show first order kinetics for the decomposition of H 2O 2 (0.5%). The rate constants can be related to the concentration of C 0 3+ ions on the surface. Rate constants for the decomposition of H 20 2 bear a linear relationship with the energy gap for the oxide samples. No definite correlation between the magnetic susceptibility values and catalytic activity could be established. Both oxides and sulphides show the compensation effect, i.e., a linear relationship between the frequency factor and the energy of activation. The work on Tellurides and Selenides is in progress.