INVESTIGATION OF CATALYTIC ACTIVITIES BY DIFFERENTIAL THERMAL-ANALYSIS

A calorimetric method is proposed to evaluate the catalytic activity o f a solid catalyst with respect to the exothermic oxidation of Volatil e Organic Compounds (VOC). This method employs a differential thermal analyzer in which an inert reference and a catalytically active sample are both fluxed at a constant rate with a reactive gaseous mixture co mposed of an inert gas (N-2 90% vol.), oxygen and VOC, the last typica lly 900 to 5000 ppm. While the temperature is varied according to a pr edefined cycle, the output signal due to the exothermic reaction on th e catalyst is continuously recorded. The design of the test chamber, t he amount of catalyst, the shape of the holders and finally the now ra te and composition of the gaseous mixture should be carefully selected in order to achieve reproducible results.