Porosity of carbon films applied to chemical sensor construction

Abstract

Investigations on the basic properties of carbons applicable to the construction of semiconducting gas sensors are presented. Development of pore structure of such carbons is considered as the function of carbonisation temperature and chemical modification of the carbons. The chemical modification consisted in the premixing of furfuryl alcohol with an aqueous solution of sodium acetate. The carbons tested were prepared by simulating the “spry pyrolysis” technique. The Na-modification resulted in an increase of the Wo value (the Dubinin-Radushkevich adsorption model) of the carbon films upon increasing the carbonisation temperature while the average pore diameter L was constant. The pore structure in the case of Na-modified carbons was the result of Na2CO3 microcrystallite formation (from CH3COONa) inside the carbon skeleton and their subsequent reaction with the carbon matrix.