Determination of chlorine in air using ZnO modified with gallium and indium oxides

Abstract

We examine the possibility of detecting Cl2 in flowing air at temperatures from 150 to 350°C using polycrystalline ZnO containing additions of gallium and indium oxides. ZnO modified with gallium via impregnation has a fast, stable, well-reproducible response and a short relaxation time. Its response passes through a maximum at 250°C. The interaction is not complicated by formation of chlorination products. In the range 5−500 ppm, its resistance is a linear function of the square root of Cl2 concentration.