Selective Detection of NO2 Using Cr-Doped CuO Nanorods

Abstract

CuO nanosheets, Cr-doped CuO nanosheets, and Cr-doped CuO nanorods were prepared by heating a slurry containing Cu-hydroxide/Cr-hydroxide. Their responses to 100 ppm NO2, C2H5OH, NH3, trimethylamine, C3H8, and CO were measured. For 2.2 at% Cr-doped CuO nanorods, the response (R-a/R-g, R-a: resistance in air, R-g: resistance in gas) to 100 ppm NO2 was 134.2 at 250 degrees C, which was significantly higher than that of pure CuO nano-sheets (R-a/R-g = 7.5) and 0.76 at% Cr-doped CuO nanosheets (R-a/R-g = 19.9). In addition, the sensitivity for NO2 was also markedly enhanced by Cr doping. Highly sensitive and selective detection of NO2 in 2.2 at% Cr-doped CuO nanorods is explained in relation to Cr-doping induced changes in donor density, morphology, and catalytic effects.