The preparation and gas sensitivity study of polypyrrole/zinc oxide

Polypyrrole (PPy) was prepared by chemical oxidation polymerization, analyzed by FT-IR, elemental analysis and HRTEM, and studied for gas sensitivity. It suggested that PPy had sensitivity to NH3, H2S and NOx, and showed irreversibility to NO, gas. The organic-inorganic hybrid materials PPy/ZnO with different PPy weight percents were prepared by mechanical mixing, and the sensitivity study of the materials to toxic gases NH3, H2S, NOx was carried out at different operating temperatures 30, 60, and 90 degrees C. It was found that PPy/ZnO materials (PPy(1%)/ZnO, PPy(3%)/ZnO, PPy(5%)/ZnO, PPy(10%)/ZnO, PPy(20%)/ZnO) had better selectivity and reversibility to NO, than pure PPy, and much lower working temperature than the reported working temperature of ZnO (about 350-450 degrees C). Their sensitivity increased with the increasing concentration of NOx at particular working temperature, and among them PPy(10%)/ZnO had the maximum sensitivity to NO, in the same condition. They showed no response to 1000, 1500, 2000 ppm NH3 or H2S. The response mechanism of PPy/ZnO materials to NO, was discussed. (c) 2006 Elsevier B.V. All rights reserved.