One-step synthesis of polypyrrole/Fe2O3 nanocomposite and the enhanced response of NO2 at low temperature

In order to enhance the gas response of polypyrrole to NO 2 , the polypyrrole/Fe 2 O 3 nanocomposites are synthesized by one-step hydrothermal route. The presence of ferric oxide in composites is demonstrated by XPS, HRTEM and TG analyses. The polypyrrole/Fe 2 O 3 sensor exhibits high selectivity and response to NO 2 at 50 °C. Compared with other polypyrrole/metal oxide materials, the polypyrrole/Fe 2 O 3 materials are easy to be synthesized, and the gas sensor has a higher response of 220.7%, lower detection limit of 0.1 ppm and good linear relationship when the NO 2 concentrations range from 0.1 ppm to 10 ppm. The gas response is greatly improved in comparison with the pure polypyrrole and Fe 2 O 3 . The reason for the improved response is also discussed.