Porous α-Fe2O3 nanorods@graphite nanocomposites with improved high temperature gas sensitive properties

Abstract

In order to improve the high temperature sensitivity of α-Fe2O3 based gas sensor, the porous α-Fe2O3 nanorods@graphite nanocomposites were synthesized using a simple low temperature hydrolysis method. A series of analyses were performed to characterize the morphology, structure and composition. As a result, uniform porous α-Fe2O3 nanorods with a length of about 200–300 nm directly grown on the surface of graphite nanoplatelets. When tested as sensing materials for gas sensors, the nanocomposites display a high sensitivity of 16.9 toward 50 ppm acetone at a work temperature of 260 °C, which was 2.2 times of that of pure α-Fe2O3. Even at a work temperature of 320 °C, a stable sensitivity as high as 10.4 toward 50 ppm acetone could be maintained. The improved high temperature sensitivity of porous α-Fe2O3 nanorods@graphite nanocomposites can be attributed to p-n heterojunction, the porous structure of α-Fe2O3 nanorods, the high temperature stability of graphite and large specific surface areas.