3D α-Fe2O3 nanorods arrays@graphene oxide nanosheets as sensing materials for improved gas sensitivity

Hybridizing nanostructured metal oxides with grapheme oxide (GO) is highly desirable for the improvement of gas sensing performance of gas sensors. Herein, we develop an in situ fluorine directed solution process combined with heat treatment to grow highly ordered, porous alpha-Fe2O3 nanorods arrays (NRAs) onto graphene oxide (GO) sheets, resulting in flexible three-dimensional nanostructures. The alpha-Fe2O3 NRAs have heights of similar to 50 nm and widths of 10-20 nm, which are densely and vertically attached to both sides of GO sheets, thereby generating an interesting blanket-like geometry. When tested as sensing materials for gas sensors, the nanocomposite displays a high sensitivity of 19.14 toward 50 ppm acetone at a work temperature of 220 degrees C, which was 5.4 times of that of alpha-Fe2O3. Even after 50 days, a stable sensitivity as high as 18.9 toward 50 ppm acetone could be maintained. The improved high sensitivity, fast response and recovery, and extraordinary stability of GO/alpha-Fe2O3 can be attributed to the highly ordered, porous structure and the synergistic effect between alpha-Fe2O3 and GO.