Hierarchical α-Fe2O3/NiO Composites with a Hollow Structure for a Gas Sensor

Hierarchical alpha-Fe2O3/NiO composites with a hollow nanostructure were synthesized by a facile hydrothermal method. The structures and morphologies of the composites were investigated by different kinds of techniques, including X-ray diffraction, field-emission electron scanning microscopy, transmission electron microscopy, and energy dispersive spectroscopy. Hierarchical alpha-Fe2O3/NiO composites were fabricated by growing the alpha-Fe2O3 nanorods on the surfaces of porous NiO nanosheets with a thickness of similar to 12 nm. The gas sensing properties of hierarchical alpha-Fe2O3/NiO composites toward toluene were investigated using a static system. The response of alpha-Fe2O3/NiO composites to 100 ppm toluene was similar to 18.68, which was 13.18 times higher than that of pure NiO at 300 C. The enhanced response can be attributed to heterojunction. Meanwhile, the rapid response and recovery characteristics were observed because of the porous hollow structural characteristics and catalytic actions of alpha-Fe2O3 and NiO.