Cu-doped α-Fe2O3 hierarchical microcubes: Synthesis and gas sensing properties

Monodisperse and uniform pure and Cu-doped α-Fe2O3 cubes with a hierarchical architecture piled up nanoparticles as secondary units were obtained via a low-cost and environmentally friendly hydrothermal route. The structure and morphology of the as-synthesized products were characterized by X-ray diffraction (XRD), field-emission electron microscopy (FESEM), and transmission electron microscopy (TEM). The XRD results indicated that the lattice constants of doped samples were slightly smaller than that of the pure sample due to Cu incorporation. A comparative gas sensing study between the Cu-doped α-Fe2O3 and pure α-Fe2O3 cubes was performed to demonstrate the superior gas sensing properties of the doped samples. It was found that the sensor based on Cu-doped α-Fe2O3 (3.0 wt%) had a response of 19–100 ppm C2H5OH, which was about three times higher than that of the pure α-Fe2O3 nanostructures at the same operating temperature (225 °C).