Hydrothermal synthesis of Ce-doped hierarchical flower-like In2O3 microspheres and their excellent gas-sensing properties

Pure and 1-5 mol% Ce-doped hierarchical flower-like In2O3 microspheres with uniform sizes were synthesized via environment friendly one-step hydrothermal method. Their phase structures, morphologies properties and element composition were investigated by different kinds of techniques, including X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectric spectroscopy (XPS). Their gas-sensing properties were tests for several kinds of Volatile Organic Compounds (VOCs). The results indicated that Ce doping could greatly improve sensing performances of In2O3 gas sensors. Among all the samples (0, 1, 3 and 5 mol% Ce-doped In2O3), 3 mol% Ce-doped In2O3 exhibited the highest response toward 200 ppm acetone at 250 °C, having a response of 41.8, which was about 4 times higher than pure In2O3. Furthermore, good repeatability and long term stability were achieved, showing its prospect for excellent acetone gas sensor with high performance.