Enhanced methanol gas-sensing performance of Ce-doped In2O3 porous nanospheres prepared by hydrothermal method

In this work, novel Ce-doped In2O3 porous nanospheres have been prepared by calcining precursors obtained via a facile template-free hydrothermal method. The morphology and structure of the as-prepared samples were characterized by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). FESEM and TEM images showed that as-prepared In2O3 samples were uniform and well-dispersed nanospheres with size of 200–300 nm, which were composed of numerous small nanocrystallites. XRD, ICP, and XPS spectroscopy were used to identify the products structure and the peak shifts in spectroscopies confirmed that the Ce element was doped in cubic In2O3. Compared with pure In2O3 samples, Ce-doped In2O3 porous nanospheres showed excellent sensing performance toward methanol at the operating temperature of 320 °C and had a response of about 35.2–100 ppm methanol, which was much higher than that of the sensor based on pure In2O3 nanospheres. In addition, Ce-doped In2O3 porous nanospheres exhibited good selectivity and long-term stability.