High-sensitivity and high-selectivity detection of methanol based on La-doped SnO 2 sensor

Pure SnO 2 and La-doped SnO 2 nanocomposite were prepared through hydrothermal method, and their gas sensing performances were studied. Results indicate that the sensing response of the 5 wt% La-doped SnO 2 nanocomposite reached 29.5 when exposed to 75 ppm methanol at the optimal operating temperature of 220 °C, which was over seven times larger than that of pure SnO 2 nanoparticles. In addition, the response and recovery time were shortened to 12 s and 7 s, respectively. Moreover, the 5 wt% La-doped SnO 2 nanocomposite presents a good selectivity toward methanol among methanal, methanol, ammonia, acetone and benzene gases. The improvement in the gas sensing properties of the 5 wt% La-doped SnO 2 nanocomposite toward methanol can be attributed to the smaller crystallite size, larger surface area and the modified chemical nature of nanocomposite surface.