NO2 sensing properties of SmFeO3 porous hollow microspheres

Porous hollow microspheres of SmFeO3 were prepared from a simple process involving a metal organic framework (MOF) compound as the templating precursor. With a diameter of about 2 μm, these hollow-centered microspheres are formed by nanoporous thin walls of SmFeO3. Chemoresistive gas sensors based on these microspheres exhibits excellent sensing performance on NO2 at 200 °C, including high sensitivity (response of 10.2 under 200 ppb) with detection limit as low as 50 ppb, high selectivity, and reasonably short time for response and recovery (369 s/478 s). The superior sensing response over other SmFeO3-based NO2 sensors can be ascribed to the electron-accepting reactions during NO2 adsorption, which is facilitated by the special morphological features of the microsphere.