Nanostructured perovskite oxides – LaMO3 (M=Al, Co, Fe) prepared by co-precipitation method and their ethanol-sensing characteristics

Nanostructured La-based perovskite oxides − LaMO3 (M=Al, Co, Fe) were synthesized by a new co-precipitation procedure using metal nitrate and carbonate salts as starting materials. X-ray diffraction and energy dispersive X-ray spectroscopic results confirmed the formation of single-phase nanocrystalline perovskite oxides with high purity. Characterizations by scanning/transmission electron microscopy and nitrogen adsorption revealed that LaAlO3 was produced in the form of rectangular porous nanorods exhibiting much larger surface area and porosity compared with densely aggregated LaCoO3 particles and loosely clustered LaFeO3 nanoparticles with cracked-egg morphologies. The materials were characterized for gas sensing towards ethanol at 200–350 °C. From gas-sensing results, the LaAlO3 sensor displayed n-type gas-sensing behaviors with considerably higher ethanol response than p-type LaFeO3 and LaCoO3 sensors, respectively. In particular, the LaAlO3 sensor exhibited a high response of 16.45–1000 ppm ethanol and excellent ethanol selectivity against NO2, SO2, CO and H2 at 350 °C. The superior gas-sensing performances could be attributed to the effective receptor function, transducer function and utility factor of LaAlO3 nanorod structures prepared by the co-precipitation method.