EDTA-Complexing Sol-Gel Synthesis of LaFeO3 Nanostructures and Their Gas-Sensing Properties

Perovskite type LaFeO3 have now been successfully synthesized by a sol-gel process based on an ethylene diamine tetraacetic acid (EDTA)-complexing method. The structure and morphology of the products were characterized by x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Based on the experimental results, the average crystallite size of the LaFeO3 nanostructures can be increased from 20.0nm to 34.1nm as the calcination temperature of the precursor increased, ranging from 500 degrees C to 800 degrees C. When the molar ratio of EDTA:total metal ions reaches 1.2:1, the prepared LaFeO3 seems to have a nearly spherical morphology, and the sample has a relatively uniform particle size distribution with an average size of about 40nm. After comprehensive analysis, gas sensor research shows that LaFeO3 nanostructure-based sensors have potential applications in acetone gas monitoring. When exposed to 100ppm acetone, the response of LaFeO3 nanostructures at 250 degrees C was 11.7, the response time was 9s, and the recovery time was 15s. Thus, the facile synthesis route used in this study for synthesizing LaFeO3 nanoparticles could be expected to be extended for the preparation of binary metal oxide gas-sensing materials.