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 20.0 nm to 34.1 nm as the calcination temperature of the precursor increased, ranging from 500°C to 800°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 40 nm. After comprehensive analysis, gas sensor research shows that LaFeO3 nanostructure-based sensors have potential applications in acetone gas monitoring. When exposed to 100 ppm acetone, the response of LaFeO3 nanostructures at 250°C was 11.7, the response time was 9 s, and the recovery time was 15 s. 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.