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

Abstract

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.