Ultrafast Detection of Low Acetone Concentration Displayed by Au-Loaded LaFeO3 Nanobelts owing to Synergetic Effects of Porous 1D Morphology and Catalytic Activity of Au Nanoparticles

Abstract

Herein, we report on one-dimensional porous Au-modified LaFeO3 nanobelts (NBs) with high surface area, which were synthesized through the electrospinning method. The incorporation and coverage of Au nanoparticles (NPs) on the surface of the LaFeO3 NBs was achieved by adjusting the HAuCl amount in the precursor solution. Successful incorporation of Au NPs was examined by X-ray diffraction, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The gas-sensing performance of both the pure and Au/LaFeO3 NB-based sensors was tested toward 2.5-40 ppm of acetone at working temperatures in the range from room temperature to 180 °C. The gas-sensing findings revealed that Au/LaFeO3 NB-based sensor with the Au concentration of 0.3 wt % displayed improved response of 125-40 ppm of acetone and rapid response and recovery times of 26 and 20 s, respectively, at an optimal working temperature of 100 °C. Furthermore, all sensors demonstrated an excellent response toward acetone and remarkable selectivity against NO2, NH3, CH4, and CO. Hence, the Au/LaFeO3-NB-based sensor is a promising candidate for sensitive, ultrafast, and selective acetone detections at low concentrations. The gas-sensing mechanism of the Au/LaFeO3 sensors is explained in consideration of the catalytic activity of the Au NPs, which served as direct adsorption sites for oxygen and acetone.