Synthesis, characterization and formaldehyde gas sensitivity of La0.7Sr0.3FeO3 nanoparticles assembled nanowires

La0.7Sr0.3FeO3 nanoparticles assembled nanowires were synthesized by a hydrothermal method assisted with cetyltrimethylammonium bromide (CTAB). The hydrothermal temperature was 180 °C and the annealed temperature was 700 °C. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, composition and structural properties of the materials. The results showed that the La0.7Sr0.3FeO3 nanoparticles assembled nanowires had a high aspect ratio (the largest aspect ratio >100); the size of the nanoparticles was about 20 nm and the diameter of the nanowires was about 100–150 nm. The growth mechanism of La0.7Sr0.3FeO3 nanowires was discussed. Gas sensors were fabricated by using La0.7Sr0.3FeO3 nanowires. Formaldehyde gas sensing properties were carried out in the concentration range of 0.1–100 ppm at the optimum operating temperature of 280 °C. The response and recovery times to 20 ppm formaldehyde of the sensor were 110 s and 50 s, respectively. The gas sensing mechanism of La0.7Sr0.3FeO3 nanowires was investigated.

► High aspect ratio La0.7Sr0.3FeO3 nanoparticles assembled nanowires were synthesized by a CTAB assisted hydrothermal method.
► Formaldehyde with low concentration (0.1–100 ppm) was used for gas sensing study.
► The growth mechanism of La0.7Sr0.3FeO3 nanowires was reported.