La/SnO2 nanoparticles: Hydrothermal synthesis, structure, and sensing performance in a high relative humidity environment

Abstract

In this work, a simple one-step hydrothermal synthesis of La doped SnO2 nanocomposites was studied. The structure, morphology, specific surface area, and chemical composition were determined by XRD, SEM, BET, and XPS techniques. The gas sensing performance of SnO2 and La/SnO2 nanocomposites with varied La doping dosages on n-butanol gas was systematically investigated. The results manifested that under the testing environment (50 % relative humidity and 30 °C), La doped SnO2 nanocomposite sensor presented high response (69), excellent selectivity, good repeatability and long-time stability to n-butanol gas at 160 °C. Especially, the 7 mol% La doped SnO2 sensor displayed a 5.9 times higher response to 50 ppm n-butanol than the SnO2 sensor. In comparison with bare SnO2, La doping increased the band gap value of 7 mol% La/SnO2 nanocomposite by 6.23 %, decreased particle size by 11.83 %, and increased the oxygen defect concentration by 6.07 %. Due to the synergistic effect of the above factors, the gas sensing performance of La doped SnO2 nanocomposites towards n-butanol gas was enhanced. Therefore, La doped SnO2 nanocomposites might be a potential gas sensing material for monitoring n-butanol gas at relatively high humidity.