纳米晶LaCo_xFe_(1-x)O_3的合成、表征及湿敏特性(英文)

Synthesis, Characterization and Humidity Sensitive Properties of Nanocrystalline LaCo_xFe_(1-x)O_3

采用PEG溶胶-凝胶法合成了纳米晶LaCoxFe1-xO3,并用DTA-TGA、XRD以及SEM对样品进行表征.结果表明,所有样品的原粉在600℃焙烧下都形成了稳定的钙钛矿纳米晶,Co含量对形成纳米晶的固相反应和纳米晶的平均粒子尺寸都有明显的影响.此外,还研究了纳米晶LaCoxFe1-xO3的湿敏特性,发现在所有的样品中,LaCo0.3Fe0.7O3表现出比其它样品好的湿敏特性,但是此材料只在相对湿度(RH)大于54%时对湿度的变化有较高的灵敏度,掺杂适量的Na2CO3可以改善此材料的湿敏特性,使它在全程湿度范围(RH11%-95%)内对湿度变化都有很好的响应.

The nanocrystalline LaCoxFe1-xO3 with different concentrations of Co was prepared by polyethylene glycol （PEG） sol-gel method and characterized by differential thermal analysis and thermal gravimetric analysis （DTATGA）, X-ray diffraction （XRD）, and scanning electron microscope （SEM）. It was found that the crystal structure of perovskite-type could be obtained at 600 ℃, and the concentration of Co had significant effects on the solid-state reaction and the average particle size of the obtained nanocrystals. Furthermore, the humidity-sensiitive properties of nanocrystalline LaCoxFe1-xO3 were investigated, and it was found that LaCo0.3Fe0.7O3 exhibited higher sensitivity to humidity compared with other samples. The addition of Na2CO3 improved the humidity-sensitive properties of this sample, and made its response to humidity good in the whole humidity range of 11%-95% relative humidity （RH）.