کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1626042 | 1516443 | 2007 | 10 صفحه PDF | دانلود رایگان |
This paper reports results of studies on the interaction of praseodymium oxide nanocrystals with an amorphous silica. Nano-sized (3–4 nm) amorphous precursor of praseodymium oxide synthesized using a microemulsion technique were supported onto a high surface SiO2 or occluded into SiO2 matrix. Solid state reactions occurring in these binary systems upon heat treatment in air, argon or hydrogen at 800–1100 °C were studied by TEM, XRD, FT-IR and UV–vis spectroscopy. It has been found that morphology of the sample as well as annealing atmosphere influence greatly the phase evolution. At temperatures above 900 °C, nanocrystalline praseodymium silicates of various morphology and crystal structure were obtained. In particular, a new polymorph of Pr2Si2O7, isostructural with I-type Ln2Si2O7 (Ln6[Si4O13][SiO4]2) Ln = Ce, La, has been identified.
Journal: Journal of Alloys and Compounds - Volume 430, Issues 1–2, 14 March 2007, Pages 282–291