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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 18, Number 12
BKCSDE 18(12)
December 20, 1997 

Synthesis of La1-xSrxCoO3 (x≤0.2) at Low Temperature from PVA-polymeric Gel Precursors
Ho-Jin Kweon*, Dong Gon Park, Seung-Taik Kuk, Hyu-Bum Park, Keon Kim
Single phase La1-xSrxCoO3 (x≤0.2) was synthesized as a uniform sized 100 nm particulates with relatively high surface area of 20-30 m2/g, at low temperature (≥600 ℃), from a polymeric gel precursors prepared by using poly(vinyl alcohol) as homogenizer. No minor phase developed during the crystallization when polymer/metal mole ratio was higher than 3. As the polymer/metal mole ratio was raised in the gel, the amount of carbonaceous residues in the amorphous solid precursor prepared by heating the gel at 300 ℃ increased. Most of the residues were eliminated by exothermic thermal decomposition around 400 ℃. The amount of residual carbon (less than 1%) left in the crystalline La1-xSrxCoO3 decreased as more polymer was used, eliminating detrimental effect which might be posed by using large amount of organic homogenizer. The crystal structure of La1-xSrxCoO3 synthesized at temperature lower than 800 ℃ was observed to be shifted from rhombohedral to more symmetric cubic. The structure shifted back to rhombohedral as the cubic sample was annealed at 1000 ℃.
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