Synthesis of gadolinia-doped ceria gels and powders from acetylacetonate precursors
We report here the synthesis of gadolinia-doped ceria (GDC) gels and powders via the sol–gel method using cerium acetylacetonate and gadolinium acetylacetonate as precursors. The dependence of the morphology and nature of the sol–gel product on synthesis parameters has been investigated in detail. The sol is synthesized and gelled under various conditions to study the effects of (1) the hydrolysis ratio, (2) the reaction temperature, (3) the reaction time, (4) the addition of acetic acid, and (5) the as-synthesized condition versus the condition with subsequent calcination at 600 °C. It is found that all of these parameters exert strong influence on the morphology and nature of the sol–gel product. Crystalline GDC gels are produced when hydrolysis and gelation are carried out at 55–125 °C. Monolithic gels with low porosity and only micro cracks (shorter than 800 μm and less than 7 μm wide) can be formed with the proper drying procedure at ambient pressure. Although thermal exposure to 600 °C leads to grain growth, the size of GDC crystallites is still less than 9 nm after the thermal exposure.
KeywordsCerium acetylacetonate Gadolinium acetylacetonate Gadolinia-doped ceria oxide Sol–gel processing
The first author, Leon Shaw, would like to thank the University of Connecticut for granting a sabbatical leave to conduct research at MIT. The second author, CS, is grateful to the State Scholarship Fund provided by Wuhan University of Technology, China. Ms. Xuefei Wan’s help in measuring the pore size and its distribution of some samples and Mr. Yang Zhong’s assistance in collecting XRD patterns of several samples are greatly appreciated.
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