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The decomposition course, intermediates and final products of praseodymium acetate monohydrate Pr(CH 3 COO) 3 ·H 2 O in different gas atmospheres (O 2 , N 2 or H 2 ) were characterized using thermal analysis, X-ray diffractometry and infrared spectroscopy. Praseodymium acetate decomposes in five mass loss events leading to the formation of the intermediate products Pr(OH)(CH 3 COO) 2 , PrO(CH 3 COO) and Pr 2 O 2 CO 3 . Results obtained indicate that praseodymium acetate decomposes into a number of intermediate products whose chemical structure is independent on the gas atmosphere applied, but the kinetics of their formation and subsequent decomposition is considerably enhanced in O 2 atmosphere. The final product at 700 °C was found to be praseodymium oxide Pr 6 O 11 in O 2 and N 2 , but mixed with minority Pr 2 O 3 in H 2 atmosphere. Surface texture and 2-propanol decomposition activity of the final products at 700 °C were determined by means of N 2 sorptiometry and in situ IR spectroscopy. The final products in O 2 and N 2 were slightly more active catalysts toward 2-propanol decomposition the latter was of higher selectivity toward the alcohol dehydration, which is suggested to be correlated with the evolution of a narrower mesoporous structure on its surface. |
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