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Generalized Nonaqueous Sol–Gel Synthesis of Different Transition‐Metal Niobate Nanocrystals and Analysis of the Growth Mechanism
Author(s) -
Zhang Lizhi,
Garnweitner Georg,
Djerdj Igor,
Antonietti Markus,
Niederberger Markus
Publication year - 2008
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200700318
Subject(s) - niobium , nanocrystal , oxide , hydroxide , materials science , crystallization , transition metal , recrystallization (geology) , inorganic chemistry , solvolysis , niobium oxide , dissolution , chemical engineering , chemistry , catalysis , nanotechnology , organic chemistry , metallurgy , paleontology , engineering , hydrolysis , biology
Abstract A general nonaqueous route for the synthesis of phase‐pure transition‐metal niobate (InNbO 4 , MnNb 2 O 6 , and YNbO 4 ) nanocrystals was developed based on the one‐pot solvothermal reaction of niobium chloride and the corresponding transition‐metal acetylacetonates in benzyl alcohol at 200 °C. All samples were carefully characterized by XRD, TEM, HRTEM, and energy‐dispersive X‐ray (EDX) analysis. The crystallization mechanism of these niobate nanocrystals points to a two‐step pathway. First, metal hydroxide crystals and amorphous niobium oxide are formed. Second, metal niobate nanocrystals are generated from the intermediates by a dissolution–recrystallization mechanism. The reaction mechanisms, that is, the processes responsible for the oxygen supply for oxide formation, were found to be rather complex and involve niobium‐mediated ether elimination as the main pathway, accompanied by solvolysis of the acetylacetonate ligands and benzylation reactions.