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Thermal transformations of Cu–Mg (Zn)–Al(Fe) hydrotalcite-like materials into metal oxide systems and their catalytic activity in selective oxidation of ammonia to dinitrogen
Thermal transformations of Cu–Mg (Zn)–Al(Fe) hydrotalcite-like materials into metal oxide systems and their catalytic activity in selective oxidation of ammonia to dinitrogen
Thermal transformations of Cu–Mg (Zn)–Al(Fe) hydrotalcite-like materials into metal oxide systems and their catalytic activity in selective oxidation of ammonia to dinitrogen
autor:
Jabłońska Magdalena , Chmielarz Lucjan , Węgrzyn Agnieszka , Guzik Katarzyna , Piwowarska Zofia , Witkowski Stefan , Walton Richard I., Dunne Peter W., Kovanda František
Layered double hydroxides (LDHs) containing
$Mg^{2+}$, $Cu^{2+}$ or $Zn^{2+}$ cations in the $Me^{II}$ positions and $Al^{3+}$
and $Fe^{3+}$ in the $Me^{III}$ positions were synthesized by co-
precipitation method. Detailed studies of thermal trans-
formation of obtained LDHs into metal oxide systems were
performed using high temperature X-ray diffraction in
oxidising and reducing atmosphere, thermogravimetry
coupled with mass spectrometry and temperature-pro-
grammed reduction. The LDH samples calcined at 600 and
900 $^{o}\textrm{C}$ were tested in the role of catalysts for selective
oxidation of ammonia into nitrogen and water vapour. It
was shown that all copper congaing samples presented high
catalytic activity and additionally, for the Cu–Mg–Al and
Cu–Mg–Fe hydrotalcite samples calcined at 600 $^{o}\textrm{C}$ rela-
tively high stability and selectivity to dinitrogen was
obtained. An increase in calcination temperature to 900 $^{o}\textrm{C}$
resulted in a decrease of their catalytic activity, possibly
due to formation of well-crystallised metal oxide phase which are less catalytically active in the process of selective oxidation of ammonia.
wydział: instytut / zakład / katedra:
Wydział Chemii : Zakład Chemii Nieorganicznej, Wydział Chemii : Zakład Technologii Chemicznej