TY - JOUR
T1 - Effect of carbon shell on stabilization of single-phase lanthanum and praseodymium hexaaluminates prepared by a modified Pechini method
AU - Stoyanovskii, Vladimir O.
AU - Vedyagin, Aleksey A.
AU - Volodin, Alexander M.
AU - Bespalko, Yulia N.
N1 - Funding Information:
This study was funded by the Russian Foundation for Basic Research (grant number 19-03-00660 ).
Funding Information:
The authors are grateful to the Russian Ministry of Science and Higher Education (project AAAA-A17-117041710086-6 ) and the Tomsk Polytechnic University Target Program ‘Science’ (project FSWW-2020-0011 ). Characterization of the samples was performed using the equipment of the Center of Collective Use ‘National Center of Catalysts Research’.
Publisher Copyright:
© 2020 Elsevier Ltd and Techna Group S.r.l.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/12/15
Y1 - 2020/12/15
N2 - A modified Pechini method involving the formation of carbon shell was proposed and used for the synthesis of the unsubstituted lanthanum and praseodymium hexaaluminates with the magnetoplumbite structure. The peculiarities of the LaAlO3 and LaAl11O18 phases' formation were studied in a wide temperature range starting from their appearance at 700 °C and finishing at 1300 °C when the complete phase formation occurs. It was found that the size of the formed hexaaluminate's crystallites is a crucial factor affecting the phase purity of the final product. The critical size of the thermodynamic stability of the LaAlO3 phase is supposed to be 10 nm, which corresponds to the specific surface area of 90 m2/g. The use of a carbon template approach leading to the formation of a core-shell structure during the synthesis procedure allows stabilizing the oxide particles in size and preventing their agglomeration at high temperatures. Depending on the carbon template nature, the carbon content in the samples was found to be 13 wt% (low-carbon-shelled samples) and 40 wt% (high-carbon-shelled samples). In the case of high carbon content, the resulting LaAl11O18 and PrAl11O18 hexaaluminates possess the surface areas as high as 160 m2/g.
AB - A modified Pechini method involving the formation of carbon shell was proposed and used for the synthesis of the unsubstituted lanthanum and praseodymium hexaaluminates with the magnetoplumbite structure. The peculiarities of the LaAlO3 and LaAl11O18 phases' formation were studied in a wide temperature range starting from their appearance at 700 °C and finishing at 1300 °C when the complete phase formation occurs. It was found that the size of the formed hexaaluminate's crystallites is a crucial factor affecting the phase purity of the final product. The critical size of the thermodynamic stability of the LaAlO3 phase is supposed to be 10 nm, which corresponds to the specific surface area of 90 m2/g. The use of a carbon template approach leading to the formation of a core-shell structure during the synthesis procedure allows stabilizing the oxide particles in size and preventing their agglomeration at high temperatures. Depending on the carbon template nature, the carbon content in the samples was found to be 13 wt% (low-carbon-shelled samples) and 40 wt% (high-carbon-shelled samples). In the case of high carbon content, the resulting LaAl11O18 and PrAl11O18 hexaaluminates possess the surface areas as high as 160 m2/g.
KW - Carbon shell
KW - Hexaaluminates
KW - Lanthanum
KW - Phase transformations
KW - Praseodymium
KW - Thermodynamic phase stability
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U2 - 10.1016/j.ceramint.2020.08.088
DO - 10.1016/j.ceramint.2020.08.088
M3 - Article
AN - SCOPUS:85089529579
VL - 46
SP - 29150
EP - 29159
JO - Ceramics International
JF - Ceramics International
SN - 0272-8842
IS - 18
ER -