Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报(英文版)

Transactions of Nonferrous Metals Society of China

Vol. 26    No. 3    March 2016

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Effect of catalytic activities of mixed nano ferrites of zinc and copper ondecomposition kinetics of lanthanum oxalate hydrate
H. NAYAK

Department of Chemistry, Orissa University of Agriculture and Technology, Bhubaneswar 751003(Orissa), India

Abstract:Nanostructured zinc-copper mixed ferrite was synthesized using sol-gel method. Different compositions of ferrite, Zn(1-x)CuxFe2O4 (x=0.0, 0.25, 0.50, 0.75), characterized by XRD, reveal single phase inverse spinel in all the samples. With increasing copper content, the crystallite size increases. The surface morphology of all the samples, studied by SEM, shows porous structure of particles. The prepared samples were also analyzed by FT-IR and TEM. Catalytic activity of the samples was studied on lanthanum oxalate decomposition by thermogravimety .The rate constant k has the highest value with x=0.75 and 5% (mole fraction) of the catalyst and is attributed to high copper content, the mixed sites Cu2+-Fe + and/or Cu+-Fe2+ ion pairs besides the one component sites Cu2+-Cu+, Fe3+-Fe2+, as a result of mutual charge interaction. In other words, the increasing activity of mixed oxides is attributed to increase in the content of active sites via creation of new ion pairs. With increasing Zn content, particle size increases. Variation of catalytic activity of ferrite powders is due to the changes of the valence state of catalytically active components of the ferrites, which oxidizes the carbon monoxide released from lanthanum oxalate.

 

Key words: mixed ferrite; spinel; valence induction; catalyst activity; rate constant; lanthanum oxalate

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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