fulltext.study @t Gmail

Solid state reactions in highly dispersed single and mixed lanthanide oxide–SiO2 systems

Paper ID Volume ID Publish Year Pages File Format Full-Text
55596 47058 2012 7 PDF Available
Title
Solid state reactions in highly dispersed single and mixed lanthanide oxide–SiO2 systems
Abstract

This paper summarizes our previous studies on the interaction of highly dispersed lanthanide oxides (La, Ce, Pr, Nd and Lu) with amorphous silica and presents new data on the Ce0.5Yb0.5O1.75–SiO2 system. It is shown that at temperatures above 800 °C, chemical reaction between lanthanide oxide and silica may occur leading to formation of silicate phases with unusual structure not observed for bulk like oxide–SiO2 systems. For nano Ce0.5Yb0.5O1.75–SiO2 system results of TEM, SEM and XRD studies revealed that at or above 1000 °C, ytterbium is withdrawn from the mixed oxide and B-type polymorph of Yb2Si2O7 (Yb4[Si3O10][SiO4]) is formed. This polymorph, till now known as high pressure form, is unstable at 1100 °C and transforms into ordinary C-type Yb2Si2O7. Mechanism of silicate formation and its possible role in deactivation of supported catalysts containing lanthanide oxides as active phase or as promoters is discussed.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (200 K)Download as PowerPoint slideHighlights► Ce0.5Yb0.5O1.75 nanoparticles on silica exhibit good structural stability in air to 900 °C. ► Depletion of the oxide in Yb occurs at high temperature due to formation of Yb silicate. ► Yb silicate has Yb4[Si3O10][SiO4] structure, till now observed only at high pressure.

Keywords
Ceria based oxide; Ce–Yb–O; Nanostructured materials; Solid state reactions; Microstructure; Transmission electron microscopy (TEM); Mixed oxide; Ytterbium silicate; Yb4[Si3O10][SiO4]
First Page Preview
Solid state reactions in highly dispersed single and mixed lanthanide oxide–SiO2 systems
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 180, Issue 1, 17 January 2012, Pages 117–123
Authors
, ,
Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us