fulltext.study @t Gmail

Anomalous diffusion during isopropanol decomposition on (ZrO2)1−x (CeO2)x catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
42881 45944 2009 12 PDF Available
Title
Anomalous diffusion during isopropanol decomposition on (ZrO2)1−x (CeO2)x catalysts
Abstract

In this work the effect of composition of (ZrO2)1−x (CeO2)x catalysts on the ratio γ = Ec/Ed between the activation energies for the isopropanol decomposition, estimated in the chemical reaction (Ec) and the diffusion (Ed) controlled regimes, was studied. The solid catalysts with x = 0.0; 0.2; 0.5; 0.8 and 1.0 were prepared by heating the precursors at 400, 600 and 800 °C and characterized by N2 porosimetry, X-ray diffraction, SEM/EDS analysis and NH3/TPD. Their catalytic activity for the decomposition of isopropanol in the temperature range 200–400 °C was probed in a tubular flow reactor. The estimated Arrhenius plots showed a distinct and well-defined change of slopes corresponding to alternation from the chemical to the internal diffusion-controlled regime of the process. The ratio γ = Ec/Ed of the corresponding activation energies was found equal to γ ≈ 1 for x = 0.0, meaning total lack of diffusion limitations, and converges to γ ≈ 2 for x = 1.0, corresponding to classical internal diffusion control. For 0 < x < 1 the values of 1 < γ < 2 signify anomalous diffusion related linearly to some compositional property of the (ZrO2)1−x (CeO2)x catalysts. The origin of this phenomenon is discussed in relation to the variable binding strength and friction of movement of the isopropanol species on the more active ZrO2 and the less active CeO2 nanoparticles of the solid catalysts.

Graphical abstractThe decomposition of isopropanol on (ZrO2)1−x (CeO2)x catalysts shows anomalous diffusion effects related linearly to their composition x. The origin of this phenomenon is related to the variable friction of the reacting species along their path from the inactive CeO2 particles (dark) to the active ZrO2 particles (white).Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Anomalous diffusion; (ZrO2)1−x (CeO2)x catalysts; Isopropanol decomposition; Activation energy
First Page Preview
Anomalous diffusion during isopropanol decomposition on (ZrO2)1−x (CeO2)x catalysts
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: Applied Catalysis A: General - Volume 364, Issues 1–2, 31 July 2009, Pages 199–210
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