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Support-shape dependent catalytic activity in Pt/alumina systems using ultra-small (USANS) and small angle neutron scattering (SANS)

Paper ID Volume ID Publish Year Pages File Format Full-Text
53358 46964 2016 9 PDF Available
Title
Support-shape dependent catalytic activity in Pt/alumina systems using ultra-small (USANS) and small angle neutron scattering (SANS)
Abstract

•The effect of catalyst support morphology on catalytic activity was investigated.•Structure of the support materials was characterized by neutron scattering techniques.•Dispersion of Pt on gamma alumina was dependent on the shape of the support.•The different dispersion of Pt led to different catalytic activities.

The correlation between the morphology of catalyst supports and their effect on catalyst dispersion was investigated. The structure of two types of γ-alumina (γ-Al2O3) crystallite particles, rod-like and platelet-like alumina, were measured in 4 orders of length scales, from nanometer to micrometer, using ultra small angle neutron scattering (USANS) and SANS and quantitatively characterized with Hammouda's Generalized Guinier–Porod model. Pt nanoparticles tended to deposit in finer particles and had narrower particle size distribution on the rod-like alumina supports compared to the plate-like alumina supports due to geometrically restricted deposition areas and higher surface curvatures of the rod-like supports. The high diffusion barrier for Pt particles on the highly curved surfaces of the rod-like supports was attributed to be the reason why Pt particles were prevented from diffusing and clustering. While aggregates of the rod-like alumina supports were randomly dispersed without any specific orientation, resulting in high surface area, aggregates of the plate-like alumina supports consisted of a stack of 2–3 layers due to the high van der Waals forces between planar layers, resulting in low surface area. Pt/rod-like alumina supports showed more than 100% higher catalytic activities than Pt/platelet-like alumina supports in model three-way-catalyst (TWC) reactions of CO, NO, and C3H6 conversions at 200–250 °C. Control of shape and aggregation of catalytic support materials in nano–micrometer scale can be an important parameter to improve catalytic performance.

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Keywords
Shape; Catalytic activity; Support materials; Ultra small angle neutron scattering; Small angle neutron scattering
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Support-shape dependent catalytic activity in Pt/alumina systems using ultra-small (USANS) and small angle neutron scattering (SANS)
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 260, 1 February 2016, Pages 46–54
Authors
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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