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The CO2 reforming of CH4 over Ni/La2O3/α-Al2O3 catalysts: The effect of La2O3 contents on the kinetic performance

Paper ID Volume ID Publish Year Pages File Format Full-Text
43343 45965 2007 10 PDF Available
Title
The CO2 reforming of CH4 over Ni/La2O3/α-Al2O3 catalysts: The effect of La2O3 contents on the kinetic performance
Abstract

The aim of this work is to quantitatively investigate the effect of La2O3 contents on the intrinsic activity of Ni active sites for the CO2 reforming of CH4 on Ni/La2O3 (1, 2, 4, and 6 wt%)/α-Al2O3 catalysts using steady and pulse kinetic methods. The Ni particle sizes were decreased with increasing La2O3 contents. And the 4-La catalyst had the most Ni–H species. The Ni active sites on the 4-La catalyst showed the highest reforming activity and the lowest activation energy. Among CH4, CO2, CO, and H2, only CH4 reaction orders were not zero and they were affected by the La2O3 contents. In 550–600 °C, the CH4 dissociation is a rate-determining step for the reforming reaction on the Ni/La2O3/α-Al2O3 catalysts. The 4-La catalyst gave the highest reforming activity because the CH4 dissociation was a structure sensitive reaction and 4-La catalyst has the most suitable Ni particle size. In 650–750 °C, the CH4 dissociation and the formation of Ni–H reached equilibration and the reaction between CHx species with La2O2CO3 became the rate-determining step. The 4-La catalyst with the most Ni–H could keep the highest x value of CHx intermediates, leading to the highest reforming activity in 650–750 °C. Therefore, the La2O3 contents on the catalysts tuned the Ni particle sizes and Ni–H amounts on the catalysts, which lead to higher reforming activity on the 4-La catalyst.

Graphical abstractThe contents of La2O3 in the Ni/La2O3 (1, 2, 4, and 6 wt%)/α-Al2O3 catalysts influence the Ni particle size and Ni–H amount on the catalysts. The catalyst with 4 wt% La2O3 with the most suitable Ni particle size and the most amount of Ni–H leads to the highest performance for CH4/CO2 reforming per Ni active site.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Kinetics; Reforming; CH4; CO2; Ni/La2O3/α-Al2O3
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The CO2 reforming of CH4 over Ni/La2O3/α-Al2O3 catalysts: The effect of La2O3 contents on the kinetic performance
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 331, 2007, Pages 60–69
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