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Development of ceria-supported sulfur tolerant nanocatalysts: Rh-based formulations

Paper ID Volume ID Publish Year Pages File Format Full-Text
43450 45970 2007 12 PDF Available
Title
Development of ceria-supported sulfur tolerant nanocatalysts: Rh-based formulations
Abstract

The conversion of logistics fuels to hydrogen by steam reforming is attractive but poses great challenge since they contain sulfur up to about 3000 ppm leading to catalyst deactivation due to sulfur poisoning. In this paper, we report the fabrication of nominally doped nanoscale ceria-supported rhodium catalyst matrices for their performance evaluation in sulfur-laden fuel streams. Systematic structural and microstructural characterization of the catalysts was carried out before and after the steam reforming and simulated experiments in sulfur-containing streams (50 ppm < S < 1000 ppm) over a wide range of temperature and duration, to speculate and understand the deactivation mechanism and the sulfur tolerance aspects. Steam reforming of toluene as a model fuel without or with 50 ppm sulfur (as thiophene) was carried out at 825 °C and steam-to-carbon (S/C) ratio of 3. The performance of catalysts with bimetal (Rh + Pd) dispersion in small but equal concentrations was found to be the best both in terms of sulfur tolerance and percent H2 yield. It was found that the addition of metal oxide additives yielded more stable and sulfur-tolerant formulation. Rhodium-alone and the rhodium + metal-oxide formulations outperformed their palladium-bearing analogs.

Graphical abstractPerformance of nominally doped nanoscale ceria-supported rhodium catalyst matrices in sulfur-laden fuel streams was evaluated. Catalysts with bimetal (Rh + Pd) dispersion were found to be very promising in terms of sulfur tolerance and percent H2 yield. Addition of a metal oxide additive provides even higher stability and sulfur tolerance.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Nanoscale doped-ceria supports; Noble metals; Metal oxides; Logistic fuels; Steam reforming; Electron microscopy; Sulfur tolerance; Coking phenomenon
First Page Preview
Development of ceria-supported sulfur tolerant nanocatalysts: Rh-based formulations
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 330, 10 October 2007, Pages 77–88
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis