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

作者：Azad Abdul Majeed^*; Duran Martin J

来源：Applied Catalysis A: General , 2007, 330: 77-88.

DOI：10.1016/j.apcata.2007.06.036

• nanoscale doped-ceria supports
• noble metals
• metal oxides
• logistic fuels
• steam reforming
• electron microscopy
• sulfur tolerance
• coking phenomenon

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 degrees 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 H-2 yield. It was found that the addition of metal oxide additives yielded more stable and sulfur-tolerant formulation. Rhodium-alone and the rhodiurn + metal-oxide formulations outperformed their palladium-bearing analogs.

• 出版日期2007-10-10