PdZnAl catalysts for the reactions of water-gas-shift, methanol steam reforming, and reverse-water-gas-shift

PdZn catalysts have been studied for WGS reaction. Although PdZn alloys are active WGS catalysts, WGS is not involved in methanol steam reforming. RWGS reaction could be one of the sources for small amount of CO formation in methanol steam reforming. ▪ Pd/ZnO/Al 2O 3 catalysts were studied for water...

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Published in:Applied catalysis. A, General Vol. 342; no. 1; pp. 63 - 68
Main Authors: Dagle, R.A., Platon, A., Palo, D.R., Datye, A.K., Vohs, J.M., Wang, Y.
Format: Journal Article
Language:English
Published: Amsterdam Elsevier B.V 30-06-2008
Elsevier
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Summary:PdZn catalysts have been studied for WGS reaction. Although PdZn alloys are active WGS catalysts, WGS is not involved in methanol steam reforming. RWGS reaction could be one of the sources for small amount of CO formation in methanol steam reforming. ▪ Pd/ZnO/Al 2O 3 catalysts were studied for water-gas-shift (WGS), methanol steam reforming, and reverse-water-gas-shift (RWGS) reactions. WGS activity was found to be dependent on the Pd:Zn ratio with a maximum activity obtained at approximately 0.50, which was comparable to that of a commercial Pt-based catalyst. The catalyst stability was demonstrated for 100 h time-on-stream at a temperature of 360 °C without evidence of metal sintering. WGS reaction rates were approximately 1st order with respect to CO concentration, and kinetic parameters were determined to be E a = 58.3 kJ mol −1 and k 0 = 6.1 × 10 7 mol −1. During methanol steam reforming, the CO selectivities were observed to be lower than the calculated equilibrium values over a range of temperatures and steam/carbon ratios studied while the reaction rate constants were approximately of the same magnitude for both WGS and methanol steam reforming. These results indicate that although Pd/ZnO/Al 2O 3 are active WGS catalysts, WGS is not involved in methanol steam reforming. RWGS rate constants are on the order of about 20 times lower than that of methanol steam reforming, suggesting that RWGS reaction could be one of the sources for small amount of CO formation in methanol steam reforming.
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USDOE
AC05-76RL01830
PNNL-SA-58369
ISSN:0926-860X
1873-3875
DOI:10.1016/j.apcata.2008.03.005