CO preferential oxidation

Why is preferential CO oxidation (PrOX) needed to produce H2 containing less than 10 ppm CO ... 

Would the preferential CO oxidation reaction be needed if the proton-exchange membrane fuel cell (PEMFC) with Pt anode catalyst were able to work at temperatures higher than about 403 K ... 

Preferential Catalytic Oxidation of CO. CO oxidation experiments (O2/CO =1) were conducted in a simulated gas stream of composition CO (9600 ppm) -b H2 (73.36 vol.%) -b CO2 (23.75 vol.%) -b CH4 (1.93 vol.%) (Table 11.7). The Pt catalyst is more active but less selective. The catalysts that contain more Pt were more active. A combination of Pt with Au forming a bimetallic catalyst enables preferential CO oxidation. It should be noted that the Pt-Au-MCM-41 catalysts are not deactivated in CO2. 

TABLE 11.7. Preferential CO oxidation over Au-Pt bimetallic catalysts" ... 

However, in the case of high temperature fuel cells like solid oxide fuel cells (SOFCs) that can utilize CO as a fuel, downstream WGS and preferential CO oxidation are not required and simplify the system. Consider the generalized expression for the POX reaction ... 

The removal of low concentrations of carbon monoxide from the pre-cleaned reformate of hydrocarbon and ethanol reformers is commonly performed by oxidation with air. Owing to the lower carbon monoxide concentration achieved by the low temperatures of methanol reforming, in this case the reformate goes directly to the preferential CO oxidation (PrOx) ... 

Comparison on a Larger Scale Between a Shell and Tube Heat Exchanger, a Porous Metal Structure and a Plate and Fin Heat Exchanger Applied to Preferential CO Oxidation... 

Chapters 7-10 cover the syngas purification and separation. When reforming and water-gas shift are applied to PEMFC systems, trace amounts of CO in the gas that poisons anode catalyst must be removed. This is achieved by preferential CO oxidation, which is covered in Chapter 7 by Marco J. Castaldi of Columbia... 

Kotobuki, M., Watanabe, A., Uchida, H., Yamashita, H., and Watanabe, M. High catalytic performance of Pt-Fe alloy nanoparticles supported in mordenite pores for preferential CO oxidation in H2-rich gas. Applied Catalysis. A, General, 2006, 307, 275. 

Castaldi, M.J., Roychoudhury, S., Boorse, R.S., Karim, H., LaPierre, R., and Pfefferle, W.C. Fuel Processing Session I. In Compact, Lightweight Preferential CO Oxidation (PROX) Reactor Development and Design for PEM Automotive Fuel Cell Applications. Proceedings from the 2003 Spring National Meeting and Process Industries Exposition (ed. AIChE). New Orleans, LA AIChE, March 30-April 3, 2003. 

Srinivas, S., Dhingra, A., Im, H., and Gulari, E. A scalable silicon microreactor for preferential CO oxidation Performance comparison with a tubular packed-bed microreactor. Applied Catalysis. 

It has been demonstrated that catalysts modified by Mn and Fe have higher activity, selectivity and stability in preferential CO oxidation, than the unmodified Au/MgO catalysts [196], The results indicate that the addition of these modifiers changes the type of metal ion-metal nanocluster active sites involved in CO activation, and that the new type of sites are more active above room temperature. 

O. Pozdnyakova, D. Teschner, A. Wootsch, J. Krdhnert, B. Steinhauer, H. Sauer, L. Toth, F. C. Jentoft, A. Knop-Gericke, Z. Paal, R. Schldgl, Preferential CO oxidation in hydrogen (PROX) on ceria-supported catalysts, part I Oxidation state and surface species on Pt/Ce02 under reaction conditions, J. Catal. 237 (2006) 1. 

Opportunities in Catalytic Reaction Engineering. Examples of Heterogeneous Catalysis in Water Remediation and Preferential CO Oxidation... 

Only a year later, compelling experimental evidence that supported the hypothesis that Ag and Cu nanoparticles (<4nm) are active for preferential CO oxidation at low temperature was reported [138]. Although the group of Flytzani-Stephanopoulos [139] had reported that the specific CO oxidation activity of the Cu-Ce-O catalyst was comparable, or even superior, to platinum catalysts back in 1995, presence of Cu nanoparticles as active species had not been proposed. 

Ishida Y, Ebashi T, Ito S, Kubota T, Kunimori K, Tomishige K (2009) Preferential CO oxidation in a Hz-rich stream promoted by ReOx species attached on Pt metal particles. Chem Commun 5308-5310... 

Ebashi T, Ishida Y, Nakagawa Y, Ito S, Kubota T, Tomishige K (2010) Preferential CO oxidation in Hz-rich stream on Pt-ReOx/SiOz catalyst structure and reaction mechanism. J Phys Chem C 114 6518-6526... 

Gorke, O. Pfeifer, P. (2011). Preferential CO oxidation over a platinum oeiia aluminia in a microchannel reactor with distributed gas feeding. International Journal of Hydrogen Energy, Vol. 36, 4673-4681. 

Srinivas, S, Gulari, E. Preferential CO oxidation in a two-stage packed-bed reactor Optimization of oxygen split ratio and evaluation of system robustness. Catal. Common. 2006 7 819-826. 

Preferential CO oxidation has been studied using different noble metals (Pt, Pd, Ru, Rh, and Au) and different supports (silica, alumina, and titania) or over ceria-... 

MOSSBAUER SPECTROSCOPIC INVESTIGATIONS OF NOVEL BIMETAL CATALYSTS FOR PREFERENTIAL CO OXIDATION IN H2... 

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