Water-gas shift low temperature

The attention given to the causes and control of catalyst die-off in industry is well illustrated by the behavior of different formulations of Cu-ZnO-AhOs catalysts for the low temperature water gas shift reaction. 

The low temperature water-gas shift reaction is well described by a micro-kinetic model [C.V. Ovesen, B.S. Clausen, B.S. Hammershoj, G. Sreffensen, T. Askgaard, I. Chorkendorffi J.K. Norskov, P.B. Rasmussen, P. Stoltze and P.J. Taylor,/. Catal. 158 (1996) 170] and follows to a large extent the scheme in Eqs. (23-31). The analysis revealed that formate may actually be present in nonvanishing amounts at high pressure (Fig. 8.18). 

While the above results appear to strongly favor a surface formate associative mechanism for low-temperature water-gas shift over the Pt/Zr02 catalysts, methods to provide direct support for the mechanism have remained elusive. 

Pigos, J.M., Brooks, C.J., Jacobs, G., and Davis, B.H. 2007. Low temperature water-gas shift Characterization of Pt-based Zr02 catalyst promoted with Na discovered by combinatorial methods. Appl. Catal. A Gen. 319 47-57. 

Li, Y., Fu, Q., and Flytzani-Stephanopoulos, M. 2000. Low-temperature water-gas shift reaction over Cu- and Ni-loaded cerium oxide catalysts. Appl. Catal. B Environ. 27 179-91. 

Andreeva, D., Idakiev, V., Tabakova, T., Ilieva, L., Falaras, P., Bourlinos, A., and Travlos, A. 2002. Low-temperature water-gas shift reaction over Au/Ce02 catalysts. Catal. Today 72 51-57. 

Jacobs, G., Graham, U.M., Chenu, E., Patterson, P.M., Dozier, A., and Davis, B.H. 2005. Low-temperature water-gas shift Impact of Pt promoter loading on the partial reduction of ceria and consequences for catalyst design. J. Catal. 229 499-512. 

Leppelt, R., Schumacher, B., Plzak, V., Kinne, M., and Behm, R.J. 2006. Kinetics and mechanism of the low-temperature water-gas shift reaction on Au/Ce02 catalysts in an idealized reaction atmosphere. J. Catal. 244 137-52. 

Sakurai, H., Ueda, A., Kobayashi, T., and Haruta, M. 1997. Low-temperature water-gas shift reaction over gold deposited on Ti02. Chem. Commun. 271. 

Andreeva, D. Ch., Idakiev, V.D., Tabakova, T.T., and Giovanoli, R. 1998. Low-temperature water-gas shift reaction on Au/Ti02, Au/a-Fe203 and Au/Co304 catalysts. Bulg. Chem. Commun. 30 59-68. 

Boccuzzi, F., Chiorino, A., Manzoli, M., Andreeva, D., and Tabakova, T. 1999. FTIR study of the low-temperature water-gas shift reaction on Au/Fe203 and Au/Ti02 catalysts. J. Catal. 188 176-85. 

Venugopal, A., Aluha, J., Mogano, D., and Scurrell, M.S. 2003. The gold-ruthe-nium-iron oxide catalytic system for the low temperature water-gas-shift reaction The examination of gold-ruthenium interactions. Appl. Catal. A Gen. 245 149-58. 

The book focuses on three main themes catalyst preparation and activation, reaction mechanism, and process-related topics. A panel of expert contributors discusses synthesis of catalysts, carbon nanomaterials, nitric oxide calcinations, the influence of carbon, catalytic performance issues, chelating agents, and Cu and alkali promoters. They also explore Co/silica catalysts, thermodynamic control, the Two Alpha model, co-feeding experiments, internal diffusion limitations. Fe-LTFT selectivity, and the effect of co-fed water. Lastly, the book examines cross-flow filtration, kinetic studies, reduction of CO emissions, syncrude, and low-temperature water-gas shift. 

Chapter 19 Low-Temperature Water-Gas Shift Assessing Formates as Potential Intermediates over Pt/Zr02 and Na-Doped Pt/Zr02 Catalysts Employing the SSITKA-DRIFTS Technique.365... 

Especially for the low temperature water gas shift reaction the mechanistic scheme, proposed here, seems to correspond to the three different adsorbed oxygen species, proposed by Kobaya-shi (13) for the ethylene oxidation on silver, whereas the importance of some surface complexes of CO - 1 0 type has been revealed (14) by analysing steady state data. 

Gary Jacobs and Burt Davis (University of Kentucky) review catalysts used for low-temperature water gas shift, one of the key steps in fuel processors designed to convert liquid fuels into hydrogen-rich gas streams for fuel cells. These catalysts must closely approach the favorable equilibrium associated with low temperatures, but be active enough to minimize reactor volume. The authors discuss both heterogeneous and homogeneous catalysts for this reaction, with the latter including bases and metal carbonyls. 

---