Hydrocarbon proton exchange membrane

Hydrogen as the most efficient and cleanest energy source for fuel-cell power is produced by partial oxidation followed by the water gas-shift reaction and reforming of hydrocarbons or methanol [58]. A small amount of CO (0.3-1%) in the so-produced H2 must be selectively removed because CO greatly poisons Pt/C and Pt-M/C electrocatalysts in proton-exchange-membrane (PEM) fuel cells [59, 60]. PROX of CO in excess H2 is a key reaction in the practical use of H2 in PEM fuel-cell systems. 

An important possible future use for pure hydrogen is in proton-exchange-membrane fuel cells (PEMFCs) the basic source for the hydrogen could be either a hydrocarbon or an alcohol, either of which can be steam-reformed to produce water-gas.16,17 As explained above, the equilibrium concentration of carbon monoxide decreases as the temperature falls (Figure 10.1), but as little as 1% is detrimental to the operation of platinum-based catalysts in a fuel cell. Excess water, which is commonly used,18 serves to move the... 

The bicontinuous-microemulsion polymerization technique has also been used to develop novel proton exchange membranes (PEM) for fuel cell evaluation [97]. A series of hydrocarbon-based membranes were prepared based on the formulation shown in Fig. 5, with additional ionic vinyl monomers such as VB-SLi or bis-3-sulfopropyl-itaconic acid ester. After polymerization, the membranes were treated with dilute H2SO4 (0.5 M) to convert them to PEM membranes. The good performance of these PEM membranes in a single fuel cell is illustrated in Fig. 9. 

Related work includes investigations of carbon formation during hydrogenation of C5 hydrocarbons catalyzed by nickel and palladium (5P) interactions of N2O with a hydrotalcite-derived multimetallic mixed oxide catalysts (60,61) changes in mass of solid oxides (62) methanol sorption in Nafion-117 (proton-exchange) membranes (63) vanadyl pyrophosphate catalysts for butane oxidation (64-66) and deactivation/regeneration of a Rb0 c/Si02 catalyst for methylene valerolactone synthesis (67). 

In fuel cells systems, as reported in recent patents [13,14], membranes wUl be present not only as PEM (proton-exchange membrane), which allows protons to pass from the anode to the cathode where they are combined with oxygen and electrons to produce water, but also for the production and purification of the H2 (Figure 43.3). This system provides a C02-selective membrane process for the purification and water gas shift reaction of a reformed gas, generated from on-board reforming of a fuel, e.g., hydrocarbon, gasoline, diesel, methanol, or natural gas, to hydrogen for fuel cell vehicles. 

C.H. Park, C.H. Lee, M.D. Guiver, Y.M. Lee, Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs). Progress in Polymer Science 2011, 36(11), 1443-1498. 

Gross M, Maier G, Fuller T, MacKinnon S and Gittleman C S (2009), Design rules for the improvement of the performance of hydrocarbon-based membranes for proton exchange membrane fuel cells (PEMFC) , in Handbook of Fuel Cells, Vol. 5 (W. Vielstich, H. Yokokawa, and H. A. Gasteiger, eds.),Wiley. 

FIG U RE 5.22 NMR cryoporometric melting curves for the specific pore volume related to the corresponding radius R. (Adapted from von Kraemer, S., Sagidullin, A.I., Lindbergh, G., Furo, 1., Persson, E., and Jannasch, P. Pore size distribntion and water nptake in hydrocarbon and perfluorinated proton-exchange membranes as studied by NMR cryoporometry. Fuel Cells. 2008. 8. 262-269. Copyright 2008 WUey-VCH... 

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