PEMFC exchange membrane fuel cell

The most promising fuel cell for transportation purposes was initially developed in the 1960s and is called the proton-exchange membrane fuel cell (PEMFC). Compared with the PAFC, it has much greater power density state-of-the-art PEMFC stacks can produce in excess of 1 kWA. It is also potentially less expensive and, because it uses a thin solid polymer electrolyte sheet, it has relatively few sealing and corrosion issues and no problems associated tvith electrolyte dilution by the product water. 

Proton Exchange Membrane Fuel Cells (PEMFCs)... 

Propylene glycol, glycolysis of polyurethanes with, 572 Propylene oxide (PO), glycolysis of polyurethanes with, 572-573 Propylene oxide (PO) polyols, 211, 223 Proton exchange membrane fuel cells (PEMFCs), 272-273 Proton NMR integrations, 386. See also H NMR spectroscopy Protonic acids, reactions catalyzed by, 67-68... 

PEMFC proton exchange membrane fuel cell... 

Membrane-type fuel cells. The electrolyte is a polymeric ion-exchange membrane the working temperatures are 60 to 100°C. Such systems were first used in Gemini spaceships. These fuel cells subsequently saw a rather broad development and are known as (solid) polymer electrolyte or proton-exchange membrane fuel cells (PEMFCs). 

Significant (and even spectacular) results were contributed by the group of Norskov to the field of electrocatalysis [102-105]. Theoretical calculations led to the design of novel nanoparticulate anode catalysts for proton exchange membrane fuel cells (PEMFC) which are composed of trimetallic systems where which PtRu is alloyed with a third, non-noble metal such as Co, Ni, or W. Remarkably, the activity trends observed experimentally when using Pt-, PtRu-, PtRuNi-, and PtRuCo electrocatalysts corresponded exactly with the theoretical predictions (cf. Figure 5(a) and (b)) [102]. 

Ambient temperature catalysis of O2 reduction at low overpotentials is a challenge in development of conventional proton exchange membrane fuel cells (pol5mer electrolyte membrane fuel cells, PEMFCs) [Ralph and Hogarth, 2002]. In this chapter, we discuss two classes of enz5mes that catalyze the complete reduction of O2 to H2O multi-copper oxidases and heme iron-containing quinol oxidases. 

There are six different types of fuel cells (Table 1.6) (1) alkaline fuel cell (AFC), (2) direct methanol fuel cell (DMFC), (3) molten carbonate fuel cell (MCFC), (4) phosphoric acid fuel cell (PAFC), (5) proton exchange membrane fuel cell (PEMFC), and (6) the solid oxide fuel cell (SOFC). They all differ in applications, operating temperatures, cost, and efficiency. 

Proton Exchange Membrane Fuel Cells (PEMFCs) are being considered as a potential alternative energy conversion device for mobile power applications. Since the electrolyte of a PEM fuel cell can function at low temperatures (typically at 80 °C), PEMFCs are unique from the other commercially viable types of fuel cells. Moreover, the electrolyte membrane and other cell components can be manufactured very thin, allowing for high power production to be achieved within a small volume of space. Thus, the combination of small size and fast start-up makes PEMFCs an excellent candidate for use in mobile power applications, such as laptop computers, cell phones, and automobiles. 

Proton exchange membrane fuel cells (PEMFC), 72 201, 211-213 73 861-862... 

This survey focuses on recent developments in catalysts for phosphoric acid fuel cells (PAFC), proton-exchange membrane fuel cells (PEMFC), and the direct methanol fuel cell (DMFC). In PAFC, operating at 160-220°C, orthophosphoric acid is used as the electrolyte, the anode catalyst is Pt and the cathode can be a bimetallic system like Pt/Cr/Co. For this purpose, a bimetallic colloidal precursor of the composition Pt50Co30Cr20 (size 3.8 nm) was prepared by the co-reduction of the corresponding metal salts [184-186], From XRD analysis, the bimetallic particles were found alloyed in an ordered fct-structure. The elecbocatalytic performance in a standard half-cell was compared with an industrial standard catalyst (bimetallic crystallites of 5.7 nm size) manufactured by co-precipitation and subsequent annealing to 900°C. The advantage of the bimetallic colloid catalysts lies in its improved durability, which is essential for PAFC applicabons. After 22 h it was found that the potential had decayed by less than 10 mV [187],... 

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 ... 

All fuel cells for use in vehicles are based on proton-exchange-membrane fuel cell (PEMFC) technology. The methanol fuel-processor fuel cell (FPFC) vehicle comprises an on-board fuel processor with downstream PEMFC. On-board methanol reforming was a development focus of industry for a number of years until around 2002. Direct-methanol fuel cells (DMFC) are no longer considered for the propulsion of commercial vehicles in the industry (see also Chapter 13). 

PAFC PEMFC PFC PGM PHEV PISI PM POX ppm PPP Phosphoric-acid fuel cell Proton-exchange-membrane fuel cell Polymer-electrolyte membrane Perfluorocarbons Platinum-group metals Plug-in hybrid-electric vehicle Port-injection spark ignition Particulate matter Partial oxidation Parts per million Purchasing power parity... 

Fig. 14.12 Principle of a proton exchange membrane fuel cell (PEMFC).

The PEMFC (Proton Exchange Membrane Fuel Cell) is a fuel cell with a protonconducting fluorinated polymer as electrolyte. Figure 14.12 gives a schematic drawing of the PEMFC. At the anode, hydrogen is oxidized to protons. At the cathode, oxygen from air is reduced to water. The PEMFC is in development for various applications. 

Gamburzev, S., and Appleby, A. J. Recent progress in performance improvement of the proton exchange membrane fuel cell (PEMFC). Journal of Power Sources 2002 107 5-12. 

Because of its lower temperature and special polymer electrolyte membrane, the proton exchange membrane fuel cell (PEMFC) is well-suited for transportation, portable, and micro fuel cell applications. But the performance of these fuel cells critically depends on the materials used for the various cell components. Durability, water management, and reducing catalyst poisoning are important factors when selecting PEMFC materials. 

Proton exchange membrane fuel cells (PEMFCs) work with a polymer electrolyte in the form of a thin, permeable sheet. The PEMFCs, otherwise known as polymer electrolyte fuel cells (PEFC), are of particular importance for the use in mobile and small/medium-sized stationary applications (Pehnt, 2001). The PEM fuel cells are considered to be the most promising fuel cell for power generation (Kazim, 2000). 

Obviously, in practical situations one can hardly imagine a vacuum pump installed onboard of a fuel cell-powered vehicle. Even if so, the membrane of a Proton Exchange Membrane Fuel Cell (PEMFC) will be soon contaminated by the oil vapors released from the pump (dry pumps are possible but this would enormously complicate the entire design). 

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