Polarization curve at different temperatures

FIG. 24-53 Polarization curves at different temperatures for 50-cm active length thin-wall SOFCs. 

Figure 1. Polarization Curve at Different Temperatures and Platinum Loadings at 3 Atmospheres and with 3.5 nanometer Catalyst Particle Size...

Figure 29. Polarization and power density curves at different temperatures of an active DMFC with a Pd/MWCNT anode (Pd loading 1 mg cm ), fuelled with an aqueous 2 M KOH solution of methanol (10 wt%). The inset reports the temperatures of fuel (left), cell (central), oxygen gas (right). Reprinted from Ref. 29, Copyright (2009) with permission from Elsevier.

Fig. 2.25 Steady-state polarization curves at different humidification is observed at high current densities and relative humidities for high temperature polymer electro- low RH. Reproduced from [32] with permission of the lyte fuel cell based on Aquivion (Solvay) membrane American Chemical Society and CNR-ITAE catalysts. The effect of internal...

The range of the isovolatility curves can be extended by extrapolation through mathematical procedures, by injections at different temperature programming rates [12] or by use of the more polar homologous series (2-methylketones and fatty acids methyl esters [11], alcohols [12]) instead of the n-alkanes. 

Fig. 17. Time evolution of the NMR signal from hydroxyl protons of silica Aerosil 300 in contact with optically polarized xenon at a temperature of 135 K. HP xenon with both positive and negative polarizations was used to generate the two different curves. (Reprinted from ref 266 with permission. Copyright 1998, Academic Press.)...

Figure 6.13. (a), (b) Experimental voltage current curves at different points along a single flow channel (1 mmx 1 mm cross section) on the cathode side of a fuel cell, for an air flow rate of (a) 20 seem and (b) 50 seem. Hydrogen flow rate on anode of 25 seem. Cell temperature of 30°C. Dimensionless distanees along the ehannel are listed below eaeh eurve. Dotted line, average eell performanee. (e) Theoretieal loeal polarization eurves for indieated dimensionless distances from the channel inlet. 

The influence of CO poisoning at the anode of an HT-PEFC was investigated by Bergmann et ul. [28]. The dynamic, nonisothermal model takes the catalyst layer as a two-dimensional plane between the membrane and gas diffusion layer into account. The effects of CO and hydrogen adsorption with respect to temperature and time are discussed in detail. The CO poisoning is analyzed with polarization curves for different CO concentrations and dynamic CO pulses. The analysis of fuel-cell performance under the influence of CO shows a nonlinear behavior. The presence of water at the anode is explicitly considered to take part in the electrooxidation of CO. The investigation of the current response to a CO pulse of 1.31% at the anode inlet showed a reversible recovery time of 20 min. 

Fig. 16.3 Cyclic voltaimnograms (a) for a W2N/C (43 mg W2N) in the 0.5 M H2SO4 solution saturated with nitrogen (1) and oxygen (2), respectively. For reasons of comparison, the linear scan of a 20% Pt/C catalyst (12 mg Pt) in oxygen-saturated solution is given (3), all measurements were performed with a scan rate of 5 mV s and at T = 25°C. hr (b), polarization curves as obtained at different temperatures using a W2N/C catalyst (18% W) as cathode material are shown. Figures were taken from [33], reproduced with permission of Elsevier...

Fig. 21.8 Polarization curve of BASF HTPEM Celtec MEA at different temperatures and different CO concentrations...

Fig. 21.10 Polarization curve using pure hydrogen at different temperatures [56]...

If these four equations are substituted into Eqns (9.14), (9.9), and (9.12), a semiempitical equation can be obtained, from which the fuel cell polarization curve can be calculated at a desired temperature, backpressure (obtained using gas partial pressure, according to Eqn (9.9) or (9.12)), and RH. Figure 9.2 shows the calculated polarization curves at two different backpressures (2.0 and 3.0 atm absolute backpressure, respectively). Evidently, the backpressure has an effect on performance. Note that during calculation, the values of both and / m were measured from their... 

Fig. 39. Anodic charging curves on platinized platinum with 50 mA in O.5MH2SO4 at different temperatures. Chemisorbed species formed previously by bubbling with CO for curves a, b, c, d and by anodic polarization in 0.5M H2SO4 + O.IM CH3OH for curves...

V for H2/O2 PEMFC and down to around 0.6 V for DMFC. The PEMFC (Figure 8.3) and SOFC (Figure 8.4) polarization curves at low current densities are quite different due to significant temperature dependence of the charge transfer reaction. At elevated temperatures, the electron transfer reaction is much faster, and therefore, the charge transfer resistance is much smaller. As a result, the experimental and theoretical (0.977 V) OCPs at 800°C are very close. 

Figure 4.19 Typical polarization curves for high-temperature SOFC in different gas environments at 1000° C. The high operating temperature enables the use of low-cost catalyst materials such as nickel (anode) and strontium-doped lanthanum manganite (cathode), with very low kinetic polarization losses. (Reproduced with permission from [5].)...

Fig. 14.14 Polarization (a) and power density (b) curves of Pt supported on CMK-3 catalysts with different surface chemistry at the anode side of a PEFC working at room temperature and atmospheric pressure (Reprinted from [149] with permission from Elsevier).

Fig. 14.20 Fuel cell polarization curves for CM-FeS04-KB (cyanamide-FeS04-Ketjeblack) ORR catalysts obtained at different heat-treatment temperatures. Operating conditions H2/02,100% RH,...

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