Performance Study of a Fuel Cell Pt‐on‐C Anode in Presence of  CO  and  CO 2, and Calculation of Adsorption Parameters for  CO  Poisoning

Abstract

A study was undertaken to measure polarization losses due to the presence of CO2 and CO in the H2 fuel for a practical fuel cell Pt/C anode. A porous Pt anode (0.3 mg/cm2 Pt) was tested as a floating electrode in a half‐cell assembly to measure performance in 100 weight percent H3PO4 at 190°C in presence of H2 , and H2 , CO2 , and CO gas mixtures. The additional polarization loss over that of H2 due to CO2 dilution followed closely the expected loss from the Nernst equation in the range of current density 0–300 mA/cm2. The combined loss due to poisoning by CO and the dilution by CO and CO2 was analyzed and found to be additive of the poisoning and dilution losses. The poisoning loss by CO was calculated by subtracting the dilution loss from the combined dilution and poisoning loss. Such data were found to be linearly dependent on the logarithm of false[COfalse]/false[H2false] ratio. This is consistent with CO poisoning by replacement of H2 sites on the porous Pt electrode. The calculated values of surface coverage by CO ranged from 0.089 to 0.31 as the ratio false[COfalse]/false[H2false] varied from 0.01 to 0.025. The values of surface coverage were consistent with the dual site elimination model for the replacement of H2 by CO molecules. The exchange current densities for H2 oxidation varied from 309 to 142 mA/cm2 as the ratio false[COfalse]/false[H2false] changed from 0 to 0.025. By comparing the experimental isotherm for CO adsorption with the Temkin isotherm, the interaction parameter was calculated to be 3.83 kcal/mol, and the standard free energy of adsorption, −10.96 kcal/mol. The latter value indicated an adsorption of CO which is comparable to H2 .

Modelling of CO Poisoning and its Dynamics in HTPEM Fuel Cells

“…The effect of CO poisoning of low temperature PEM fuel cells has been published by Baschuk et al [12] focussing on the anode processes regarding hydrogen and carbon monoxide. Dhar et al [13,14] published an analytical model of CO poisoning in PEM fuel cells at higher temperatures. Korsgaard et al developed semi-empirical models of HTPEM fuel cells examining the influences of gas feeding on commercially available MEA [15] and CO poisoning in this simplified way, taking adsorption/desorption processes for CO into account [16].…”

AC Impedance Spectroscopy Measured on Different Precious Metals-Electrolyte Interfaces Used for Methanol Fuel Cells by Mean of Two Theoretical Models

“…Yf Zf [40] Where: [46] E I Rct f 1 [47] CO f I m 1 [48] OH f I m 2 [49] ECS Transactions, 11 (32) 127-150 (2008)…”

Experimental performance evaluation of a combustion heat-assisted catalytic flat plate fuel reformer for fuel cell grade hydrogen

“…The only issue of using reformate fuel into the PEMFC stack is to degradation of PEMFC stack performance due to poisoning of Pt catalyst, used in PEMFC, by the carbon 4 monoxide (CO) presence in the reformate fuel [1][2]. Recently, development of temperature resistant high conductive polymer membranes, such as the acid-doped polybenzimidazole (PBI) membranes [2,[18][19][20], open up the opportunity to build high temperature PEM fuel cell (HTPEMFC) stack which can be fed with lower quality (i.e. higher CO concentrations in hydrogen) reformate hydrogen [2,[18][19][20] directly from the fuel reformer.…”

“…Recently, development of temperature resistant high conductive polymer membranes, such as the acid-doped polybenzimidazole (PBI) membranes [2,[18][19][20], open up the opportunity to build high temperature PEM fuel cell (HTPEMFC) stack which can be fed with lower quality (i.e. higher CO concentrations in hydrogen) reformate hydrogen [2,[18][19][20] directly from the fuel reformer. From the thermodynamics point of view, the high operational temperature makes it possible to improve the CO tolerance in HTPEMFC stack at a higher level [2,[18][19][20].…”

“…higher CO concentrations in hydrogen) reformate hydrogen [2,[18][19][20] directly from the fuel reformer. From the thermodynamics point of view, the high operational temperature makes it possible to improve the CO tolerance in HTPEMFC stack at a higher level [2,[18][19][20]. Hydrogen-rich reformate can be produced on-board by reforming process using hydrocarbon fuels available at the nationwide refueling stations [5][6][21][22][23][24][25][26][27][28][29].…”