An Examination of the Catalyst Layer Contribution to the Disparity between the Nernst Potential and Open Circuit Potential in Proton Exchange Membrane Fuel Cells

Abstract

The dependency of the Nernst potential in an operating proton exchange membrane fuel cell (PEMFC) on the temperature, inlet pressure and relative humidity (RH) is examined, highlighting the synergistic dependence of measured open circuit potential (OCP) on all three parameters. An alternative model of the Nernst equation is derived to more appropriately represent the PEMFC system where reactant concentration is instead considered as the activity. Ex situ gas diffusion electrode (GDE) measurements are used to examine the dependency of temperature, electrolyte concentration, catalyst surface area and composition on the measured OCP in the absence of H2 crossover. This is supported by single-cell OCP measurements, wherein RH was also investigated. This contribution provides clarity on the parameters that affect the practically measured OCP as well as highlighting further studies into the effects of catalyst particle surrounding environment on OCP as a promising way of improving PEMFC performance in the low current density regime.

Towards the Reduction of Pt Loading in High Temperature Proton Exchange Membrane Fuel Cells – Effect of Fe−N−C in Pt‐Alloy Cathodes

“…Similar effects were reported by Mardle et al. by comparison of Pt and Pt‐alloy (Ni, Co) catalysts [37] . Further differences in the polarization curves in Figure 2c can be seen in the ohmic region at intermediate (>0.3 A cm −2 ) and at higher current densities (>0.5 A cm −2 ).…”

“…Similar effects were reported by Mardle et al by comparison of Pt and Pt-alloy (Ni, Co) catalysts. [37] Further differences in the polarization curves in Figure 2c can be seen in the ohmic region at intermediate (> 0.3 A cm À 2 ) and at higher current densities (> 0.5 A cm À 2 ). The hybrid MEAs show a drastic decrease in voltage with increasing current density which could be attributed to higher resistances in terms of proton conduction related to acid distribution within the CL.…”

Determination, Manufacturing and application of a nanoparticle lead ion-selective electrode as a sensor in flow injection systems

“…This value is admirable and shows that the theoretical and experimental slopes correspond quite well. (17)(18)(19)(20)(21)(22)(23)(24)(25). The highest initial response (H o ) was recorded after a concentration sample was passed without an injection, and the degree of dispersion was estimated using the equation below (26).…”