ORR kinetics

The quantitative evaluation of the effects of adsorbed species on the ORR kinetics was obtained from the following equation ... 

The experiments showed that the properties of the Pt monolayer were modified differently by the different supporting metal (Fig. 9.13). PtML/Pd(lll) and PIml/ Ru(OOOl) are the most and least active of these surfaces, respectively. When the ORR kinetic currents obtained from Koutecky-Levich plots are plotted against the... 

Thin catalyst layers on a GC rotating disk electrode (RDE) or a rotating ring-disk electrode (RRDE) serve for studies of ORR kinetics. In order to separate the kinetic current from the measured current j, Schmidt and co-workers [Schmidt et al., 1998b] corrected the latter for the influence of oxygen diffusion in the aqueous electrolyte and in the polymer film using the foUowing equation ... 

Detailed investigation of ORR kinetics at subzero temperature was first reported by Thompson et al.9 Fig. 8 shows the Tafel plots measured at -20°C with various membrane water content. At high... 

Detailed investigation of ORR kinetics under subzero temperature showed that the fundamental ORR kinetic mechanism remains unchanged over a wide temperature range down to -40°C. The low-temperature CV detected the loss of cathode catalyst electrochemical active area during cold start, part of which was recovered at room temperature, while others were not recovered until higher temperature ( 70°C) operation. 

MEA performance is mainly limited by ORR kinetics, as well as oxygen transport to the cathode catalyst. Another major loss is due to proton conduction, in both the membrane and the cathode catalyst layer (CL). Characterization of the ionic resistance of fuel cell electrodes helps provide important information on electrode structure optimization, and quantification of the ionomer degradation in the electrodes [23],... 

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