AFCs suffer a drastic performance loss with fuels containing CO2 from reformed fuels, and from the presence of CO2 in air (approximately 350 ppm CO2 in ambient air). The negative impact of CO2 arises from its reaction with OH ;
producing the following effects: 1) reduced OH concentration interfering with kinetics, 2) electrolyte viscosity increase resulting in lower diffusion rate and lower limiting currents, 3) precipitation of carbonate salts in the pores of the porous electrode, 4) reduced oxygen solubility, and 5) reduced electrolyte conductivity. The influence of CO2 on air cathodes (0.2 mg Pt/cm supported on carbon black) in 6 N KOH at 50oC can be ascertained by analysis of the performance data presented in Figure 4-6 (21). To obtain these data, the air electrodes were operated continuously at 32 mA/cm2, and current-voltage performance curves were periodically measured. Performance in both CO2 free air and CO2 containing air show evidence of degradation with time. However, with CO2 free air the performance remains much more nearly constant with 2000 to 3000 hour operation.
0 1000 2000 3000
Was this article helpful?
Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.