Hydrogen-oxygen fuel cells

Fig. 28. Cycle of 34-ceU regenerative hydrogen—oxygen fuel cell where A represents the charging region at 10 A, B represents discharging at 18.2 A. Both (—) voltage and (—) pressure changes are shown. To convert MPa to psig, multiply by 145.

A hydrogen-oxygen fuel cell operates on the reaction ... 

The example of a hydrogen/oxygen fuel cell illustrates this relationship. 

FIGURE L.l One of the three hydrogen-oxygen fuel cells used on the space shuttle to provide life-support electricity and drinking water. 

Major types of hydrogen-oxygen fuel cells broadly developed since about 1960 are the following ... 

The Pt-Rn catalysts have another important property. In contrast to pure platinum, they are almost insensitive to poisoning by carbon monoxide CO. They can be used, therefore, in the hydrogen electrodes of hydrogen-oxygen fuel cells operated with technical hydrogen containing marked amonnts of CO. 

Figure 7.3 A hydrogen-oxygen fuel cell. The water formed at the cathode on the right-hand side of the cell condenses and collects at the bottom of the cell, and drains through a channel at the bottom right-hand side...

Fig. 6-2. Chemical cell and electrolytic cell (a) hydrogen-oxygen fuel cell (chemical cell), (b) water decomposition cell (electrolytic cell).

This reaction of water electrol3 is is the same as, but reverse in its direction to, the reaction of hydrogen-oxygen fuel cell in Eqn. 6-1. Note that the anode and the cathode are reversed in the chemical and the electrolytic cells. 

In 1896, Antonio Henri Becquerel (1852-1908) made a new type of battery and used a carbon rod. Ludwig Mond and Carl Langer produced a gas-powered battery and called their system a fuel cell in 1889. In 1889, Ludwig Mond (1838-1909) and assistant Carl Langer described their experiments with a hydrogen-oxygen fuel cell that attained 6 A (ampere) per square foot at 0.73 V. Mond and Langer s cell used electrodes of thin, perforated platinum. 

Table 1 Thermodynamics Data for the hydrogen-oxygen fuel cell...

Figure 2. Typical potential current curve for the hydrogen-oxygen fuel cell illustrating the different power losses as the current drain increases...

Two half-cells of hydrogen-oxygen fuel cell under basic conditions can be depicted as 0H /02 (g)/ Pt and OHJH2 (g)/... 

The hydrogen-oxygen fuel cell, a Proton Exchange Membrane (PEM)... 

Figure 6.14. Cell Voltage vs. Cell Current profile of a hydrogen - oxygen fuel cell under idealized (dotted-dashed curve) and real conditions. Under real conditions the cell voltage suffers from a severe potential loss (overpotential) mainly due to the activation overpotential associated with the electroreduction process of molecular oxygen at the cathode of the fuel cell. Smaller contributions to the total overpotential losses (resistance loss and mass transport) are indicated.

Figure 15.9 Voltage-current relationship for a typical hydrogen-oxygen fuel cell. The vertical separation between the anode and cathode curves represents the cell output voltage.

Figure 15.10 Hydrogen/oxygen fuel cell voltage and efficiency as a function of the current drawn.

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