The Hydrogen-Oxygen Fuel Cell

Hydrogen (the fuel) is supplied to the anode compartment. Oxygen is fed into the cathode compartment. The diffusion rates of the gases into the cell are carefully regulated for maximum efficiency. Oxygen is reduced at the cathode, which consists of porous carbon impregnated with a finely divided Pt or Pd catalyst. 

Nickel-melal-lqdriile batterytedinok is used in hybrid gas-eiectric vehicies such as the Ford Escape Hybrid. The NMH batteries (330-von) are used to power the eiectric drive motor in the transmission. The batteries are recharged when brakes are appiied via regenerative brakiiqt. 

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The OH ions migrate through the electrol)rte to the anode, an aqueous solution of a base. The anode is also porous carbon containing a small amount of catalyst (Pt, Ag, or CoO). Here H2 is oxidized to H2O. 

The net reaction is the same as the burning of H2 in O2 to form H2O, but combustion does not actually occur. Most of the chemical energy from the formation of H—O bonds is converted directly into electrical energy, rather than into heat energy as in combustion. When the H2/O2 fuel cell is used aboard spacecraft, it is operated at a high enough i temperature that the water evaporates at the same rate as it is produced. The vapor is then condensed to pure water. i 

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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...

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

Was this your answer During electrolysis, electrical energy is used to produce chemical change. In the hydrogen-oxygen fuel cell, chemical change is used to produce electrical energy. Therefore, the answer to the question is no. 

Using the standard free energies of formation in Appendix B, calculate the standard cell potential for the reaction in the hydrogen-oxygen fuel cell ... 

William Grove (English) Grove discovered "reverse electrolysis" following electrolysis of water at platinum electrodes proposed the hydrogen-oxygen fuel cell. 

The evaluation of ILs as electrolytes for fuel cell has already been done. Wata-nabe et al. tested the power generation of the hydrogen/oxygen fuel cell by using a... 

For the hydrogen-oxygen fuel cell considered above, the enthalpy change during the two processes (3.15) and (3.16) (in the direction left to right) is AH = -9.5 X 10 J or -2.86 x 10 J per mole of H2O formed, and the ideal efficiency of power production in this case is thus... 

The hydrogen-oxygen fuel cell also burns hydrogen in a sense, but the burning is controlled so that most of the chemical energy is converted to electrical energy, not to heat. 

Calculating Use data from Table 21-1 to calculate the cell potential of the hydrogen-oxygen fuel cell described in this section. 

Fuel cells are voltaic cells in which the reactants are continuously supplied to the cell and the products are continuously removed. The hydrogen-oxygen fuel cell (Figure 21-17) already has many applications. It is used in spacecraft to supplement the energy obtained from solar cells. Liquid H2 is carried on board as a propellant. The boiled-off H2 vapor that ordinarily would be lost is used in a fuel cell to generate electrical power. 

Sketch and describe the operation of (a) the Leclanche dry cell, (b) the lead storage battery, and (c) the hydrogen-oxygen fuel cell. 

Perfluorinated polyethers have also gained importance as actively functional materials. Ionic polymer membranes (e.g. DuPont s Nafion ) based on sulfonic acid-derivatized perfluoropolyethers have been used for nearly 30 years as ion-con-ducting membranes in chloralkali electrolysis cells, replacing the large amounts of toxic mercury used until then in the classic Castner-Kellner cells (Scheme 4.8.). One of the earliest applications of Nafion was as a membrane in the hydrogen-oxygen fuel cells which powered the Apollo spacecraft carrying the first men to the moon. 

The hydrogen-oxygen fuel cell is described in Section 19.6. (a) What volume of H2(.g), stored at 25°C at a pressure of 155 atm, would be needed to... 

The anodic reaction, represented by the reverse of Eq. (129), is of even greater significance. It is one of the half cell reactions in the hydrogen-oxygen fuel cell—the most highly developed fuel cell. 

The hydrogen-oxygen fuel cell has a standard emf of 1.23 V. What advantages and disadvantages there to using this device as a source of power compared to a 1.55-V alkaline battery ... 

LAYOUT OF A REAL FUEL CELL THE HYDROGEN-OXYGEN FUEL CELL WITH LIQUID ELECTROLYTE... 

As an example of areal fuel cell, therefore, we consider the hydrogen-oxygen fuel cell with an aqueous acid electrolyte and its special features. The special features of other types of fuel cells are described in the following chapters. 

The electrochemical reactions occurring at the electrodes of polymer electrolyte membrane fuel cells, as well as the overall current-producing reaction are the same as in the hydrogen-oxygen fuel cells with liquid acidic electrolyte discussed in Section 16.4 (Eqs. 16.2 and 16.3). 

At present, most of the work toward building methanol fuel cells relies on technical and design principles, developed previously for polymer electrolyte membrane fuel cells. In both kinds of fuel cells, it is common to use platinum-ruthenium catalysts at the anode and a catalyst of pure platinum at the cathode. In the direct methanol fuel cells, the membrane commonly used is of the same type as in the hydrogen-oxygen fuel cells. The basic differences between these versions are discussed in Section 19.7. 

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