Hydrogen-car

So-called fuel cell (and should be called "hydrogen cell") consists of an anode made of a metal with high corrosion resistance, like aluminum, copper or inox, covered by the colloidal platinum which works as a catalyst. Electrodes have usually wavy shape or they form a grid, for example 0.5x0.5 mm. Between electrodes a thin (0.12-0.25 mm) polymeric membrane is placed, working as a sieve for protons. Platinum assures dissociation of the molecular hydrogen into a proton and electron, according to the scheme:

Protons migrate through the membrane (which is transparent only to them) to the cathode and electrons are captured by the anode and then move to the external electric circuit. On the cathode they are captured by protons and the water molecule is formed with oxygen.

In sum, oxygen is supplied to the cathode region and hydrogen to the anode one and water is produced as a result of the reaction. (A layer of colloidal platinum is placed also on the cathode).

On the cathode, there is also a thin layer of platinum (catalyst). Water is a byproduct of the cell's operation.

Other types of membranes (for example ceramic ones, working at high temperatures) and other types of reactions can be also used in fuel cells. The picture shows Proton Exchange Membrane Fuel Cell. The efficiency of such a cell is about 0.5 to 2 W for 1 cm2, the voltage is 0,5 to 1 V and the current up to 2 A from 1 cm2 of the cell.

The cell is packed in a hermetic plastic box and the current is collected form the external electrodes.

The efficiency of such a cell is about 0.5 to 2 W for 1 cm², the voltage is 0,5 to 1 V and the current up to 2 A from 1 cm² of the cell.

A massive use of fuel cells in transportation and energy production would reduce the emission of CO2 by 40% - 60%, and the emission of nitrogen oxides by 50% -90%.