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Fuels - Hydrogen Fuel Cell.

What is a Fuel Cell?

A fuel cell is not the same as a battery.
A fuel cell needs to be continuously supplied with both a fuel
and oxygen, which react together and produce electricity.

When the fuel being used is hydrogen
the fuel cell produces electricity plus water.


What is a Hydrogen Fuel Cell?

A hydrogen fuel cell is made from an anode and a cathode
with an electrolyte contained between them.
The fuel cell generates electricity. It is not the same as an
electrolysis cell which needs to be supplied with electricity.

Hydrogen Fuel Cell

The electrolyte in an alkali fuel cell is potassium hydroxide (KOH).

The anode is a platinum catalyst. Hydrogen is supplied to
the anode and it reacts with hydroxide ions from the
electrolyte to make water. This is an oxidation reaction
in which electrons are lost from hydrogen. The electrons
leave the anode and travel through the external circuit
which is using the electricity that is supplied by the fuel cell.

The cathode is also a platinum catalyst. Oxygen supplied to
the cathode reacts with water and gains electrons to make
hydroxide ions in the electrolyte. This is a reduction reaction.

The overall reaction in the fuel cell is

hydrogen + oxygen  arrow  water + energy
2H2(g)   +    O2(g)  arrow          2H2O(l)

The electricity provided by the fuel cell can be used
to run an electric vehicle or to power other equipment.


 What are the Advantages of a Hydrogen Fuel Cell?

1.  It can be a renewable source of electricity if
the hydrogen comes from a renewable resource.
See the advantages of hydrogen as a fuel.

2.  It does not produce pollution or contribute
to global warming because the only product is water.


What are the Disadvantages of a Hydrogen Fuel Cell?

1.  Each fuel cell only makes a small voltage.
A large number of fuel cells must be wired together to
produce a large voltage or current. This is expensive.

2.  Hydrogen is explosive and difficult to store.

3.  If the hydrogen does not come from a renewable
resource but is made from methane, then the electricity
produced from the fuel cell is also not renewable.

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