A hydrogen car is one that uses the gas hydrogen as a fuel source. There are basically two ways in which hydrogen is used:
1. Hydrogen is converted to electricity through the process of hydrolysis, powering electric motors driving the car along. (SEE BELOW)
2. A conventional engine burns combustible hydrogen gas in the place of diesel or petrol. An adapted car engine drives the wheels around propelling the vehicle forwards/backwards.

A major advantage of the hydrogen powered vehicles named above is that the only by-product is water.

THE HYDROGEN FUEL CELL

A fuel cell is an essential part of a hydrogen car producing electricity to drive motors. It consists of three parts - the ANODE, CATHODE and CATALYST.
Hydrogen is fed under pressure into the ANODE where it produces electrons and they are conducted through the ANODE and around the external circuit driving the motors. Water is the only by-product and this is produced at the CATHODE.
One fuel cell is not enough to produce meaningful power, so cells are arranged in stacks
The CATALYST is essential as it starts the chemical reactions necessary to ‘free, electrons, creating electricity.