What is the role of oxygen in hydrogen fuel cells?

Oxygen in hydrogen fuel cells combines with hydrogen to produce water, releasing energy in the process.

In a hydrogen fuel cell, oxygen plays a crucial role in the electrochemical reaction that generates electricity. The basic operation of a hydrogen fuel cell involves two key reactions. On the anode side, hydrogen gas (H2) is split into two hydrogen ions (H+) and two electrons (e-). These electrons are then conducted through an external circuit, creating an electric current.

Meanwhile, on the cathode side, oxygen gas (O2) is introduced. The oxygen molecules react with the hydrogen ions and the electrons that have travelled through the external circuit. This reaction produces water (H2O), which is the only by-product of a hydrogen fuel cell. The combination of hydrogen and oxygen to produce water is an exothermic reaction, meaning it releases energy. This energy is harnessed as electrical power.

The role of oxygen is therefore twofold: it combines with hydrogen to produce water, and in doing so, it facilitates the release of energy that can be used to power electrical devices. Without the presence of oxygen, the electrochemical reaction in a hydrogen fuel cell would not occur, and no electricity would be generated.

In summary, oxygen is a vital component in the operation of hydrogen fuel cells. It not only helps to produce a harmless by-product (water), but also enables the generation of electricity. This makes hydrogen fuel cells an attractive and environmentally friendly option for power generation.