AQA GCSE Chemistry

Revision Notes

5.2.3 Electrode Reactions in Hydrogen Fuel Cells

Higher Tier Only

Electrode Reactions in Hydrogen Fuel Cells

  • The cell consists of an electrolyte which is usually phosphoric acid and porous carbon electrodes coated with a catalyst
  • Hydrogen enters at the anode where it is oxidised and oxygen enters at the cathode where it is reduced
  • The following reaction occurs at the cathode:

2H2 → 4H+ + 4e

  • At the anode the following reaction takes place:

4H+ + O2 + 4e → 2H2O

  • The overall reaction is:

2H2 + O2→ 2H2O

  • The electrons move around the external circuit from the cathode to the anode
  • This movement of electrons is used to drive an electric motor

Exam Tip

Remember two half equations combined will give you the full ionic equation.

Author: Francesca

Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.

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