Hydrogen-Oxygen Fuel Cell | Chemistry for Grade 11 (IGCSE) PDF Download

Hydrogen Fuel Cells

• A fuel is a substance that releases energy when burned.
• Hydrogen serves as a fuel in rocket engines and fuel cells for powering certain vehicles.
• A fuel cell is an electrochemical cell where a fuel provides electrons at one electrode and oxygen receives electrons at the other electrode. 
  • Hydrogen: H₂ → 2H⁺ + 2e^–
  • Oxygen: O₂ + 4e^– → 2O^2–
• The hydrogen-oxygen fuel cell generates electricity by combining both elements, producing energy and water.
• The comprehensive equation for the reaction in a hydrogen fuel cell is:
  hydrogen + oxygen → water
• The hydrogen fuel cell configuration involves the intake of hydrogen and oxygen.
• Oxygen is provided by the incoming air while hydrogen serves as the fuel.
• The sole byproduct generated in this process is water.

Advantages & Disadvantages of Hydrogen Fuel Cells

Increasing Usage in Automotive Industry

• Hydrogen-oxygen fuel cells are progressively being employed in vehicles to supplant traditional petrol or diesel engines.

Advantages

• They generate no pollution, with water being the sole byproduct, unlike petrol engines that emit carbon dioxide and nitrogen oxides.
• They yield higher energy output per kilogram compared to both petrol and diesel.
• They incur no power loss during transmission since they lack moving components, unlike internal combustion engines.
• They operate quietly, resulting in reduced noise pollution when compared to petrol engines.

Disadvantages

• The materials required for manufacturing fuel cells are costly.
• Storing hydrogen is more challenging and expensive than storing petrol due to its high flammability, which can lead to explosions under pressure.
• Fuel cells experience reduced efficiency in low temperatures.
• There is a limited availability of hydrogen filling stations nationwide.
• Hydrogen is often obtained through processes involving the combustion of fossil fuels, resulting in the release of carbon dioxide and other pollutants into the atmosphere.