A catalyst in a fuel cell speeds up the chemical reactions necessary for generating electricity. The catalyst lowers the activation energy required for these reactions, making them happen more efficiently.
Catalyst Function in Fuel Cells
Fuel cells rely on catalysts to facilitate the oxidation of fuel (typically hydrogen) and the reduction of an oxidant (typically oxygen). These reactions occur at the anode and cathode, respectively.
- Anode (Oxidation): At the anode, the catalyst, often platinum, facilitates the splitting of hydrogen molecules into protons (H+) and electrons (e-). This process is critical for releasing electrons that create an electric current.
- Cathode (Reduction): At the cathode, another platinum catalyst (or a different material) enables oxygen reduction by reacting with the protons generated at the anode and electrons that have traveled through the external circuit, ultimately producing water (H2O). This reaction completes the circuit and generates the waste product of the fuel cell.
The following table summarizes the role of the catalyst on each side of the fuel cell:
| Location | Reactant(s) | Product(s) | Catalyst Role |
|---|---|---|---|
| Anode | Hydrogen (H2) | Protons (H+), Electrons (e-) | Splits hydrogen molecules into protons and electrons. |
| Cathode | Oxygen (O2), Protons (H+), Electrons (e-) | Water (H2O) | Enables oxygen reduction to form water. |
Without the catalyst, these reactions would occur too slowly to generate a useful amount of electricity.
