Fuel cells and corrosion

Twelve Standard >> Fuel cells and corrosion

Fuel Cells and Corrosion

Fuel Cells

Fuel cells are electrochemical devices that convert the chemical energy of a fuel directly into electrical energy through redox reactions, without combustion. Fuel cells are recognized for their high efficiency and environmentally friendly energy production

Working Principle of Fuel Cells

In a typical hydrogen-oxygen fuel cell:

At the anode, hydrogen gas (H₂) undergoes oxidation, releasing protons and electrons.
The electrons flow through an external circuit, producing electrical energy in the form of current.
The protons move through an electrolyte membrane to the cathode.
At the cathode, oxygen gas (O₂) combines with the electrons and protons to form water.

Reactions in Hydrogen-Oxygen Fuel Cell

Anode: H₂ → 2H⁺ + 2e⁻

Cathode: O₂ + 4H⁺ + 4e⁻ → 2H₂O

Overall Reaction: 2H₂ + O₂ → 2H₂O

Advantages of Fuel Cells

High efficiency and eco-friendly.
Continuous power supply as long as fuel is available.
No harmful by-products except water.

Corrosion

Corrosion refers to the slow deterioration of metals resulting from chemical interactions with environmental factors, typically involving moisture and oxygen. It affects the structural integrity and longevity of metal components.

Types of Corrosion

Dry Corrosion: Occurs in the absence of moisture, often due to chemical reactions with gases like oxygen or sulfur dioxide.
Wet Corrosion: Takes place in the presence of an electrolyte and involves electrochemical reactions, typically rusting of iron.

Electrochemical Theory of Corrosion

This theory explains corrosion as a redox process involving two half-reactions:

Anodic Reaction (oxidation): Metal atoms lose electrons and become metal ions.
Cathodic Reaction (reduction): Electrons are consumed by species like O₂ or H⁺.

Example: Rusting of Iron

Anode: Fe → Fe²⁺ + 2e⁻