Fuel cell

Setup

Cathode: gold mesh

Anode: lead (Pb)

Solution: KOH

Reactions

At cathode,
O2 + 4e + 2H2O
--> 4OH-

At anode,
Pb + 2OH-
--> PbO + H2O + 2e

Function

Current flow is proportional to oxygen partial pressure.

The device act as a cell and no battery is required (unlike Clark electrode)

Advantage

• Accurate
• Portable
• Low maintenance

Disadvantage

• Slow (30 second response time)
• Limited but guaranteed life span
• If standard fuel cell used in presence of N2O, it may react with lead to produce N2, which may alter the pressure inside the cell and damage the cell.

Others

Compare with Clark electrode