| Answer |
The oxygen partial pressure of gases including hydrogen and water vapor, is determined by the degree of the chemical reactions among oxygen, hydrogen and water vapor. At low temperatures, hydrogen or water vapor does not affect oxygen partial pressure, but at high temperatures where relating chemical reactions occur fast, water vapor is formed by the reaction between hydrogen and oxygen or decomposed into hydrogen and oxygen, which causes oxygen partial pressure to change. In most cases, operating temperatures of zirconia oxygen sensors are high enough for chemical reactions to occur. The increase or decrease in oxygen partial pressure is thermodynamically determined by the temperature and partial pressure of each gas. |
