What is the Principle of Copper Oxide Purifying Automobile Exhaust?

Copper oxide primarily acts as a catalyst in automobile exhaust purification, converting harmful substances into harmless ones through a catalytic reaction. Copper oxide's catalytic activity reduces the activation energy of chemical reactions, accelerating the reaction rate and thus purifying automobile exhaust.
The main harmful components of automobile exhaust are carbon monoxide, nitrogen oxides, and hydrocarbons. Carbon monoxide is a toxic substance primarily produced by incomplete combustion. Copper oxide reacts with automobile exhaust at high temperatures, converting harmful substances into harmless ones. This works by providing active sites on the copper oxide surface, adsorbing CO and O₂ molecules, causing O₂ to decompose into reactive oxygen atoms, which then combine with CO to form CO₂.
Nitrogen oxides are a major cause of acid rain. Copper oxide catalyzes the reduction of NOₓ with CO (or HC) to produce nitrogen (N₂) and CO₂ (or H₂O). This works by adjusting the valence of nitrogen in the reaction (from +2 to 0) through electron transfer, while simultaneously promoting the oxidation of CO (from +2 to +4), achieving simultaneous NO reduction and CO oxidation.
Hydrocarbons are produced by incomplete combustion of fuel and contribute to air pollution. Copper oxide catalyzes the reaction between HC and O₂ to produce CO₂ and H₂O. The principle is that the copper oxide surface adsorbs HC molecules and O₂, accelerating the complete combustion of HC and preventing unburned HC from being released into the air.
Copper oxide is also more cost-effective than precious metal catalysts and can improve overall purification effectiveness, offering greater cost control advantages and making it more suitable for large-scale factories and enterprises.

Author: Hazel
Date: 2025-08-20