What chemical reactions happen in a Catalytic converters ?

Catalytic converters use reduction and oxidation ( reactions to reduce harmful emissions.

They use a reduction catalyst composed of platinum and rhodium. It helps reduce nitrogen oxides (NO_x) by removing nitrogen atoms from nitrogen oxide molecules (NO and NO₂). This lets the free oxygen form oxygen gas (O₂). Then, the nitrogen atoms attached to the catalyst react with each other. This reaction creates nitrogen gas (N₂).

Catalytic converter also use an oxidative catalyst composed of platinum or palladium. It helps reduce hydrocarbons (HC) and carbon monoxide (CO). To start with, carbon monoxide and oxygen combine to form carbon dioxide (CO2). Then, unburnt hydrocarbons and oxygen combine to form carbon dioxide and water.

Oxidation reactions for carbon monoxide and unburned hydrocarbons (© 2019 Let’s Talk Science).Modern catalytic converters also use oxygen sensors. They’re sometimes called . They control how much extra oxygen gets pumped into the exhaust stream.

Maintaining the correct amount of oxygen makes the reduction and oxidation reactions more efficient.Researchers are looking at whether gold could be used in catalytic converter. That might sound expensive.

But gold is actually cheaper than many other noble metals. And there’s more of it! In fact, we could run out of metals like platinum in the next couple of decades. In some places, people even steal catalytic converters just to get at the precious noble metals inside!