What’s Inside a Catalytic Converter?

Catalytic converters have been fitted on vehicles from the factory since 1975. Catalytic converters greatly reduce the number of toxic emissions that come from operating an internal combustion engine. Today, without a cat, you will be unable to pass emissions tests that many states require regular tests. Naperville, Wheaton, or any other town within the Dupage county limits require emission testing, so you better have one!

Most car owners know the importance of catalytic converters in reducing the harmful gasses emitted during engine operation, but what’s actually inside them remains a mystery. In this article, we are going to go over what’s inside a catalytic converter, and why they work.

What is a catalytic converter?

A pair of catalytic converters in an exhaust system

The catalytic converter is an emissions control device located in the vehicle’s exhaust system. Cats are positioned closely after the exhaust manifold or headers, before the resonator or muffler. They accelerate a chemical reaction that changes toxic exhaust gases into less harmful emissions.

Catalytic converters contain a mix of ceramic and precious metals

A“catalyst” made up of various precious metals coats the ceramic material in a catalytic converter. The catalyst is responsible for the chemical reaction that converts harmful vapors like nitrogen oxide, carbon dioxide, and hydrocarbons into carbon monoxide and water vapor.

What does the inside look like?

The catalyst inside a catalytic converter

If you were to open up the metal canister of a catalytic converter, you would find a highly compact ceramic honeycomb structure. The honeycomb layout maximizes the catalyst surface area. Some catalytic converters use a less compact structure to benefit performance and exhaust flow. Emissions control is the primary focus of factory installed cats.


What metals are in a catalytic converter?

Catalytic converters use platinum, palladium, and rhodium to accelerate the chemical reaction needed to reduce NOx emissions. These metals coat the ceramic honeycomb core and react with the exhaust gasses that pass through on their way to the tailpipe.

These precious metals are what drive the prices of catalytic converters so high. This is why catalytic converters are such a common target for thieves. Used catalytic converters can bring $150 or more at a scrap yard. The owner, on the other hand, has to shell out hundreds (or thousands!) of dollars to replace it on their car.

Bring your car to Becker Service Center!

If you need to replace your catalytic converter or have any other exhaust service performed, the skilled technicians at Becker Service Center can help. Give us a call or schedule an appointment at our conveniently located Naperville repair shop today. We look forward to seeing you!