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How Do Catalytic Converters Work in Cars?

Car’s have a huge number of different parts responsible for different mechanical processes, and they all work together to make your vehicle work as it should. As a result of all of that, however, a lot of other things happen outside of making your vehicle do what it needs to as well. One of the largest of those producing a byproduct is the combustion in your engine, and as a result, you may well be asking how do catalytic converters work to make all of the emissions that come from it safer to the world. It’s a whole area of science of its own. 

That is all because of the unique process behind how it works. In reality, it’s a complicated process of making a chemical reaction happen as fast as it possibly can (because that’s what a catalyst is), and making sure that it is done smoothly. All of that happens in one silent movement too, so there’s lots of fascinating information to understand. See what engine size is right fit for you.

Let’s take a look. 

Why We Need a Catalytic Converter 

Like we touched on above, this all boils down to one thing and one thing only. Combustion. The reaction that goes on inside of your engine to make your car burn fuel and move as a result. It isn’t all as smooth sailing as it should be, and that’s why we need a catalytic converter to do what it does. 

In a perfect world, it’s actually really simple. Perfect combustion means that a clean burn takes place, and as a result, there’s no remnant other than carbon dioxide and water. These are both relatively harmless. That’s all well and good. 

What isn’t so practical, however, is the fact that this is near enough impossible, especially in an environment like a car engine. Instead, the burn is inefficient for the most part, and carbon and hydrogen (or hydrocarbons) are released as a result. These, unlike their harmless counterparts, are really bad news. 

As a result of all of that, we have purpose built catalytic converters to help make the impossible, more possible; even if that isn’t a direct result. 

What a Catalytic Converter Does 

These unclean burns that we mentioned do a few different things that the catalytic converter needs to address how it works. To understand how and most importantly if catalytic converters do work, we need to address what these are and the exact way a catalyst helps to put them right in the long term and the short term. 

Reduction Catalysts 

Firstly, we have reduction catalysts which are in your converter. This deals with the issue of your available oxygen binding to the nitrogen in the air under heat by making them split up again into simply oxygen and nitrogen. These are massively apparent in the air around us already, so that therefore means that everything is okay to move forwards. 

Oxidation Catalyst 

Aside from this reaction, there’s another one that takes place as well in your converter to make sure everything is nice and efficient. This time, it makes things seven more efficient by using that oxygen created from the reduction reaction. By using this, we solve the original problem we had from the unclean burn, and use the oxygen to bind to the carbon monoxide (CO) that was produced (making carbon dioxide, CO2), as well as binding to the hydrogen to make water (H2O). 

How the Catalytic Converter Reacts 

Now that we have covered the essentials of what’s going on, the very last thing to look at is how this is all occurring at the same time and in a way that can keep happening over time. Again, it does actually come down to just a few simple components. Mainly, that comes from three metals that react with the gasses we’re looking at to cause the reaction. They are: 

  • Platinum (Both) 
  • Palladium (Oxidation) 
  • Rhodium (Reduction) 

All of these are just as important as each other, and although they all play there part with a lot of other materials, these are the foundations of what we’re looking at here. 

To make all of that happen in the most impressive way still, we also need to remember one more thing. That is to make sure the reaction is taking place in the best way possible, it also means that we have to maximise the surface area involved to allow the most reactions to take place at the same time. To do that, we have biomimicry to thank. 

By taking inspiration from nature, we can learn from some of the most advanced structures in the world to help make our systems and more importantly, our cars, be the best that they can. To really understand how a catalytic converter works, it’s wise to know what it looks like under your car, and it all comes down to a large and very long honeycomb type structure. This maximises the strength of the converter as well as the surface area for reactions, and that’s what’s inside your converter. 


All in all, that’s the whole process of how catalytic converters do actually work effectively. In summary, it all comes down to these few simple processes: 

  1. Combustion produces hydrocarbons due to a lack of oxygen in the engine 
  1. Reduction reactions make more oxygen form the oxygen and nitrogen that bond together during the burn 
  1. Oxidation reactions bind oxygen to the hydrocarbons creating carbon dioxide and water 
  1. Much cleaner emissions are released from your exhaust after passing through your catalytic converter 

Essentially, that is the whole system explained. It’s vital to ensure that your car is running as it should be without any issues and making sure your car is legal and roadworthy, which is only becoming more important as time goes on as well. 

In fact, they may actually have 2 converters in the same car with more recent developments, but the principles always remain the same. 

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