The Role of Iridium in Catalytic Converters Explained

Catalytic converters have long been the backbone of modern emissions control. Installed within a vehicle’s exhaust system, they transform harmful exhaust gases into less toxic substances before they leave the tailpipe.

At the heart of this process are precious metals: platinum group metals (PGMs) such as platinum, palladium, and rhodium, which drive the chemical reactions that reduce these harmful vehicle emissions.

In recent years, recyclers and professionals in the automotive industry have begun hearing more about another PGM: iridium. While not traditionally associated with most automotivecatalytic converters, iridium is increasingly discussed in technical circles due to its unique material properties and potential performance advantages under extreme conditions.

So what role does iridium actually play? Is it present in catalytic converters? And what could it mean for refiners, buyers, and recyclers working with precious metals? Let’s break it down.

What is iridium?

Iridium is one of the platinum group metals found on the periodic table, alongside platinum, palladium, rhodium, ruthenium, and osmium. Like the other PGMs, it’s classified as a rare metal, and it’s exceptionally scarce in the earth's crust. In fact, iridium is rarer than gold and less abundant than platinum or palladium.

Geologically, iridium is often recovered as a byproduct of platinum and nickel mining, particularly in regions like South Africa, one of the world’s leading sources of platinum group metals.

What makes iridium stand out among PGMs is its extraordinary physical and chemical characteristics:

• Exceptional corrosion resistance
• A remarkably high melting point (over 4,352°F)
• Outstanding stability at high temperatures
• Resistance to chemical attack, even in aggressive environments

These traits allow iridium to maintain structural integrity where many other metals would degrade. Its resistance to oxidation and chemical breakdown makes it particularly valuable in demanding industrial applications where high purity and durability are essential.

What is iridium used for?

Iridium isn’t as commonly discussed as platinum, palladium, or rhodium in the context of automotivecatalytic converters. You may have heard about it because it plays an important role in several high-performance industrial applications, like many of its PGM brothers and sisters do.

One well-known use of iridium is in spark plugs. Iridium-tipped spark plugs are installed in combustion engines for their durability and long service life. Thanks to iridium’s high melting point and resistance to wear, these spark plugs maintain consistent performance under high temperatures and pressure inside modern engines.

But that’s not all for iridium. It’s also used in:

• Electronics and specialized electrical contacts
• Medical devices requiring biocompatible, corrosion-resistant materials
• Aerospace components exposed to extreme heat and chemical stress
• Chemical processing equipment
• And so much more!

In chemical processing and catalytic environments, iridium is often used in oxide form or as part of advanced alloys. Its ability to facilitate chemical reactions without degrading makes it attractive in environments where stability and high-performance operation are required, like vehicles.

Emerging technologies, including fuel cells and advanced energy systems, have also explored iridium-based catalysts due to their ability to withstand aggressive operating conditions. We’ll discuss more below!

High melting point, corrosion resistance, and stability at high temperatures are precisely what make iridium a candidate for certain emissions-control applications.

Is iridium in catalytic converters?

The short answer is yes, but not in most traditional automotivecatalytic converters and not in amounts significant enough to merit processing.

Conventional catalytic converters primarily rely on three PGMs:

• Platinum, which supports oxidation reactions
• Palladium, which also promotes oxidation of hydrocarbons and carbon monoxide
• Rhodium, which is particularly effective at reducing nitrogen oxides (NOx)

Together, these precious metals convert harmful exhaust gases like nitrogen oxides, carbon monoxide, and hydrocarbons into nitrogen, carbon dioxide, and water vapor.

Iridium is not typically a primary metal in standard automotivecatalytic converters.

But it has been tested and used in certain advanced catalyst formulations. In specialized or experimental catalyst systems, iridium may be introduced to improve durability or enhance performance in extreme-duty or high-temperature environments.

Where iridium can be seen

As emissions standards tighten globally, catalytic converters must operate effectively under increasingly demanding conditions. Modern combustion engines can generate intense thermal stress within the exhaust system, particularly during aggressive driving cycles or temperamental events. Under these high temperatures, catalyst degradation becomes a serious engineering challenge.

Iridium’s stability makes it attractive in:

• Advanced high-performance catalyst coatings
• Specialty automotive applications
• Systems designed to withstand prolonged thermal cycling
• Certain industrial emissions-control systems

It’s important to note that there are two variables at play when it comes to iridium in catalytic converters from internal combustion engines. First, original equipment manufacturers (OEMs) don’t typically disclose exact metal compositions. And second, iridium is present in such low and insignificant amounts in specialty applications only.

Because of this, iridium recovery in traditional automotivecatalytic converters falls to zero.

The future of iridium in emissions technology

The automotive industry is navigating a complex transition. On one hand, electrification is accelerating. On the other, combustion engines remain dominant in many global markets. Even hybrid vehicles rely heavily on catalytic converters to control vehicle emissions during operation.

As global regulations targeting nitrogen oxides (NOx), hydrocarbons, and carbon monoxide become more stringent, catalyst systems must deliver higher conversion efficiency while surviving extreme conditions.

This is where iridium’s potential may become relevant.

Ultra-durable catalysts that maintain activity under high temperatures and resist chemical degradation are critical for next-generation emissions systems. While rhodium remains the key metal for NOx reduction, and palladium and platinum continue to dominate oxidation reactions, iridium may serve as a performance-enhancing component in future catalyst designs.

Additionally, research into advanced PGMs combinations like ruthenium, osmium, and iridium continues as manufacturers look for ways to balance performance, cost, and long-term durability.

Beyond the automotive industry, industrial applications such as chemical processing and stationary emissions control systems may further expand iridium’s use in catalyst technology.

For recyclers, this evolution means one thing: catalytic converter compositions are becoming more complex. As rare metals are incorporated into smaller quantities and more sophisticated coatings, high-quality refining processes become even more important.

Understanding what metals are present in your converters helps buyers and sellers make more informed decisions about pricing, recovery, and compliance.

Talk to our experts about catalytic converter metals.