Platinum Group Metals (PGMs): The Six Rarest Catalytic Metals

What Are Platinum Group Metals?

The platinum group metals (PGMs) are six chemically similar metallic elements that sit together in groups 8, 9, and 10 of the periodic table. They are divided into two subgroups based on their geological behavior: the lighter palladium group (ruthenium, rhodium, and palladium) and the heavier platinum group (osmium, iridium, and platinum). All six share a silvery-white appearance, exceptional resistance to corrosion, high melting points, and powerful catalytic activity.

PGMs are among the rarest elements found in the Earth's crust, with total annual global production of platinum and palladium combined reaching only around 200 tonnes per year. Their extreme scarcity, combined with properties that no other materials can replicate, has led the United States, European Union, and Canada to classify PGMs as critical raw materials.

Unlike rare earth elements, which are relatively abundant but difficult to separate, PGMs are genuinely scarce. Global reserves are estimated at approximately 70,000 tonnes, and the economics of extraction are shaped by the fact that PGMs are always mined as a basket rather than individually. The ratio of metals in any given ore body is fixed by geology, meaning producers cannot simply increase output of a single metal without also producing the others.

The Six PGMs

Platinum (Pt)

The most recognized of the group, platinum has an atomic number of 78 and a melting point of 1,768 degrees Celsius. It is the benchmark metal for diesel catalytic converters, where it excels at oxidizing carbon monoxide and hydrocarbons under oxygen-rich conditions. Beyond automotive use, platinum is critical in petroleum refining as a catalyst for producing high-octane gasoline. The emerging hydrogen economy is creating substantial new demand: platinum is the catalyst of choice in proton exchange membrane (PEM) fuel cells and electrolyzers, with projected consumption in these applications alone reaching 143 tonnes by 2050. Platinum also serves important roles in jewelry, glass manufacturing, anti-cancer drugs, and cardiac implants.

Palladium (Pd)

Palladium, with atomic number 46, is the lightest and lowest-melting PGM. It has become the dominant catalyst in gasoline engine catalytic converters, often used in combination with platinum. Over the past two decades, palladium has frequently commanded prices higher than platinum due to tightening supply from Russia and South Africa and rising demand from stricter vehicle emission standards worldwide. Palladium also finds use in electronics, dentistry, and as an alloying agent in white gold jewelry.

Rhodium (Rh)

Rhodium (atomic number 45) is the most expensive of the PGMs on a per-ounce basis, at times reaching prices exceeding 20 times that of gold. Its primary function is the selective catalytic reduction of nitrogen oxides (NOx) in three-way catalytic converters, a role that no other element can perform as effectively. Rhodium is also used in glass manufacturing for its high melting point and thermal stability, and in optical coatings and jewelry for its mirror-like reflective finish. Because rhodium is always produced as a byproduct of platinum and palladium mining, its supply cannot be scaled independently, making it exceptionally volatile in price.

Ruthenium (Ru)

Ruthenium (atomic number 44) is the hardest of the PGMs and a valuable alloying agent that enhances the durability of platinum and palladium. Its primary industrial application is in electronics: just 0.1 grams of ruthenium can coat a full square meter of hard disk platter, making it essential to data storage technology. Ruthenium dioxide serves as a coating on titanium anodes used in chlorine and caustic soda production. In medicine, ruthenium compounds are being developed as next-generation anti-cancer agents with lower toxicity profiles than platinum-based drugs.

Iridium (Ir)

Iridium (atomic number 77) is the rarest and most corrosion-resistant of all PGMs. With the highest density of any element after osmium and a melting point of 2,447 degrees Celsius, iridium performs in extreme environments where no other metal can survive. NASA uses iridium in spacecraft and deep-space communication systems. In the energy transition, iridium is a critical catalyst in PEM electrolyzers for green hydrogen production, with projected demand of 38 tonnes by 2050. Iridium-192 isotopes are widely used in industrial radiography to detect structural defects in pipelines and metal components. South Africa supplies over 93 percent of the world's iridium.

Osmium (Os)

Osmium (atomic number 76) is the densest naturally occurring element and the scarcest of all PGMs. Its extreme hardness makes it useful primarily as an alloying agent with other PGMs, particularly in applications requiring exceptional wear resistance such as fountain pen tips, electrical contacts, and surgical implants. Osmium also finds niche applications in fuel cells and forensic science. Very few companies worldwide have the capability to extract osmium into a saleable product, and it remains the least commercially significant member of the group.

Applications and Demand

The automotive industry is by far the largest consumer of PGMs. In 2024, catalytic converters accounted for 61 percent of combined fresh demand for platinum, palladium, and rhodium. Every gasoline and diesel vehicle sold with an internal combustion engine contains between 2 and 7 grams of PGMs in its exhaust system, depending on the engine type and emissions standard.

Beyond automotive catalysis, PGMs serve critical roles in:

• Hydrogen energy: Platinum and iridium are essential catalysts in fuel cells and electrolyzers that produce and consume green hydrogen
• Electronics: Ruthenium in hard drives, palladium in multilayer ceramic capacitors, and platinum in semiconductor manufacturing equipment
• Chemicals and petroleum: Platinum catalysts in oil refining and nitric acid production
• Medical devices: Platinum in anti-cancer chemotherapy (cisplatin and carboplatin), iridium in radiotherapy, and PGM alloys in implants
• Glass manufacturing: Platinum and rhodium crucibles and bushings for fiber glass and LCD glass production
• Jewelry: Platinum jewelry accounts for roughly 20 percent of total platinum consumption
• Aerospace and defense: Iridium and platinum in aerospace components, spark plugs, and sensor systems

Supply Chain and Geopolitics

PGM supply is among the most geographically concentrated of any mineral group. Over 70 percent of platinum comes from South Africa, whose Bushveld Igneous Complex is the largest known PGM deposit on Earth. Russia is the world's leading palladium producer, accounting for roughly 40 percent of global output. Together, these two countries control the vast majority of primary PGM supply, creating significant supply chain vulnerability.

South African PGM mining faces structural challenges. Ore grades decline with depth, and at depths of 1,800 meters below the surface, rock temperatures can reach 50 to 60 degrees Celsius, making extraction increasingly difficult and expensive. The industry also consumes enormous quantities of water, approximately 743 cubic meters per kilogram of metal extracted.

Geopolitical risk compounds supply uncertainty. Western sanctions on Russia following the invasion of Ukraine have disrupted palladium trade flows, while resource nationalism in South Africa periodically threatens production stability. In late 2025, China designated platinum as a strategic critical mineral, mirroring its approach to rare earths and signaling plans to build strategic stockpiles and develop domestic processing capacity. The launch of platinum and palladium futures on the Guangzhou Futures Exchange further formalized China's push for pricing influence.

These dynamics have intensified friendshoring efforts by Western nations. The United States, the fifth-largest global palladium producer, and Canada are exploring expanded domestic production, while Brazil has emerged as a potential new supply jurisdiction.

Recycling and Sustainability

PGM recycling is one of the most effective secondary supply sources for any metal group. Over 150 tonnes of PGMs are recovered annually, with roughly 75 percent coming from spent automotive catalytic converters. The economics are compelling: PGM concentrations in waste catalytic converters range from 2,000 to 5,000 grams per tonne, nearly 1,000 times higher than the 2 to 10 grams per tonne found in primary ore.

In 2022, platinum and palladium recovered from spent catalysts and e-waste totaled approximately 124 tonnes, representing 24 percent of total supply. As the global fleet of vehicles equipped with catalytic converters continues to age, the volume of end-of-life catalysts available for recycling is expected to grow steadily through 2040.

Technological innovation is also reducing PGM intensity. The platinum loading in fuel cells has fallen from 1.0 grams per kilowatt in the 1990s to 0.3 grams per kilowatt today, a trend that helps manage demand growth even as fuel cell deployment scales. Combined with advances in circular economy practices, recycling and thrifting will play central roles in ensuring long-term PGM availability.

Market Dynamics and Pricing

PGMs are traded on major commodity exchanges and priced primarily through spot and contract markets, with key price benchmarks set by the London Platinum and Palladium Market (LPPM) and Johnson Matthey. Price volatility is a defining feature of PGM markets, driven by the extreme concentration of supply, inelastic demand from emissions regulations, and the basket mining constraint that prevents producers from adjusting output of individual metals.

Rhodium exemplifies this volatility: its price surged from around $2,500 per ounce in early 2020 to over $29,000 per ounce in March 2021 before falling back dramatically. Platinum and palladium markets have seen significant price divergence over the past decade, with palladium overtaking platinum in price due to its dominant use in gasoline catalytic converters during a period of rising emissions standards.

Government and private sector stockpiling adds another layer of complexity. China's strategic classification of platinum has raised concerns about state-directed accumulation, while automotive manufacturers maintain offtake agreements with mining companies to secure long-term supply.