Platinum Catalysts: A Practical Selection Guide for Engineers

Platinum is one of the most important materials in modern catalysis. It accelerates numerous reactions that would take far too long independently. Whether it is purifying car exhaust or assisting in producing hydrogen gas, platinum plays a crucial role in a range of processes.

Figure 1. Platinum on Carbon Catalyst

Why Platinum Is Valued

Platinum derives its strength from a unique electronic configuration. It bonds with simple molecules such as hydrogen, oxygen, and carbon monoxide at an optimal intensity. The bond is strong enough to break existing bonds, yet not so strong that new products remain attached. In summary, platinum facilitates reactions efficiently.

Some of its most prominent properties are:

• High activity: It accelerates significant reactions such as oxygen reduction and hydrogen oxidation.
• Stability: Platinum can withstand harsh conditions without oxidising or corroding easily.
• Versatility: It serves multiple roles across the automotive, energy, and chemical sectors.

The drawback is that platinum is expensive. As of 05/03/2026, the spot price was approximately £1,645–£1,770 per troy ounce (APMEX). Prices have experienced high volatility recently due to geopolitical tensions, trading within a range of roughly £1,484 to £1,772 over the prior month. A significant portion of the supply originates from South Africa, which adds to the challenge of its availability.

Main Forms of Platinum Catalysts

There are several methods used to employ platinum in catalysis. We shall examine the most common.

Supported Nanoparticles

The most prevalent format is supported nanoparticles. Here, tiny particles of platinum (typically about 2 to 5 nanometres) are situated on a kind of support such as carbon or an oxide. This deliberate distribution ensures that all the platinum can effectively expedite reactions. This form is commonly found in:

• Electrodes in fuel cells
• Liquid-phase hydrogenation configurations
• Sensors that measure various chemical compounds

By employing small particles on a high-surface-area support, the expensive metal can be used more efficiently.

Coated Substrates

Another common method involves coating a solid material, such as ceramic or metal honeycombs, with a thin layer of platinum. These coatings are primarily used in contexts requiring a large catalyst surface area.

For example, consider systems located within a car's exhaust line. The platinum layer aids in converting harmful gases such as carbon monoxide, hydrocarbons, and nitrogen oxides into less harmful substances. This method is reliable, albeit it utilises more metal per device.

Advanced Structures

Novel designs include core-shell materials and catalysts containing single platinum atoms. In a core-shell structure, a less expensive material forms the inner core, while a very thin layer (merely two or three atoms thick) of platinum constitutes the outer shell. This design effectively extends the utilization of costly platinum.

Figure 2. Core-shell structure 

Single-atom catalysts comprise individual platinum atoms dispersed on a support. These offer theoretical maximum efficiency; however, maintaining the position of the atoms can be challenging.

Ultra-low platinum loading designs are also under exploration. Even with less than 2% platinum, these catalysts can sometimes match the performance of traditional counterparts.

Key Applications of Platinum Catalysts

Platinum finds application across various sectors critical to industry and everyday life.

Automotive Emission Control

In vehicles, platinum plays a critical role in reducing harmful exhaust emissions. The catalyst facilitates the conversion of carbon monoxide, unburned hydrocarbons, and nitrogen oxides into carbon dioxide, water, and nitrogen. A small amount—between 1 and 3 grams per vehicle—is generally sufficient.

With structures built on a washcoated honeycomb, these catalysts work diligently to mitigate polluting emissions. Under standard operation, they can eliminate over 90% of pollutants. Many vehicles can exceed 150,000 kilometres without a significant decline in performance.

Fuel Cells

Fuel cells convert hydrogen and oxygen into electricity, with water as the only by-product. In these systems, platinum nanoparticles are typically dispersed on a carbon support, frequently measuring around 2 to 3 nanometres in size to optimise performance. A modern fuel cell may use between 0.1 and 0.4 milligrams of platinum per square centimetre, and advancements aim to further reduce this amount. No other metal matches platinum in accelerating the oxygen reduction reaction in an acidic environment.

Chemical Synthesis

Platinum catalysts also play a role in chemical manufacturing. In processes such as nitric acid production, platinum gauze, along with a small amount of rhodium, catalyses the oxidation of ammonia at high temperatures (around 850 to 900°C). In the refining of petroleum, platinum is employed to enhance the quality of gasoline by transforming lower-quality inputs into higher-octane products. Furthermore, platinum catalysts help achieve high selectivity in hydrogenation reactions used in producing fine chemicals.

Emerging Role in the Hydrogen Economy

The transition towards a hydrogen-based energy system is examining new applications for platinum. In water electrolysis, which separates water into hydrogen and oxygen, platinum plays a role at the cathode.

Certain new designs employ armour-like catalysts wherein a cobalt-nickel alloy resides within a graphene shell with a few surface platinum atoms. Other studies utilise catalysts featuring single platinum atoms, which generate many hydrogen molecules per atom. Furthermore, zinc-air batteries are exhibiting potential with ultra-low platinum compositions, achieving higher power output and solid stability over extensive usage periods.

How to Choose the Right Platinum Catalyst

When selecting a platinum catalyst, several critical points should be considered:

1. Activity: Determine the required speed of the reaction. Generally, smaller particles or specific alloys yield a high activity level.
2. Selectivity: It may be necessary for the catalyst to favour one reaction over others. This sometimes necessitates choosing a specific particle size or support.
3. Durability: Assess the lifespan of your catalyst. Larger particles or stronger supports can enhance longevity.
4. Operating Conditions: Evaluate the working temperature, pressure, and other environmental factors. A catalyst that performs well at lower temperatures may fail in higher temperature settings.
5. Cost: Acknowledge that platinum is expensive. The initial cost should be balanced against potential long-term savings if the catalyst demonstrates longer durability.

A quick selection guide might involve listing the application, the recommended form, and factors such as thermal stability or resistance to poisoning.

The Bottom Line

Platinum catalysis encompasses a range of applications and tools designed to address diverse challenges.

For most requirements, supported platinum nanoparticles on carbon or oxide have consistently performed well. If you are undertaking a high-volume, cost-sensitive project, you may consider ultra-low loading forms. For the most demanding conditions—such as high temperature, the risk of poisoning, or extensive service life—you may opt for specialised forms like coated substrates or stable alloys.

When in doubt, keep the approach simple. Test your selections under realistic conditions, adjust as necessary, and allow empirical experience to inform your choices. Reliable engineering often relies on practical measures and a readiness to iterate.

For quality materials that you can trust in these applications, consider the offerings from Stanford Advanced Materials (SAM).

Sources & Further Reading

• Brookhaven National Laboratory. "Scientists Develop Fuel-Cell Catalyst for Heavy-Duty Vehicles." 2025.
• Xu, M. et al. "Enriched asymmetric π electrons confining single-site Pt for acidic hydrogen evolution." Joule, 2025.
• Hofer, J. et al. "Platinum-catalysed conversion of sulphur species." CRU Group, Sulphur 421, 2025.
• Gasteiger, H.A. et al. "Activity benchmarks for oxygen reduction catalysts." Applied Catalysis B, 2005.
• Nanjing Tech University. "Ultra-low Pt catalyst for zinc-air batteries." Frontiers in Energy, 2025.
• U.S. Department of Energy. Hydrogen and Fuel Cells Program Annual Progress Report, 2023.
• Johnson Matthey, Tanaka, Umicore product literature.
• Emitec, P&P Industries technical documentation.

Data on platinum prices and market trends from Platinum Guild International, E4tech and APMEX.