What are the Key Challenges in Reducing Platinum Use in Catalysts?

Platinum is the gold standard in catalysis—quite literally, in terms of cost and prestige. For decades, it has been the workhorse of the chemical and automotive industries, particularly in hydrogen fuel cells and catalytic converters. Its ability to accelerate chemical reactions without being consumed makes it invaluable. However, platinum has a problem: it is rare, expensive, and subject to volatile supply chains.

For the green hydrogen economy to truly scale, the industry faces a critical hurdle: we need to reduce our reliance on this precious metal without sacrificing the performance that modern applications demand. This is the central challenge driving innovation at Momentum Materials.

The Platinum Paradox: Why Reduction is Necessary

Platinum is exceptionally active, making it ideal for the harsh environments inside fuel cells and electrolyzers. It facilitates the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) more efficiently than almost any other material.

However, the scarcity of platinum poses a significant barrier to mass adoption. If we were to replace every internal combustion engine vehicle with a hydrogen fuel cell vehicle today, using current platinum loadings, current annual production capacity can’t cover it. Platinum is also a major cost driver within the hydrogen fuel cell stack. To make clean energy technologies like proton exchange membrane fuel cells (PEMFCs) commercially viable, we must drastically reduce or eliminate platinum use.

The Durability Dilemma

The primary challenge in reducing platinum is maintaining durability. When engineers reduce the amount of platinum—often by using thin layers or nanoparticles dispersed on a support—the catalyst becomes more vulnerable.

In fuel cells, catalysts operate under high fluctuating voltages and acidic conditions. Thinner platinum layers can degrade rapidly through mechanisms like dissolution and Ostwald ripening (where smaller particles dissolve and redeposit onto larger ones, reducing overall surface area). As the active surface area shrinks, performance plummets.

Furthermore, “poisoning” remains a significant issue. Platinum is highly susceptible to contaminants like carbon monoxide or sulfur, which can block active sites and render the catalyst useless. High-loading platinum catalysts have enough active sites to tolerate some poisoning, but as we reduce the loading, the tolerance for impurities drops significantly. A low-platinum system simply has no margin for error.

Activity Loss in Low-Loading Systems

Reducing platinum isn’t just about using less material; it often involves alloying platinum with other metals (like cobalt or nickel) to boost specific activity. While these platinum alloys can initially outperform pure platinum, they introduce new stability problems. The non-precious metal component tends to leach out over time, leaving behind a platinum skeleton that may eventually collapse, leading to a loss of activity.

Achieving the same reaction rates with significantly less precious metal requires pushing the remaining platinum to work harder. This often leads to higher local current densities, which can accelerate degradation. It is a delicate balancing act: how do we get more power out of less metal without burning it out?

Exploring Alternatives: The Path to Platinum-Free

The ultimate goal for many researchers is the development of platinum-free catalysts. This involves shifting entirely to Earth-abundant materials.

• Platinum Alloys: As mentioned, alloying helps reduce platinum content but struggles with leaching.
• Non-Precious Group Metals: Materials based on iron, cobalt, or manganese are showing promise. However, their activity in acidic environments (typical of PEM fuel cells) is generally lower than platinum, and their stability remains a major hurdle.
• Advanced Carbon Supports: The material that holds the catalyst is just as important as the metal itself. Momentum Materials is investigating advanced nanoporous carbon structures that can stabilize smaller metal particles, preventing them from agglomerating or detaching.

While totally platinum-free catalysts are the “holy grail,” they are not yet ready for widespread commercial deployment in high-performance applications. The immediate, pragmatic step is ultra-low platinum loading—optimizing the structure at the nano-level to ensure every single atom contributes to the reaction.

The Balance: Cost, Performance, and Lifespan

The drive to reduce platinum is ultimately an economic equation. A cheaper catalyst that fails after 5,000 hours of operation is more expensive in the long run than a pricey one that lasts 20,000 hours.

For Momentum Materials, the solution lies in engineering. By manipulating the catalyst structure and its support system, we aim to protect the active sites, preventing degradation while minimizing the required mass of precious metals. The future of clean energy depends on solving this puzzle—doing more with less, without compromise. Contact us today to learn more about our cutting-edge research and development in sustainable energy solutions.