Unlocking the Potential of Platinum-Free Catalysts in Hydrogen Fuel Cells

Hydrogen fuel cells are at the forefront of clean energy solutions, and platinum plays a central role in their functionality. As a catalyst in proton-exchange membrane fuel cells (PEMFCs), platinum's unique properties enable efficient energy conversion and durability. 

Hydrogen fuel cell. Image used courtesy of Adobe Stock

 

However, using this precious metal also presents significant challenges, including high costs, potential degradation, and environmental concerns. Recently, researchers from UNSW Sydney have embarked on a groundbreaking journey to understand and overcome these challenges. 

 

Platinum in Hydrogen Fuel Cells

Platinum is a key ingredient that plays a vital role in hydrogen fuel cells.

One place where platinum is particularly important is in PEMFCs. As a catalyst in the electrochemical reactions within a fuel cell, platinum facilitates the splitting of hydrogen gas into protons and electrons at the anode. At the cathode, it catalyzes the reaction of oxygen with protons and electrons to form water. The electrons generated in these reactions are harnessed to produce electricity.

 

Platinum is used as a catalyst in PEMs. Image used courtesy of Green Car Congress

 

The unique properties of platinum, such as excellent conductivity and chemical stability, make it highly efficient as a catalyst. This efficiency is essential for achieving high energy conversion rates in fuel cells, allowing them to compete with traditional energy sources. Platinum's stability under harsh conditions within a fuel cell also contributes to its durability. This leads to longer-lasting fuel cells, a significant advantage in commercial applications where longevity and reliability are key factors.

 

Challenges with Platinum

While platinum is instrumental in fuel cells, its utilization still presents several challenges.

One of the most significant challenges is the cost of platinum. As a scarce metal, platinum is difficult and expensive to mine. This high cost translates into a more expensive end product, limiting the commercial viability of fuel cells, especially in applications like automotive transportation, where cost competitiveness is crucial.

Durability is another concern. While platinum is known for its stability and resistance to corrosion, the conditions within a fuel cell can lead to degradation over time. This degradation can reduce the efficiency of the fuel cell, leading to decreased performance and a shorter lifespan. Understanding and mitigating this degradation is essential for the long-term success of hydrogen fuel cell technology.

Environmental considerations also influence the challenges facing platinum in hydrogen fuel cells. The mining and refining of platinum can have significant environmental impacts, including habitat destruction and pollution. These factors become increasingly important as the world moves towards more sustainable and environmentally friendly energy solutions. The use of platinum in fuel cells must align with broader environmental goals, adding another layer of complexity to its utilization.

 

UNSW Research

Recently, a group of researchers from UNSW Sydney aimed to address the many issues facing using platinum in hydrogen fuel cells.

Specifically, the team developed a method to understand why some catalyst materials are less stable than platinum, particularly in platinum-free fuel cells. They utilized three novel methods tested in the lab to quickly determine the stability of their platinum-free fuel cell and to understand the underlying reasons for any instability.

 

The research team from UNSW Sydney. Image used courtesy of UNSW Sydney 

 

Through these techniques, they discovered that up to 75% of the iron-based active sites in the fuel cell became inactive in the first 10 hours of operation, largely due to the loss of iron active sites, followed by carbon corrosion as the main degradation mechanism. Their approach allowed them to pinpoint what was happening and when – providing insights into the degradation process.

The significance of their work lies in the potential to develop materials with more stable active sites, leading to slower decay and improved stability of platinum-free catalysts. They believe other scientists can easily adopt their approach and will contribute to developing new materials targeting stability issues, thereby enhancing the future prospects of platinum-free catalysts in hydrogen fuel cells.