Researchers from Seoul National University’s College of Engineering developed a technology to quickly assess the durability of hydrogen fuel cell catalysts and identify the causes of degradation through joint research with Hyundai Motor Company.
The research team of professors Park Jeong-won and Ryu Jae-yoon from the Department of Chemical and Biological Engineering at Seoul National University revealed on the 7th that they developed a new technology called "electrochemical liquid cell transmission electron microscopy (e-LCTEM)" that can rapidly evaluate the durability of hydrogen fuel cell catalysts in cooperation with Hyundai Motor Company. The research findings were published in the Journal of the American Chemical Society (JACS) on Dec. 24 last year.
Hydrogen fuel cells are gaining attention as an eco-friendly energy technology that can replace fossil fuels. They generate electricity using hydrogen as fuel and emit only pure water as a byproduct, making them environmentally friendly. High energy density and fast charging speed are also strengths of hydrogen fuel cells.
However, the core material of the fuel cell catalyst, which promotes the electricity generation reaction, cannot avoid structural damage or gradual performance degradation during use. This degradation phenomenon is one of the biggest obstacles to the commercialization of hydrogen fuel cells. To operate hydrogen fuel cells stably, it is essential to accurately identify the causes of degradation, but directly observing structural changes of catalysts at the nanoscale (nano, 1 billionth of a meter) in the liquid electrolyte environment where the hydrogen fuel cells operate is technically very challenging.
The new electron microscopy technology developed by the research teams of Seoul National University and Hyundai Motor Company can complete the durability evaluation of hydrogen fuel cell vehicles in just a few hours. Previously, it required driving tens of thousands of kilometers for durability evaluation. This has dramatically reduced evaluation expenses and allowed for more efficient durability verification.
The research team validated the new technology using the representative catalyst of hydrogen fuel cells, "platinum nano-particle carbon support hybrid catalyst (Pt/C)." They tracked and observed the degradation process of the platinum-carbon catalyst over time in an environment where electricity flows while the cell operates. While the existing method compared before and after the operation of the fuel cell in a fragmented manner, the research team succeeded in observing structural changes in real-time.
As a result, it was discovered that in the voltage environment where both the dissolution of platinum nanoparticles and the corrosion of the carbon support are induced, smaller platinum nanoparticles exhibited high mobility. They tended to cluster with surrounding particles or detach from the support, while larger particles showed lower mobility and high structural stability. This marks the first revelation that the size of the catalyst particles significantly affects the degradation process.
Professor Park Jeong-won noted, “This research lays the foundation to quickly and accurately assess the durability of hydrogen fuel cell catalysts, and it is significant in shedding new light on the fundamental causes of catalyst performance degradation.” Professor Ryu Jae-yoon also commented, “With this research that accurately understands the causes of catalyst degradation and proposes improvement directions, I expect that a more stable and efficient high-performance hydrogen fuel cell system will be developed in the future.”
Reference materials
JACS (2024), DOI: https://doi.org/10.1021/jacs.4c08825