Hydrogen fuel cells are a promising clean energy option as they efficiently generate power by converting hydrogen and oxygen into electricity, with zero emission of carbon dioxide, particulate matter, and other air pollutants that may cause smog and other health problems. Hydrogen fuel cells have yet to be widely commercialized, despite their environmental benefits and years of development. That is because its power generation depends heavily on an electrocatalyst — which is largely comprised of the very expensive and rare metal platinum.
Researchers have strived to develop alternatives by replacing platinum with more common and inexpensive materials like iron-nitrogen-carbon. However, those materials have either proven inefficient in power generation or have suffered from poor durability.
Now, a research team led by Prof. Minhua Shao from the Department of Chemical and Biological Engineering at HKUST, discovered a new formula. It not only cuts down the proportion of platinum used by 80 percent, but it also set a record in terms of the cell’s durability level.
Despite a low portion of platinum, the new hybrid catalyst developed by the research team managed to maintain the platinum catalytic activity at 97% after 100,000 cycles of accelerated stress test, compared to the current catalyst which normally sees a drop of over 50% in performance after just 30,000 cycles. In another test, the new fuel cell did not show any performance decay after operating for 200 hours.
One reason behind such outstanding performance was the fact that the new catalyst has three different active sites for the reaction, instead of just one in current catalysts. Using a formula containing atomically dispersed platinum, iron single atoms, and platinum-iron nanoparticles, the new mix accelerates the reaction rate and achieves a catalytic activity 3.7 times higher than the platinum itself. Theoretically, the higher the catalytic activity, the greater the power it delivers.
Prof. Shao, also the Director of HKUST Energy Institute, said, “Hydrogen fuel cell is an energy conversion device essential for our aspiration of achieving a carbon neutral world, there is a need to expand its use amidst our fight against climate change. We are delighted to see our research findings bringing this goal a step closer. Thanks to the Government’s Green Tech Fund, we will seek to further refine the catalyst and make it compatible with fuel cell vehicles and other electrochemical devices.”
The study was financially supported by the National Key R&D Program of China, Shenzhen Science and Technology Innovation Committee, and the Research Grant Council of the Hong Kong Special Administrative Region. The research findings were recently published in the journal Nature Catalysis.
- According to the test protocols of US Department of Energy in assessing the durability of fuel cell.
- One cycle is equivalent to 3 seconds with voltage level at 0.6V, followed by another 3 seconds with voltage level at 0.9V.
- The voltage level is set at 0.6V.
Reference: “Atomically dispersed Pt and Fe sites and Pt–Fe nanoparticles for durable proton exchange membrane fuel cells” by Fei Xiao, Qi Wang, Gui-Liang Xu, Xueping Qin, Inhui Hwang, Cheng-Jun Sun, Min Liu, Wei Hua, Hsi-wen Wu, Shangqian Zhu, Jin-Cheng Li, Jian-Gan Wang, Yuanmin Zhu, Duojie Wu, Zidong Wei, Meng Gu, Khalil Amine and Minhua Shao, 2 June 2022, Nature Catalysis.
Funding: National Key Research and Development Program of China, Shenzhen Science and Technology Innovation Committee, the Research Grant Council of the Hong Kong Special Administrative Region, Innovation and Technology Commission of the Hong Kong Special Administrative Region, Foshan-HKUST Project, Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Shenzhen Natural Science Fund