Cooler path to better fuel cells: Low-melting metals break the heat barrier for high-performance catalysts
image: Mechanism of M’-facilitated ordering process and fuel cell performance of various catalysts
Credit: Yan Wan, Mo Zhang & Yangming Lin.
The widespread adoption of proton exchange membrane fuel cells (PEMFCs) in heavy-duty vehicles has long been hindered by a "heat paradox." While structurally ordered L1₀-type platinum-based catalysts offer the best durability and activity, synthesizing them traditionally requires scorching temperatures above 600°C. This intense heat causes nanoparticles to clump together (sintering), which actually limits their performance.
Now, a new highlight published in the journal ENGINEERING Energy (formerly Frontiers in Energy) details a creative solution to this problem. Researchers from the Chinese Academy of Sciences discuss an innovative "low-melting-point metal" strategy that allows these high-performance catalysts to be produced at much milder temperatures.
By incorporating small amounts of metals with low melting points—such as Tin (Sn, 231.9°C), Indium (In, 156.6°C), or Gallium (Ga, 29.8°C)—scientists can effectively weaken the internal atomic bonds of the alloy. This lowers the energy barrier required for atoms to organize themselves into the desired ordered structure.
"This strategy successfully lowers the ordering temperature of PtM alloys to below 450°C," notes the research team highlighted in the report. This "cool" synthesis not only prevents the destructive sintering of particles but also enables the production of catalysts with a high platinum content (over 40 wt.%), which is critical for making fuel cell components thinner and more efficient.
The results are record-breaking. One specific catalyst, L1₀-Pt₅₀Ni₃₅Ga₁₅/C, achieved a peak power density of 1.1 W/cm², surpassing the high-performance targets set by the US Department of Energy (DOE) for 2025. Even more impressively, the catalyst maintained its power after grueling durability tests of up to 90,000 cycles, showing its immense potential for heavy-duty transportation.
Beyond performance, the method is highly practical. It reduces energy consumption by up to 81% and cuts production time by more than half compared to conventional methods. Because it is compatible with standard chemical manufacturing techniques, this approach could be scaled up to produce catalysts by the ten-gram scale, bringing high-efficiency, zero-emission fuel cells one step closer to mass production.
JOURNAL: ENGINEERING Energy (formerly Frontiers in Energy)
DOI: https://doi.org/10.1007/s11708-024-0957-1
Article Link: https://link.springer.com/article/10.1007/s11708-024-0957-1
Cite this article: WAN Y, ZHANG M, LIN Y. Low-melting point metals facilitate synthesis of Pt-based intermetallic nanocrystals. Frontiers in Energy, 2024, 18(6): 727–729.