Chang Liu, Thomas Mallouk, and their colleagues at the University of Pennsylvania, University of Virginia, and Cornell University published recent work using their Hummingbird Scientific in-situ TEM liquid cell sample holder to investigate nanoscale Pt catalyst stability and performance in alkaline fuel cell environment. Commercial Pt-C was compared under in-situ and ex-situ scanning transmission electron microscopy (STEM) to a composite cathode with Nb-doped brookite TiO₂ nanorods to lend stability to the Pt-nanoparticle catalysts.

The liquid electrochemistry cell allowed for biasing of a three-electrode system on the microfabricated chip, at various voltages, with in situ imaging of structural changes. The composite cathode outperformed the commercial Pt-C in power density and voltage retention, effectively immobilizing the Pt-nanoparticles. A solvent residue derived from N-methylpyrrolidone (NMP) was found to play an important role in charge transfer and mass transport. The ionomer-free Nb-TiO₂ catalyst support as an alternative to carbon will improve anion exchange membrane alkaline fuel cell technology.

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Reference:

Chang Liu, Wonil Jung, Sungho Jeon, Grayson Johnson, Zixiao Shi, Langqiu Xiao, Shengsong Yang, Cheng-Yu Chen, Jun Xu, Cherie R. Kagan, Sen Zhang, David A. Muller, Eric A. Stach, Christopher B. Murray, and Thomas E. Mallouk. Cell Rep. Phys. Sci. 5 (7) 102090 (2024). DOI: 10.1016/j.xcrp.2024.102090