Xenon trapping longevity in diverse metal-supported silica nanocages

Noble gases are chemically inert elements used in lighting, anesthetics, and semiconductor industries, among others. Their management is important in nuclear reactors, and their detection is important in nuclear non-proliferation. They can also be dangerous, as radon causes lung cancer. Cryogenic distillation is typically used to obtain high-purity noble gases but is expensive and energy-intensive. A new technique physically traps xenon in silica nanocages produced from DodecaHydroxy Polyhedral Oligomeric Silsesquioxane on a ruthenium thin film. Here we present xenon trapping in silica nanocages on Ag(111), Au(111), and Ru(0001) single crystals, and analyze the results by x-ray photoelectron spectroscopy (XPS) in UHV. We deposited nanocages on single crystals with a Langmuir-Blodgett trough; subsequent calcination and reduction yielded a layer of nanocages on the metallic supports. Nanocages on all substrates still had xenon after 8 hours; greater longevity occurred on Ru(0001) and Au(111) compared to Ag(111). Xenon was continuously lost over time, suggesting that trapped xenon is unstable during XPS x-ray exposure. Our results propose an energy-efficient, less expensive, substrate-modifiable xenon collection method that works at room temperature.