Near Ambient Pressure X-Ray Photoelectron Spectroscopy
Complete understanding of hydrogenation and dehydrogenation requires knowledge of the dynamic composition and chemical state of the surface while the reactions are taking place. Surface/gas reactions are believed to be a rate-limiting factor for many H storage materials and are controlled by the chemical and physical state of the surface and near-surface regions. Traditional XPS can only be used in ultra-high vacuum conditions, allowing only ex-situ hydrogenation experiments and subsequent XPS measurements in vacuum. But the chemical reactivity and surface species can vary greatly with and without gas pressure. Near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) provides this information. In situ studies with NAP-XPS can reveal the complex coupling between transport, surface reaction rates, and oxidation state changes when hydrogen storage materials (hydrides, sorbents) operate.1–9
Pressure range: UHV to 25 mbar
Sample temperature: Liquid N2 to >1,000°C
Energy resolution: <2.5 meV
Kinetic energy range: 5–3,500 eV
Detector: fast delay-line detector with 190 ps time resolution
Online and available for use in collaboration with HyMARC.
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