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In Situ X-Ray Absorption Spectroscopy With Variable Sample Temperature, Gas Pressure, and Composition

Category

Characterization Tools

Laboratory

SLAC National Accelerator Laboratory

Description

We have developed a capillary-based in situ/operando sample cell for X-ray absorption and X-ray Raman spectroscopies. The sample cell is interfaced with a residual gas analyzer for characterizing evolution of vapor phase reaction products (e.g., for dehydrogenation or decomposition reactions). In situ measurements are typically conducted to address local structural deformations as they relate to material processing, performance, and durability. The hard X-ray energies are suitable for examining structural changes to MOF metal centers, metal hydrides, complex hydrides, MXenes, and catalysts.

Range of X-ray energies: 5-38 keV (K absorption edges: V through Ba, L absorption edges: I through Bi)

Max sample temperature: 1500 K (1300 K sustained operation)
Minimum sample temperature: 110 K (measured by internal thermocouple)

Maximum gas pressure: 200 bar (expected 650 bar by summer 2023)
Minimum gas pressure: 10-7 mbar (10-4 mbar pressure resolution)

Figure

Closeup of in situ X-ray absorption spectroscopy equipment suspending copper sample in center. Bottom: Graph charging energy in eV and normalized absorption in arb.u. for the material CuCOF as received, activated, and with hydrogen, all exponentially increasing in absorption at 8980 eV and peaking around 9000 eV before stabilizing around .9 arb.u. at higher levels of eV.

Cu-decorated COF-300 before and after exposure to 5 Bar hydrogen.