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Title: An in-situ cell for characterization of solids by soft X-rayabsorption

Abstract

An in-situ cell using ''lab-on-a-chip'' technologies has been designed and tested for characterization of catalysts and environmental materials using soft X-ray absorption spectroscopy and spectromicroscopy at photon energies above 250 eV. The sample compartment is 1.0 mm in diameter with a gas path length of 0.8 mm to minimize X-ray absorption in the gas phase. The sample compartment can be heated to 533 K by an Al resistive heater and gas flows up to 5.0 cm{sup 3} min{sup -1} can be supplied to the sample compartment through microchannels. The performance of the cell was tested by acquiring Cu L{sub 3}-edge XANES data during the reduction and oxidation of a silica-supported Cu catalyst using the beam line 11.0.2 Scanning Transmission X-ray Microscope (STXM) at the Advanced Light Source of LBNL. Two-dimensional images of individual catalyst particles were recorded at photon energies between 926 eV and 937 eV, the energy range in which the Cu(II) and Cu(I) L{sub 3} absorption edges are observed. Oxidation state specific images of the catalyst clearly show the disappearance of Cu(II) species during the exposure of the oxidized sample to 4% CO in He while increasing the temperature from 308 K to 473 K. Reoxidation restores themore » intensity of the image associated with Cu(II). L-edge XANES spectra obtained from stacks of STXM images show that with increasing temperature the Cu(II) peak intensity decreases as the Cu(I) peak intensity increases.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE Director. Office of Science. Office of AdvancedScientific Computing Research. Office of Basic Energy Sciences. ChemicalSciences Geosciences and Biosciences Division; National Institutes ofHealth HG01399; British Petroleum. Methane ConversionCooperative
OSTI Identifier:
900699
Report Number(s):
LBNL-57017; LBNL-55334
Journal ID: ISSN 0034-6748; RSINAK; R&D Project: CB1102; BnR: KC0302030; TRN: US0702368
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 75; Journal Issue: 10; Related Information: Journal Publication Date: October 2004
Country of Publication:
United States
Language:
English
Subject:
37; 36; 47; ABSORPTION; ABSORPTION SPECTROSCOPY; ADVANCED LIGHT SOURCE; CATALYSTS; COMPARTMENTS; ENERGY RANGE; ENVIRONMENTAL MATERIALS; GAS FLOW; HEATERS; MICROSCOPES; OXIDATION; PERFORMANCE; PHOTONS; SPECTRA; VALENCE

Citation Formats

Drake, Ian J., Liu, Teris C.N., Gilles, Mary, Tyliszczak, Tolek, Kilcoyne, A.L. David, Shuh, David K., Mathies, Richard A., and Bell, Alexis T. An in-situ cell for characterization of solids by soft X-rayabsorption. United States: N. p., 2007. Web.
Drake, Ian J., Liu, Teris C.N., Gilles, Mary, Tyliszczak, Tolek, Kilcoyne, A.L. David, Shuh, David K., Mathies, Richard A., & Bell, Alexis T. An in-situ cell for characterization of solids by soft X-rayabsorption. United States.
Drake, Ian J., Liu, Teris C.N., Gilles, Mary, Tyliszczak, Tolek, Kilcoyne, A.L. David, Shuh, David K., Mathies, Richard A., and Bell, Alexis T. Thu . "An in-situ cell for characterization of solids by soft X-rayabsorption". United States. doi:. https://www.osti.gov/servlets/purl/900699.
@article{osti_900699,
title = {An in-situ cell for characterization of solids by soft X-rayabsorption},
author = {Drake, Ian J. and Liu, Teris C.N. and Gilles, Mary and Tyliszczak, Tolek and Kilcoyne, A.L. David and Shuh, David K. and Mathies, Richard A. and Bell, Alexis T.},
abstractNote = {An in-situ cell using ''lab-on-a-chip'' technologies has been designed and tested for characterization of catalysts and environmental materials using soft X-ray absorption spectroscopy and spectromicroscopy at photon energies above 250 eV. The sample compartment is 1.0 mm in diameter with a gas path length of 0.8 mm to minimize X-ray absorption in the gas phase. The sample compartment can be heated to 533 K by an Al resistive heater and gas flows up to 5.0 cm{sup 3} min{sup -1} can be supplied to the sample compartment through microchannels. The performance of the cell was tested by acquiring Cu L{sub 3}-edge XANES data during the reduction and oxidation of a silica-supported Cu catalyst using the beam line 11.0.2 Scanning Transmission X-ray Microscope (STXM) at the Advanced Light Source of LBNL. Two-dimensional images of individual catalyst particles were recorded at photon energies between 926 eV and 937 eV, the energy range in which the Cu(II) and Cu(I) L{sub 3} absorption edges are observed. Oxidation state specific images of the catalyst clearly show the disappearance of Cu(II) species during the exposure of the oxidized sample to 4% CO in He while increasing the temperature from 308 K to 473 K. Reoxidation restores the intensity of the image associated with Cu(II). L-edge XANES spectra obtained from stacks of STXM images show that with increasing temperature the Cu(II) peak intensity decreases as the Cu(I) peak intensity increases.},
doi = {},
journal = {Review of Scientific Instruments},
number = 10,
volume = 75,
place = {United States},
year = {Thu Jan 04 00:00:00 EST 2007},
month = {Thu Jan 04 00:00:00 EST 2007}
}
  • No abstract prepared.
  • We present a novel in situ reaction cell for heterogeneous catalysis monitored in situ by x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS). The reaction can be carried out at a total pressure up to 1 atm, a regime that has not been accessible to comparable in situ techniques and thus closes the pressure gap to many industrial standard conditions. Two alternate catalyst geometries were tested: (A) a thin film evaporated directly onto an x-ray transparent membrane with a flowing reaction gas mixture behind it or (B) a powder placed behind both the membrane and a gap ofmore » flowing reaction gas mixture. To illustrate the working principle and feasibility of our reaction cell setup we have chosen ethylene epoxidation over a silver catalyst as a test case. The evolution of incorporated oxygen species was monitored by total electron/fluorescence yield O K-XAS as well as O K-RIXS, which is a powerful method to separate contributions from inequivalent sites. We find that our method can reliably detect transient species that exist during catalytic reaction conditions that are hardly accessible using other spectroscopic methods.« less
  • An in situ flow electrochemical cell has been designed and fabricated to allow better seal under UHV chamber thus to achieve a good signal to noise ratio in fluorescence yield detection of X-ray absorption spectra for spectroelectrochemical study. The cell also stabilizes the thin silicon nitride membrane window in an effective manner so that the liquid cell remains intact during X-ray absorption experiments. With the improved design of the liquid cell, electrochemical experiments such as cyclic voltammetry have been performed for 10 cycles with a good stability of sample window. Also an operando electrochemical experiment during photoelectrochemistry has been performedmore » on n-type hematite electrode deposited on silicon nitride window. The experiment allows us to observe the formation of two extra electronic transitions before pre edge of O K-edge spectra.« less