A lab-based ambient pressure x-ray photoelectron spectrometer with exchangeable analysis chambers

Abstract

Ambient pressure X-ray photoelectron spectroscopy (APXPS) is a powerful spectroscopy tool that is inherently surface sensitive, elemental, and chemical specific, with the ability to probe sample surfaces under Torr level pressures. Herein, we describe the design of a new lab-based APXPS system with the ability to swap small volume analysis chambers. Ag 3d(5/2) analyses of a silver foil were carried out at room temperature to determine the optimal sample-to-aperture distance, x-ray photoelectron spectroscopy analysis spot size, relative peak intensities, and peak full width at half maximum of three different electrostatic lens modes: acceleration, transmission, and angular. Ag 3d(5/2) peak areas, differential pumping pressures, and pump performance were assessed under varying N2(g) analysis chamber pressures up to 20 Torr. The commissioning of this instrument allows for the investigation of molecular level interfacial processes under ambient vapor conditions in energy and environmental research.

A high-pressure x-ray photoelectron spectroscopy instrument for studies of industrially relevant catalytic reactions at pressures of several bars

“…The analyzer has a standard configuration 19,42 and is placed in a horizontal geometry to match the E-vector of photons generated by a synchrotron undulator. The lens tables are optimized for high transmission up to ∼9.3 keV, with little compromise for kinetic energies below 200 eV.…”

“…[10][11][12][13][14][15] These instruments often take advantage of a combination of differential pumping and an electrostatic prelens section in electron spectrometers. 8,[16][17][18][19][20][21] Apertures of several hundred micrometers in diameter are used to limit the gas flow from the high-pressure region to the differential pumping section of the analyzer. A pressure difference of several orders of magnitude is achieved between the region surrounding the sample and the first differential pumping stage.…”

Ambient Pressure Photoelectron Spectroscopy: Opportunities in Catalysis from Solids to Liquids and Introducing Time Resolution

“…A few laboratory‐based setups pioneered photoemission at elevated pressure, and a significant progress was seen when the third‐generation synchrotron radiation sources became operational . With the availability of high‐flux and micro‐focused photon sources and improved electron energy analyzers, many APXPS systems were commissioned to synchrotron beamlines, as well as within laboratories . The high X‐ray monochromatic flux obtained at synchrotron photon sources generates a higher number of photoelectrons in comparison to the anode sources, which allows acquiring good photoemission signals even after the inelastic loss experienced in the presence of a gas and even liquid.…”

“…[25][26][27] With the availability of high-flux and micro-focused photon sourcesa nd improvede lectron energy analyzers, many APXPS systems were commissioned to synchrotronb eamlines, [28][29][30][31][32][33][34][35][36] as well as within laboratories. [37][38][39][40][41][42][43][44][45] The high X-ray monochromatic flux obtained at synchrotron photon sources generates ah igher number of photoelectrons in comparison to the anode sources, which allows acquiring good photoemission signals even after the inelastic loss experienced in the presence of ag as and even liquid.A nother advantage of synchrotron sourcesi st he possibility to tune the photon energy over al arge energy range, so that depth profiles can be obtained.P resently,aw ide group of users involved in ambient pressure photoelectrons pectroscopic studies based on synchrotron as well as laboratory equippedp hoton sourcesa ffirm the successful present and ap romising future in this area.…”

Advances in liquid phase soft-x-ray photoemission spectroscopy: A new experimental setup at BESSY II

“…48, 49 A pressure of 10 -7 mbar was obtained in the lens region, and 10 -8 mbar in the MCP region, while the pressure in the IC was 5•10 -4 mbar. 50 The detection angle was set to 90° with respect to the light polarization vector. Further details are described below for each experiment.…”