Combined XAS/DRIFTS, designed and built by members of the Synchrotron Catalysis Consortium, is an instrument that is available at the QAS beamline. It provides analytic tools for solving structural, electronic and kinetic problems of interests to catalytic science by two complementary methods -X-ray absorption spectroscopy (XAS) and infrared spectroscopy. XAS follows the changes of metallic catalysts during the in-situ reaction while DRIFTS simultaneously characterizes chemical species adsorbed on the catalysts as well in gas phases.

XAS data is collected in transmission mode with the one ionization chamber positioned before the IR setup to detect the intensity of incident beam while the other two ion chambers are placed right after the XAS/DRIFTS reaction chamber to obtain intensities of transmitted beam and reference signal.

DRIFTS data is obtained by coupling the Thermo Nicolet iS50 spectrometer with the Harrick DRIFTS accessories which are custom-assembled to accommodate x-ray beam path through the reaction chamber.

This instrument is coupled with the gas handling system and RGA and applied in the catalysis reactions involving both gas/solid phases.

Figure 1. Combined XAFS/DRIFTS/RGA setup

Figure 2. (a) DRIFTS and (b) Pt L3 XANES spectra during the CO adsorption onto Pt/Al2O3

The following references describe the development and application of combined XAFS-DRIFTS capabilities at the SCC:

1) N. Marinkovic, Q. Wang, A. I. Frenkel
In situ diffuse reflectance infrared spectroscopy and x-ray spectroscopy for studies of fast catalytic processes
J. Synchrotron Rad. 18, 447-455 (2011)

2) N. Marinkovic, Q. Wang, L. Barrio, S. Ehrlich, S. Khalid, C. Cooper, A. I. Frenkel
Combined in situ X-ray absorption and diffuse reflectance infrared spectroscopy: an attractive tool for catalytic investigations
Nucl. Instr. Meth. Phys. Res. A 649, 204-206 (2011)

3) A. M. Ganzler, H. Lichtenberg, A. I. Frenkel, M. Casapu, A. Boubnov, D. Wang, J.-D. Grunwaldt
Using combined XAS/DRIFTS to study CO/NO oxidation over Pt/Al2O3 catalysts
J. Phys.: Conference Series 712, 012045 (2016)