Characterization of Metal-Oxide Catalysts in Operando Conditions by Combining X-ray Absorption and Raman Spectroscopies
- PDF / 605,704 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 92 Downloads / 188 Views
ORIGINAL PAPER
Characterization of Metal-Oxide Catalysts in Operando Conditions by Combining X-ray Absorption and Raman Spectroscopies in the Same Experiment A. Patlolla • P. Baumann • W. Xu • S. D. Senanayake J. A. Rodriguez • A. I. Frenkel
•
Published online: 18 May 2013 Ó Springer Science+Business Media New York 2013
Abstract We have developed a new instrumental setup that combines simultaneous X-ray absorption spectroscopy, Raman spectroscopy and online mass spectrometry for operando studies of catalytic reactions. The importance of combining these techniques in the same experiment is demonstrated with the example of CO oxidation over nanoscale copper oxide catalysts supported on high surface area titanium oxide. X-ray absorption near edge structure (XANES) spectroscopy provides information on the charge state and local geometry of the catalytically active atoms. Extended X-ray absorption fine-structure (EXAFS) technique adds information about their local coordination environment. Raman spectroscopy adds sensitivity to crystallographic phase and long range order that both XANES and EXAFS are lacking. Together, these measurements enable simultaneous studies of the structural and electronic properties of all components present in metaloxide catalysts. Coupled with online reactant and product analysis, this new setup allows one to elucidate the synergy between different components of a catalytic system and shed light on its catalytic activity and selectivity.
A. Patlolla P. Baumann A. I. Frenkel (&) Physics Department, Yeshiva University, 245 Lexington Avenue, New York, NY 10016, USA e-mail: [email protected] P. Baumann University of Applied Sciences of Northwestern Switzerland, 4132 Muttenz, Switzerland W. Xu S. D. Senanayake J. A. Rodriguez Department of Chemistry, Brookhaven National Laboratory, Upton, NY 11973, USA
123
Keywords Multi-technique characterization Operando studies Metal Oxide catalysts Oxygen reservoir
1 Introduction Transition metal oxide-supported catalysts are among the most ubiquitous catalytic systems commonly used [1–6]. Despite significant progress made in developing catalysis theories where completely [7] or partially [8, 9] reduced oxides play a central role in the catalytic process, the role of the oxide support is relatively less understood. One of the main challenges towards a more objective investigation is the need to study all components of metal-oxide catalysts in the same conditions, which is difficult to accomplish when different techniques are used. Within the field of spectroscopy alone, a large number of techniques such as XAS [10], NMR [11], EPR [12], IR [13], Raman [14] and UV–VIS [15] have already been adapted to study metaloxide catalysts under reaction conditions, providing complementary information about the catalytic process and structure of the catalyst. However, the challenge remains in the co-interpretation of their results since these methods are commonly applied in separate setups to the samples exposed to different experimental conditions
Data Loading...
