AVS 59th Annual International Symposium and Exhibition
    In Situ Microscopy and Spectroscopy Focus Topic Tuesday Sessions
       Session IS+AS+SS+EN-TuM

Invited Paper IS+AS+SS+EN-TuM10
Catalyst Characterization using In Situ XAS and XPS: From Nanoparticles Synthesis to Evolution of Structural/Electronic Properties under Reaction Conditions

Tuesday, October 30, 2012, 11:00 am, Room 007

Session: In Situ Spectroscopic Studies of Catalysis and Gas-Solid Reactions
Presenter: A.M. Karim, Pacific Northwest National Laboratory
Correspondent: Click to Email

Catalysts are used to facilitate the important industrial chemical processes, leading to products valued in the trillions of dollars annually just in the U.S and most catalysts used in large-scale processes are solids. To maximize the number of sites available for reaction, catalysts are typically comprised of metallic/metal oxide nanoparticles dispersed on high surface area supports. The activity and selectivity of metallic nanoparticles strongly depend on their size, shape and composition [1-8]. In order to design more active and selective catalysts, it is essential to identify the catalytically active sites and understanding their geometric and electronic properties which requires: (1) synthesis of well-defined catalyst structures and (2) the ability to correlate individual reaction pathway(s) with the type of active site(s) available on the catalyst surface under reaction conditions.

This talk is going to cover our work on in situ characterization of nanoparticles from the synthesis stage to the evolution of their structural/electronic properties under reaction conditions using X-ray photoelectron and X-ray absorption spectroscopies. The catalyst systems that will be covered include:
  1. Pd nanoparticles synthesis in solution: Understanding the nucleation and growth mechanisms.
  2. Supported Pt, PtRe and PtNi nanoparticles under aqueous phase reaction condition: Correlating the structural and electronic properties with the catalytic activity and selectivity.
References:

[1] Boudart, M. Adv. Catal. 1969, 20, 153.

[2] Boudart, M. Journal of Molecular Catalysis 1985, 30, 27.

[ 3] Ichikawa, S.; Poppa, H.; Boudart, M. Journal of Catalysis 1985, 91, 1.

[4] Somorjai, G. A.; Carrazza, J. Industrial & Engineering Chemistry Fundamentals 1986, 25, 63 [ 5] Liu, Z.; Hu, J. E.; Wang, Q.; Gaskell, K.; Frenkel, A. I.; Jackson, G. S.; Eichhorn, B. Journal of the American Chemical Society 2009, 131, 6924.

[6] Alayoglu, S.; Nilekar, A. U.; Mavrikakis, M.; Eichhorn, B. Nature Materials 2008, 7, 333.

[7] Sinfelt, J. H. Journal of Catalysis 1973, 29, 308.

[8] Sinfelt, J. H. Accounts of Chemical Research 1977, 10, 15.