Chemistry Department Seminar

"In situ Studies and Gas Phase Visulation of Model Catalysts at Work"

Presented by Prof. Edvin Lundgren, Institute of Physics, Lund University, Sweden

Wednesday, January 31, 2018, 11:00 am — Hamilton Seminar Room, Bldg. 555

Motivated mainly by catalysis, gas-surface interaction between single crystal surfaces and molecules has been studied for decades. Most studies have been performed in well-controlled environments, and has been instrumental for the present day understanding of catalysis. We have for some years explored the possibilities to perform experiments at conditions closer to those of a technical catalyst, in particular at increased pressures. In this contribution we will show examples from catalytic CO oxidation over Pd single crystal surfaces using Ambient Pressure X-ray Photo emission Spectroscopy (APXPS) [1] and High Energy Surface X-Ray Diffraction (HESXRD) [2] at more realistic conditions. However, the detected surface structure during the reaction is sensitive to the composition of the gas phase close to the catalyst surface [3-4]. Therefore, the catalytic activity of the sample will itself affect the surface structure, which may complicate the assignment of the active phase. For this reason, we have applied 2D Planar Laser Induced Fluorescence (PLIF) to the gas phase in the vicinity of an active model catalysts [5-7]. In particular, these measurements enables a direct view of the onset and location of the catalytic activity. Further, the gas phase distribution during a catalytic reaction from more complicated samples, such as a curved single crystal upon ignition [8] may be explored, see Fig. 1.

[1] S. Blomberg et al; Phys. Rev. Lett. 110, 117601 (2013).
[2] J. Gustafson et al; Science, 343, 758 (2014).
[3] S. Matera and K. Reuter, Phys. Rev. B 82, (2010) 085446.
[4] S. Matera et al; ACS Catalysis 5, 4514 (2015).
[5] J. Zetterberg et al; Rev.Sci. Instrum. 83, 053104 (2012).
[6] J. Zetterberg et al; Nat. Comm. 6, 7076 (2015).
[7] S. Blomberg et al; ACS catalysis 5, 2028 (2015).
[8] S. Blomberg et al; ACS Catalysis 7, 110 (2016).

Hosted by: Sanjaya Senanayake

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