AVS 61st International Symposium & Exhibition
    In-Situ Spectroscopy and Microscopy Focus Topic Tuesday Sessions
       Session IS+AS+MC+SS-TuM

Invited Paper IS+AS+MC+SS-TuM1
The ISISS Facility at BESSY II and Beyond: The Application of Near Ambient Pressure X-ray Electron Spectroscopy in the Surface Characterization of Technical Catalysts

Tuesday, November 11, 2014, 8:00 am, Room 313

Session: Ambient Pressure X-ray Photoelectron Spectroscopy (AP-XPS)
Presenter: Michael Hävecker, Helmholtz-Zentrum Berlin für Materialien und Energie/Elektronenspeicherring BESSY II, Germany
Authors: M. Hävecker, Helmholtz-Zentrum Berlin für Materialien und Energie/Elektronenspeicherring BESSY II, Germany
Ch. Heine, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
M. Eichelbaum, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
F. Rosowski, BasCat, UniCat-BASF JointLab, Germany
A. Trunschke, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
R. Schlögl, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany
Correspondent: Click to Email

The surface of functional materials like catalysts responds to the ambient conditions. Surface sensitive in-situ spectroscopy, i.e. in the presence of a reactive gas allows studying the formation of the gas/solid interface of a catalyst. The ISISS facility operated by the FHI at the synchrotron radiation source BESSY II of the HZB is dedicated to this kind of in situ studies [1 - 3]. Online gas analytics allows correlating the electronic surface structure with the catalytic performance. Examples for the dynamic formation of the electronic surface structure by interaction with the ambient gas under equilibrium will be presented focusing on technical catalysts like multi-element mixed oxide powders. The direct catalytic oxidation of alkanes to olefins and oxygenates is becoming increasingly important for the chemical industry due to the up-coming shortage of crude oil resources. Vanadyl pyrophosphate is the industrially used catalyst in the selective oxidation of n-butane to maleic anhydride. We characterized the surface of this catalyst material with NAP-XPS in the mbar pressure range and with NAP-soft XAS in the electron yield mode at pressures up to 1000mbar at various gas mixtures. In addition to the determination of composition and vanadium oxidation state also semiconductor properties like work function changes and Fermi level pinning have been studied [4].

Finally, an outlook on future activities at HZB/BESSY to develop further synchrotron based ambient pressure characterization methodologies will be given. The Energy Materials In-Situ Laboratory Berlin (EMIL) is a research alliance of the HZB and FHI that will include a NAP-high kinetic energy XPS endstation capable to operate at kinetic energy of photoelectrons up to 7000eV that allows studying buried layers and liquid/solid interfaces.

References

  1. Salmeron, M., Schlögl, R., Ambient pressure photoelectron spectroscopy: A new tool for surface science and nanotechnology. Surf. Sci. Rep., 32, 1022 (2008).
  2. Bluhm, H., Hävecker, M. et al., In situ x-ray photoelectron spectroscopy studies of gas-solid interfaces at near ambient conditions, MRS BULLETIN., 63, 169 (2007).
  3. Bluhm, H. et al., Investigation of solid/vapor interfaces using ambient pressure X-ray photoelectron spectroscopy. Chem. Soc. Rev., 42, 5833 (2013).
  4. Heine, Ch. et al., Work function, band bending, and microwave conductivity studies… J. Phys. Chem. C, 117, 26988 (2013).