Sebastian Pfaff^a, Alfred Larsson^a, Lisa Rämisch^a, Sabrina Gericke^a, Edvin Lundgren^a and Johan Zetterberg^a
aLund University, Sölvegatan 14, Lund, Sweden

The switch to more in-situ studies of surface-gas interactions at high pressures has sparked an interest in further development of surface sensitive techniques that operate at higher pressures. Most of these techniques, however, such as ambient pressure XPS (AP-XPS), High-Pressure Surface Tunneling Microscopy (HP-STM) or High Energy Surface X-Ray Diffraction (HESXRD) require complex experimental setups.

In this work, show a simple setup for Surface Optical Reflectance (SOR) which can be used as an indicator of surface roughness and level of oxidation[1] in operando conditions. By using a microscope, one can even image the oxidation of separate surface domains in-situ, given that the sample is polycrystalline, which can be useful for simultaneous characterisation of multiple rotational domains[2]. The results can then be compared to those obtained though simultaneous measurements with HESXRD, which in a way provides a “calibration” to map reflectivity changes to oxidation and roughness[3].

Acknowledgements

We would like to acknowledge funding from the Swedish Research Council (Vetenskapsrådet), the Swedish Foundation for Strategic Research (Stiftelsen för strategisk forskning) as well as the Knut and Alice Wallenberg Foundation.

References

1. Onderwaater, W. G. et al. From dull to shiny: A novel setup for reflectance difference analysis under catalytic conditions. Rev. Sci. Instrum. 88, 23704 2017.
2. Suchorski, Y. & Rupprechter, G. Heterogeneous Surfaces as Structure and Particle Size Libraries of Model Catalysts. Catal. Letters 148, 2947–2956 2018.
3. Pfaff, S. et al. Combining high-energy X-ray diffraction with Surface Optical Reflectance and Planar Laser Induced Fluorescence for operando catalyst surface characterization. Rev. Sci. Instrum. 90, 033703 2019.