From model- to real catalysts operated at relevant process conditions
- Anja Olafsen Sjåstad (University of Oslo, Norway)
- Wednesday 1 April 2020
- Hotel NH Noordwijk Conference Centre Leeuwenhorst
In our research group, we merge classical catalysis and surface science in order to close the temperature-, pressure- and materials gap through an approach based on operando studies of well-defined 2D/3D catalysts in order to reveal the fundamentals of active and living catalyst surfaces.
The main challenge in providing a suited model catalyst is to achieve an appropriate nanostructure (with a specific particle size, chemical composition, element distribution and atomic arrangement) that contains the key ingredients of the real catalyst, and at the same time provides a material that is suited for the analysis probe in question. I.e., geometrically we require 3D-powders and 2D-surfaces that are thermally and chemically stable during the experiment, likewise that the material can withstand a high-energy electron (or X-ray) beam, is sufficiently conductive and maintains the appropriate chemical state during the investigation. Ideally, all such performance studies of heterogeneous catalysts should be done at the real process conditions with respect to reaction temperature, total pressure and linear gas velocity. Fortunately, there is a tremendous development of operando instrumentation working at process relevant conditions. Examples are Near Ambient Pressure X-ray Photoelectron Spectroscopy (NAP-XPS), operando sub-Ångström (Å) resolution Transmission Electron Microscopy (TEM) and High Pressure Reactor Scanning Tunnelling Microscope (HP Reactor STM), along with rapid developments in computational materials science.
In this talk, we present some of our recent work on the preparation of model materials and their use in operando studies connected to the Fischer-Tropsch process, ammonia oxidation and NOx abatement.
- “Inversion of Selectivity in Ammonia Oxidation over Pt-Rh/Pt(111) Surfaces Studied by Ambient Pressure XPS”, O. Ivashenko, N. Johansson, C. Pettersen, M. Jensen, J. Zheng, J. Schnadt, A. O. Sjåstad, in preparation.
- “Controlled Alloying of Pt-Rh Nanoparticles by the Polyol Approach”, S. Bundli, P. Dhak. A.E. Gunnæs, P. D. Nguyen, H. Fjellvåg, A. O. Sjåstad, J. Alloys and Compounds, 779, 879, 2019.
- “Roadmap for Modeling RhPt/Pt(111) Catalytic Surfaces for Intermediate-Temperature Ammonia Oxidation", J. Zheng, O. Ivashenko, H. Fjellvåg, I. Groot, A. O. Sjåstad, J. Phys. Chem. C, 122(46), 26430, 2018.
- “The nucleation, alloying, and stability of Co-Re bimetallic nanoparticles on Al2O3/NiAl(110)”, R. V. Mom, O. Ivashenko, J. W. M. Frenken, I. M. N. Groot, A. O. Sjåstad, J. Phys. Chem. C 122, 8967, 2018.
- “In situ TEM observation of the Boudouard reaction: multi-layered graphene formation from CO on cobalt nanoparticles at atmospheric pressure”, M. Bremmer, E. Zacharaki, A. O. Sjåstad, V. Navarro, J. Frenken, P. Kooyman, Faraday Discussions, 197, 337, 2017.
- “Hot injection method for size controlled synthesis of -cobalt nanoparticles”, E. Zacharaki, M. Kalyva, H. Fjellvåg, A. O. Sjåstad, Chemistry Central Journal, 10, 10, 2016.