Fundamental surface science studies of photon and electron stimulated reactions in heterogeneous catalysis

The group has a strong research activity on the surface science of heterogeneous (photo)catalytic surface reactions and methods to activate wide band gap metal oxides to change their physicochemical properties. The group explores facet dependent photo-reactivity, adsorption and coordination of small molecules such as SO2, NO2, CO2, HCOOH and CH3COOH, and photo-induced surface reactions on transition metal oxides. A current theme involves solid super acids by means of surface modified metal oxides with sulphate ions e.g., SO4-2-TiO2, SO4-2-MnO2 and SO4-2-ZrO2 by selective reduction of surface cations (Fig. 1a). A cornerstone of the work is operando infrared and Raman spectroscopy to study adsorbate coordination and surface reactions, detailed characterization of electronic and optical properties, and micro-kinetic modelling and quantum chemical calculations (Fig. 1b).

Figure 1: Titania can be made super-acid by means of an electron-attachment mechanism induced by bandgap illumination in presence of diluted (ppm-level) SO2 gas, leading to formation of strongly bonded sulfate groups (-SO4) on the TiO2 surface [2]. (b) Condensation reaction for acetaldehyde on the TiO2 surface studied by operando FTIR spectroscopy unraveling a dimer acetaldehyde species, and a general reaction scheme for acetaldehyde condensation on TiO2 surfaces [8].

[1] L. Österlund, “Pressure gaps in heterogeneous catalysis”. In: Heterogeneous Catalysts: Advanced Design, Characterization and Applications (2021), Teoh, Urakawa, Ng and Sit (Eds.): Wiley-VCH GmbH (2021). ISBN: 978-3-527-34415-4
[2] D. Langhammer, J. Kullgren and L. Österlund, Photo-Induced Adsorption and Oxidation of SO2 on Anatase TiO2(101), J. Am. Chem. Soc. 142, 52, 21767–21774 (2020).
[3] David Langhammer, Jakob, Thyr, Lars Österlund, Surface properties of reduced TiO2 nanoparticles investigated by selective SO2 adsorption: A DRIFTS and Raman spectroscopy study, J. Phys. Chem. C 123, 24549−24557 (2019).
[4] D. Langhammer, J. Kullgren, P. Mitev, and L. Österlund, SO2 adsorption on rutile TiO2(110): An infrared reflection-absorption spectroscopy and density functional theory study, Surf. Sci. 677,46–51 (2018).
[5] B. I. Stefanov, G. A. Niklasson, C.G. Granqvist, L. Österlund, Gas-phase photocatalytic activity of sputter-deposited anatase TiO2 films: Effect of <001> preferential orientation, surface temperature and humidity, J. Catal. 335 (2016) 187–196.
[6] B. I. Stefanov, G. A. Niklasson, C. G. Granqvist, L. Österlund, Quantitative relation between photocatalytic activity and degree of 〈001〉 orientation for anatase TiO2 thin films, J. Mater. Chem. A 3 (33), 17369-17375 (2015).
[7] A. Mattsson, S. Hu, K. Hermansson, and L. Österlund, Adsorption of formic acid on rutile TiO2 (110) revisited: An infrared reflection-absorption spectroscopy and density functional theory study, J. Chem. Phys. 140, 034705 (2014).
[8] B. Stefanov, Z. Topalian, C.-G Granqvist, and L. Österlund, Influence of dimeric acetaldehyde adsorption on the acetaldehyde condensation kinetics on the anatase (101) surface, J. Mol. Catal A: Chemical 381, 77– 88 (2014).
[9] A. Mattsson and L. Österlund, Photocatalytic degradation of acetone and acetic acid on anatase, brookite and rutile TiO2, J. Phys. Chem. C 114, 14121 (2010).
[10] L. Österlund, Structure-Reactivity Relationships of Anatase and Rutile TiO2 Nanocrystals Measured by In Situ Vibrational Spectroscopy, Solid State Phenomena 162, 203-219 (2010).
[11] L. Österlund, “Vibrational spectroscopy of pure and doped TiO2 photocatalysts”. In: On Solar Hydrogen and Nanotechnology (Ed.) L. Vayssieres, Wiley & Sons, Singapore (2009). ISBN-10: 0819464198.
[12] T. van der Meulen, A. Mattsson, and L. Österlund, A comparative study of the photocatalytic oxidation of propane on anatase, rutile, and mixed-phase anatase–rutile TiO2 nanoparticles: Role of surface intermediates, J. Catal. 251, 131-144 (2007).
[13] A. Mattsson, M. Leideborg, K. Larsson, G. Westin, and L. Österlund, Adsorption and solar light decomposition of acetone on anatase TiO2 and niobium doped TiO2 thin films, J. Phys. Chem. B 110, 1210 (2006).

Last modified: 2022-03-15