Elementära fotokatalytiska ytprocesser på halvledande oxider
Tidsperiod: 2016-01-01 till 2019-12-31
Projektledare: Lars Österlund
Budget: 3 400 000 SEK
We aim to study molecule-surface interactions and shallow trap states on single crystal semiconducting metal oxides and thin solid film metal oxides by two main methods: infrared reflection-absorption spectroscopy (IRRAS) and ab initio calculations. A surface science – thin film hybrid approach will be used, whereby single crystal studies and thin film studies in ultra-high vacuum (UHV) are conducted in parallel to address structure gap problems encountered in heterogeneous photocatalysis. Angle and polarization dependent IRRAS of small molecule adsorption and reactions will be studies on TiO2 and Fe2O3 single crystals, and thin films grown on IR reflecting metals (TiO2, WO3, NiO, and Fe2O3), employing a home-built UHV IRRAS set-up. We will focus on the SO2, CO2 and NO2 adsorption systems, since they represent case studies which are relevant in gas-phase photocatalysis for CO2 reduction to synthetic fuels, and pollutant degradation (SO2 and NO2), but also because they can be photo-fixated to oxides and thereby used to purposefully change their acid-base properties. Furthermore, we plan to investigate shallow traps by IRRAS and cryogenic optical spectroscopy and photoluminescence by performing experiments on oxide films with controlled (O vacancy) defect concentrations and ion insertion, which will provide information of recombination mechanisms in photocatalytic oxide materials.