Berlin 2018 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 53: Energy materials (other than photovoltaics)
HL 53.6: Talk
Friday, March 16, 2018, 10:45–11:00, EW 202
Activating CO2 for photocatalytic reduction at the semiconductor surface — •Veronika König, Peter Budweiser, Jacek Stolarczyk, and Jochen Feldmann — Chair for Photonics and Optoelectronics, Department of Physics, Ludwig-Maximilians-Universität, Munich, Germany
In modern photocatalysis sunlight is used to convert water or carbon dioxide into solar fuels like molecular hydrogen or methane. Semiconductor materials thereby serve as the catalyst and reaction site. They absorb the sunlight, separate electron-hole pairs and transfer the charges to the respective molecules triggering electrochemical reactions that ultimately lead to the formation of the desired solar fuels.
Compared to water splitting CO2 reduction is even more challenging due to the high stability of the CO2 molecule. The reduction potential for the initial placement of an electron on the CO2 is much more negative than the potential of the conduction band edges of most known semiconductor materials, making appropriate catalysts rare.
Copper (I) compounds such as Cu2S have been found to be promising candidates for CO2 reduction[1] and were shown by our group to produce CH4 and CO[2]. Here, we use Cu2O nanocrystals ranging from 10 to 100 nm in size in combination with ZnO for better charge separation. We investigate ways to increase the efficiency of photocatalytic CO2 reduction by activation of the CO2 molecule at the nanocrystal surface to lower the barrier for the initial one-electron reduction.
[1] Habisreutinger, S., et al. Angew. Chem. Int. Ed. 2013, 52, 7372
[2] Manzi, A., et al. J. Am. Chem. Soc. 2015, 137, 14007