Section Days abstract book 2010.indd - RUB Research School ...

NSE_06
ADSORPTION AND OXIDATION OF METHANOL ON
PERFECT AND DEFECTIVE ZnO SURFACES
Physical Chemistry I
Ruhr-University Bochum, 44780, Germany
email: Lanying.Jin@rub.de
Lanying Jin, Henshan Qiu and Yuemin Wang
Zinc oxide has attracted much research interest due to its particular electronic, optical and
catalytic properties[1]. In catalysis, Cu/ZnO is the standard catalyst for the industrial
methanol synthesis. So far, it is not fully understood how Cu/ZnO catalyst works for methanol
synthesis and its stream reforming. Therefore, studies of the interaction of methanol with ZnO
are of fundamental importance in understanding the relevant catalytic processes on atomic
scale. In this work, we report on the adsorption and oxidation of methanol on the perfect and
defective non-polar ZnO(10-10) surfaces by high-resolution electron energy loss spectroscopy
(HREELS) and thermal desorption spectroscopy (TDS). Exposing the perfect ZnO(10-10)
surface to methanol at room temperature leads to partial dissociative adsorption forming
methanol and methoxy species. After heating to high temperatures most of the adsorbates
desorb molecularly and only a small amount of methoxy species undergoes selective
oxidation to CH2O at 570 K and complete oxidation to CO, CO2 and H2 at 595 K. It is found
that this surface becomes more active after creating Zn-O dimer vacancies by controlled argon
sputtering. The dominant feature is methoxy decomposition yielding CO, CO2 and H2 at 595
K, which is totally different from the results on perfect surfaces. In addition, the formation of
formate species is also identified on the defective ZnO(10-10) surface by HREELS. Finally,
the results on ZnO single crystals are compared with those on ZnO nanoparticles obtained by
UHV-FTIR spectroscopy.
References:
[1] Ch. Wöll, Prog. Surf. Sci. 82 (2007) 55.