TY - JOUR
T1 - Attenuated total reflection infrared spectroscopy for studying adsorbates on planar model catalysts : CO adsorption on silica supported Rh nanoparticles
AU - Leewis, C.M.
AU - Kessels, W.M.M.
AU - Sanden, van de, M.C.M.
AU - Niemantsverdriet, J.W.
PY - 2006
Y1 - 2006
N2 - A sensitive method is presented for studying adsorption of gaseous species on metal surfaces in vacuum by attenuated total internal reflection Fourier transform IR spectroscopy (ATR). The method is illustrated by CO adsorption expts. on silica supported Rh nanoparticles. An exptl. setup and a procedure are described in detail to obtain a sensitivity of reflectance change of .apprx.5 * 10-5 absorbance units. Here, a silicon ATR crystal with a 50 nm layer of hydroxylated silica acts as the support for the Rh nanoparticles. These particles are easily prepd. by spincoat impregnation from a RhCl3 soln. followed by H2 redn. XPS before and after redn. shows that rhodium is reduced to Rh0 and that all chlorine is removed. At. force microscope images the distribution of the particles, which are 3-4 nm in height. When the crystal is exposed to pressures up to 1 mbar of CO, a gas which is inert to the silica support, the stretch vibration of linearly adsorbed CO on the Rh nanoparticles is detected at 2023 cm-1, while no bridged CO or geminal dicarbonyl species can be distinguished. The min. detectable coverage is estd. .apprx.0.005 CO per nm2 substrate area or .apprx.5 * 10-4 ML. [on SciFinder (R)]
AB - A sensitive method is presented for studying adsorption of gaseous species on metal surfaces in vacuum by attenuated total internal reflection Fourier transform IR spectroscopy (ATR). The method is illustrated by CO adsorption expts. on silica supported Rh nanoparticles. An exptl. setup and a procedure are described in detail to obtain a sensitivity of reflectance change of .apprx.5 * 10-5 absorbance units. Here, a silicon ATR crystal with a 50 nm layer of hydroxylated silica acts as the support for the Rh nanoparticles. These particles are easily prepd. by spincoat impregnation from a RhCl3 soln. followed by H2 redn. XPS before and after redn. shows that rhodium is reduced to Rh0 and that all chlorine is removed. At. force microscope images the distribution of the particles, which are 3-4 nm in height. When the crystal is exposed to pressures up to 1 mbar of CO, a gas which is inert to the silica support, the stretch vibration of linearly adsorbed CO on the Rh nanoparticles is detected at 2023 cm-1, while no bridged CO or geminal dicarbonyl species can be distinguished. The min. detectable coverage is estd. .apprx.0.005 CO per nm2 substrate area or .apprx.5 * 10-4 ML. [on SciFinder (R)]
U2 - 10.1116/1.2171707
DO - 10.1116/1.2171707
M3 - Article
SN - 0734-2101
VL - 24
SP - 296
EP - 304
JO - Journal of Vacuum Science and Technology A
JF - Journal of Vacuum Science and Technology A
IS - 2
ER -