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The adsorption of CO on Co(0001) has been investigated in situ by polarization modulation infrared reflection absorption spectroscopy (PM-RAIRS), which has been applied for the first time in a study of a model system for a heterogeneous catalyst. The CO/Co(0001) system was studied in the pressure range from 10 -10 to 600 mbar at temperatures between 300 and 550 K, showing the in situ potential of PM-RAIRS and the significant scope of this method for catalysis research. Linearly and bridge-bonded CO species could be distinguished on well-annealed surfaces. High-pressure RAIRS experiments done at room temperature were in agreement with previous low-energy electron diffraction (LEED) investigations in ultrahigh vacuum (UHV) at 100 K, 3,4 indicating a transition in the CO layer from a ( 3 × 3)R30°to a (2 3 × 2 3)R30°structure with increasing CO coverage. By comparison of well-annealed and Ar-sputtered (defective) surfaces, we could identify, at a high frequency of around 2080 cm -1 , a CO species attached to defect sites. It is shown that annealing at 450-490 K at 100 mbar of CO pressure leads to the creation of defects at the cobalt surface. The defects influence the structure of the CO overlayer. The nature of this "defect"-bound CO is discussed. Postreaction X-ray photoelectron spectroscopy (XPS) showed the development of surface carbide upon annealing in CO, which is in good agreement with the vanishing of the RAIRS signal of adsorbed CO at temperatures above 520 K.

The coadsorption behavior of CO and hydrogen on Co(0001) during exposure to mixtures of H2 and CO at pressures up to 300 mbar and temperatures between 298 and 490 K has been studied by in-situ polarization modulation reflection absorption infrared spectroscopy (PM-RAIRS). At 490 K it is shown that adsorbed CO molecules attached to cobalt atoms at step edges (“defect sites”) disappear. We explain this observation in terms of hydrocarbon formation at defect sites, which blocks the adsorption of CO at these positions. To support this explanation, both ex-situ X-ray photoelectron spectroscopy measurements and kinetic measurements have been performed. The kinetic measurements provide direct evidence for a link between the number of defect sites at the surface and the total Fischer−Tropsch activity.

CO‐assisted ethene insertion is the most remarkable aspect of the catalytic propagation mechanism of CO/ethene copolymerization at a microcrystalline catalyst, namely, [(dppp)Pd(CH3)(OSO2CF3)] (dppp=1,3‐bis(diphenylphosphanyl)propane). Both single propagation steps and copolymer growth (shown schematically; R represents the growing polyketone chain, the phenyl groups in dppp have been omitted) could be monitored in situ under mild, solvent‐free reaction conditions with the aid of a very sensitive IR technique, PM‐RAIRS.

Pb Zr 1 − x Ti x O 3 (PZT) is one preferred ferroelectric material being used in nonvolatile ferroelectric random access memory devices. The use of oxide electrodes like IrO2 or SrRuO3 (SRO) is necessary to suppress the serious loss of polarization due to bipolar voltage cycling. Although, there are a number of models under discussion, the origin of the fatigue phenomenon is still not completely understood. In this paper, the fatigue effect of ferroelectric Pb(Zr0.40,Ti0.60)O3 thin films has been studied in detail. To achieve a deeper understanding of the effect, several PZT samples with different electrode materials were investigated. After determining the dependence of the single fatigue parameters, a simulation approach was made to analyze the fatigue effect qualitatively. A sample with SRO electrodes was measured up to 1013cycles and no fatigue of the switchable polarization was observed.