Catalysator element comprised of a mixed metal oxide hydrotacite-like compound

The present invention relates to a catalysator element comprising a mixed metal oxide compound for conversion of nitrogen oxides (NOx). The present invention further relates to methods for the preparation of the present mixed metal oxide compound for use in the present catalysator element and to exhaust systems for a combustion engine comprising the present catalysator element for conversion of (NOx) in exhaust gasses. Specifically, the present invention relates to a catalysator element for conversion of nitrogen oxides (NOx) comprised of a solid support coated with a calcined mixed metal oxide hydrotalcite-like compound, wherein said calcined mixed metal oxide hydrotalcite-like compound comprises at least one bivalent metal (M2+) and at least one trivalent metal (M3+).info:eu-repo/semantics/publishe

Attempts at an in-situ Raman study of Ceria / Zirconia catalysts in PM combustion

CexZr1−xO2 catalysts with various Ce/Zr contents were studied using Raman spectroscopy under different gaseous atmospheres, at different temperatures and in the presence of a model soot. Catalysts with high concentrations of Zr fluoresced at elevated temperatures making analysis of their spectra impossible. This effect became even more pronounced at higher temperatures. CeO2 and solid solutions with relatively low concentrations of Zr showed a red shift and a decrease in intensity of the characteristic F2g peak at high temperatures under different atmospheres. The magnitude of the latter effect was higher under reducing atmospheres. These changes are reversible upon cooling, showing that they relate to a lattice expansion effect rather than any major chemical change to the material. In the presence of the model soot the Raman spectra of all materials was much decreased due to the absorption of the incident and scattered radiation by the soot particles. The presence of soot does not change the relative intensities or positions of the peaks in the spectra of the solid solutions. Evidence is shown for the production of a Ce3+–CO species following interaction between the soot and the surface at high temperature in an inert atmosphere.DG 15/11/1

On the activation of methane and carbon dioxide at room temperature using cobalt oxide catalysts

info:eu-repo/semantics/nonPublishe

Identification key for adhesives used in conservation of ceramics and glass

During conservation-restoration treatments the conservator is often confronted with works that have already been treated. Generally, these previous interventions are not documented and the conservator needs to identify previously used materials to apprehend the object’s material history and to orient conservation treatments.Instrumental methods can be used to precisely identify the chemical nature of these materials. However, they require expensive analytical instruments which are usually only available within scientific research institutions. Microchemical spots tests, taken from qualitative analytical chemistry, have been made available to conservators as an alternative solution. These methods are extensively used to approach the nature of pigments, charges and binders, commonly found in art objects. The identification of historical and contemporary adhesives has been scarcely addressed in the scientific literature. Simple physicochemical tests, sometimes coupled to spot tests, have been used. Nonetheless, these methodologies do not systematically include the entire range of available test tools as to produce a broader, general approach allowing to accurately discriminate larger numbers of adhesives.The identification key proposed in this research is easy and inexpensive to use by conservators in their private workshop. The identification key was tested on various samples taken from ceramics museum objects (see practical cases) and proved that this identification key can be successfully employed on naturally aged adhesives.However we found that some parameters changed over time, such as appearance and fluorescence that’s why we based our research on more objective characteristics. It would be interesting to continue this research by studying the influence of aging on the response of adhesives to different identification key analyses.In a second time to observe the influence of other factors such as fillers and/or pigments added in some adhesives.info:eu-repo/semantics/publishe

The effect of C(s) on the trapping of NOx onto Pt/Ba/Al2O3 catalysts

Pt/BaO/Al2O3 catalysts react with NO/O2 mixtures to form barium nitrites and nitrates. In the presence of small amounts of C(s) admixed with the catalyst the concentrations of NOx adsorbed is considerably reduced and the stability of the stored NOx is decreased. These results suggest that there are important implications for any attempts to combine NSR and particulate combustion systems within a single catalytic system. Furthermore, it is clear that there are significant concentrations of mobile NOx species present in the environs of the NOx trap prior to fixation on BaO, i.e. the transfer between NO2 formed on the Pt component of the trap and the “fixed” NOx in Ba(NO3)2 involves significant concentrations of gaseous or surface mobile NO2.DG15/11/1