Evaluation of the reactivity, selectivity and lifetime of hydrotalcite-based catalysts using isopropanol as probe molecule

Hydrotalcite catalysts derived from NiAl and NiAlMg mixed oxides were successfully prepared by coprecipitation at a constant pH of 11. Physicochemical methods were investigated to determine their structural and textural properties. Using isopropanol as a probe molecule, the acid–base properties of the catalysts were investigated, and the evaluation of reactivity, selectivity and lifetime was established.

Ag-Decorated Polymer Chip for the Determination of the Respective Concentrations of TTD and Hg2+ by Surface-Enhanced Raman Scattering

The “hotspot”-rich Ag-nanoparticles-decorated three-dimensional polymer substrate was fabricated, exhibiting an excellent surface-enhanced Raman scattering (SERS) activity. 4-mercaptobenzoic acid was selected as a probe molecule for comparing SERS activity on selected...

Nitrogen as a Probe Molecule for the IR Studies of the Heterogeneity of OH Groups in Zeolites

One of the methods of IR studies of the heterogeneity of Si–OH–Al groups in zeolites is the investigation of the frequency shift of the band of free OH bands restored upon the adsorption of ammonia and subsequent desorption at increasing temperatures. We extended this method by following the shift of the band of the OH group interacting by hydrogen bonding with nitrogen. The advantage of nitrogen, compared with CO, which has been commonly used as a probe molecule in studies on hydrogen bonding, is that for nitrogen the frequency shift is smaller than for CO and therefore there is no overlapping of shifted OH band with the bands of ammonium ions. For zeolites NaHY, HMFI, and HBEA, the frequency shift of IR bands of both free and hydrogen-bonded Si–OH–Al with the increase of ammonia desorption temperature evidences the heterogeneity of these hydroxyls. On the other hand, in zeolite HFAU of Si/Al = 31, Si–OH–Al were found to be homogeneous. Heterogeneity of OH groups may be explained both by the presence of Si–OH–Al of various number of Al near the bridge and of Si–OH–Al of various geometry.

Recent Advances in Coherent Anti-Stokes Raman Scattering of Carbon Dioxide for Combustion Diagnostic. (Article Review)

The rising climatic degradation due to the emission of greenhouse gases is leading to emergence of clean combustion technology, oxy-fuel combustion to minimize the emissions of carbon dioxide into the atmosphere in combustion. Nitrogen molecules are used as probe molecule in laser-based combustion diagnostic in nitrogen rich air combustion. However, with the introduction of oxy-fuel combustion, carbon dioxide becomes the dominant molecule and has to be considered as probe molecule in combustion diagnostic. A detailed knowledge about thermodynamic properties: temperature, pressure and species concentration are necessary in optimization of combustion and minimizing the emission into the atmosphere. The non-intrusive spectroscopic measurement techniques are the most accurate methods to determine the combustion properties. The purpose of this review is to provide a brief overview of the recent advances made in application of coherent anti-Stokes Raman scattering of carbon dioxide for development of models for thermometry. However, there is no sufficient empirical data of time-domain S-branch Raman linewidth dependence on temperature that has been determined for pure-rotational coherent anti-Stokes Raman scattering of carbon dioxide and its mixtures for development of models for thermometry.

CO adsorption on the calcite(10.4) surface: a combined experimental and theoretical study

Information on structural, chemical and physical properties of natural cleaved (10.4) calcite surfaces was obtained by a combined atomic force microscopy and infrared study using CO as a probe molecule under ultrahigh vacuum conditions.