The Effect of Nb Loading on Catalytic Properties of Ni/Ce0.75Zr0.25O2 Catalyst for Methane Partial Oxidation

In this study,the effect of Nb loading on the catalytic activity of Ce_(0.75)Zr_(0.25)O_2-supported Ni catalysts was studied for methane partial oxidation.The catalysts were characterized by BET,H_2 chemisorption,XRD,TPR,TEM and tested for methane partial oxidation to syngas in the temperature range of 400-800℃at atmospheric pressure.The results showed that the activity of methane partial oxidation on the catalysts was apparently dependent on Nb loading.It seemed that the addition of Nb lowered the catalytic activity for methane partial oxidation and increased the extent of carbon deposition. This might be due to the strong interaction between NiO and Nb-modified support and reduction of surface oxygen reducibility.     

Einführung in prädikatives und funktionales Denken

A particular interest for invariances on the one hand and variability on the other hand as seen in sationary and moving objects respectively has often led people to more or less severe disagreements. The notions of «predicative thinking» versus «functional thinking» describe a cognitive pattern that tries to explain the preference or even special capability for either one of the two view points. Meanwhile, there are not only numerous qualitative experimental results that prove the usefulness of this theoretical construct, but also an EEG-study and several studies involving eye-movement analysis that emphasise quantitative evidence. As aspects of predicative thinking have been studied quite frequently in cognitive psychology, there is an accumulated need for studies of functional thinking. Primary school education shows that functional approaches have been neglected in spite of advocates of the operational principle. Anyhow, there are didactical materials like the Addition-, Multiplication-Landscape, the spiral staircase for calculating or the Dynamic Labyrinths that are very well suited to demand and promote functional thinking.     

TPR Investigation of bimetallic Ru-Cu samples supported on SiO2, Al2O3 and MgO

Journal of Thermal Analysis and Calorimetry - Bimetallic Ru-Cu samples supported on SiO2, Al2O3 and MgO were studied by the temperature-programmed reduction (TPR) technique. Experiments were...     

Polypyrrole/poly(methylmethacrylate) blend as selective sensor for acetone in lacquer

A film of α-naphthalene sulfonate-doped polypyrrole/poly(methylmethacrylate), PPy/α-NS⁻/PMMA, obtained from solution mixing was successfully used as sensing material for acetone vapor in lacquer with a high degree of selectivity based on electrical conductivity over acetic acid and a high degree of stability over the humidity change. Compared with pure PPy/α-NS⁻, the selectivity ratio of acetone/acetic acid response of PPy/α-NS⁻/PMMA blend with a PMMA/PPy weight ratio of 3.0 was ca. 3.9 times higher. The film was found to be insensitive to moisture unless the relative humidity (RH) was lower than 20% RH in which the selectivity ratio of acetone/acetic acid response was enhanced. The time required to reach the equilibrium for acetone exposure was found to increase slightly with increasing humidity.     

Prädikative versus funktionale Denkvorgänge beim Konstruieren von Algorithmen

Seen from a historical point of view, two approaches to the formation of mathematical knowledge can be distinguished: classical Greek substantiated inferential knowledge and ancient oriental functional knowledge. As might have been expected, both approaches are not equally well-suited to develop and handle particular concepts. Bateson’s analysis of the term «switch» exposes only fundamental functional features but no predicative ones. Consequently, there is a special demand for functional cognitive activities when solving problems that involve the use and control of the functioning of switching constituents. Within the framework of the DFG-project “Individual differences in the cognition of mathematical concept formation”, the ability of subjects to construct machines that carry out organisational or computational tasks with the help of given mechanical switches and additional connective building blocks have been tested. The construction procedures show pronounced differences. Furthermore, the case or difficulty to get involved with the planning and realisation of the process are reflected in the verbal protocols of the subjects. Their mental attitude corresponds nicely to their behaviour when working on logical problems as they appear in the QuaDiPF-tasks. For the machines see also: http://www.ikm.uos.de/oktivitaeten/dl/dynamic_labyrinths/dynamic-labyrinths.html     

Untersuchungen über Acetate von Elementen der V. Hauptgruppe des Periodensystems

The acetates M(CH₃COO)₃ with M = P, As, Sb, Bi, and MOCH₃COO with M = Sb, Bi have been prepared. These compounds were characterised by different methods.     

Controlling carbon surface chemistry by alloying: carbon tolerant reforming catalyst

Steam reforming is a process where a hydrocarbon is converted into hydrogen and oxygenated carbon species. Ni is often used as catalyst for the reaction. Long term stability of steam reforming catalysts is governed by their ability to selectively oxidize C atoms while preventing C-C bond formation. In this communication we demonstrate that C atom chemistry over Ni surfaces can be controlled by surface alloying. We show that bimetallic Sn/Ni catalyst is much more carbon-tolerant that monometallic Ni. The main reason for this is that Sn alloying results in dramatically lower rates of C-C bond formation as compared to C-oxidation. The bimetallic catalyst was identified in quantum computational studies of the underlying atomic-scale phenomena that govern C atom surface chemistry. The catalysts were also characterized with various electron- and X-ray-based microscopies and spectroscopies.