We synthesised a manganese-modified thermally stable mesoporous silica-based catalyst MnMCM-41. Pores of this material have diameter of about 2 nm and are sufficiently large that the material could be employed in catalysis of bulkier molecules. We used several spectroscopic techniques to determine the nature and the location of the catalytically active sites. The determined catalytic properties are due to manganese incorporated into the framework. Manganese does not leach from the framework, which means that the catalyst could be recycled.
COBISS.SI-ID: 3265050
We synthesised a new microporous/mesoporous composite material (Ti,Al)-Beta/MCM-48, which combines good catalytic properties and thermal stability of the microporous and large pores of the mesoporous material. In the first step we developed a procedure for the incorporation of titanium cations into zeolitic nanoparticles. In the second step these nanoparticles were arranged into the mesoporous matrix, what yielded a composite material with higher hydrothermal stability than the parent mesoporous MCM-48 material.
COBISS.SI-ID: 3636250
In SBA-15 pores are larger and walls are thicker than in mesoporous materials of the MCM family. Therefore, instead of organizing microporous nanoparticles into mesoporous structures, we were able to simply deposit tiny zeolitic grains into the pores of the pre-synthesized SBA-15. Such a composite material has some advantages: (i) its preparation is simple (ii) metal-modified microporous nanoparticles within mesopores are easily accessible, (iii) diffusion of molecules slows down in the vicinity of the zeolitic grain, which increases the catalytic efficiency.
COBISS.SI-ID: 4066074
In mesoporous aluminophosphate materials pores are usually arranged in a hexagonal stack. Such pores are all parallel and because they all point into the same direction, the interior of the material is in practice poorly accessible to molecules. We prepared two cubic aluminophosphate materials with pores running along three mutually orthogonal axes. Because of different pore arrangement and because of their 10 nm large diameters, the materials are very promising. Moreover, the materials were not only prepared as powders but also as thin films with the thickness of about 500 nm.
COBISS.SI-ID: 3950362
We presented an efficient method for studying proximities between dipolar-coupled half-integer quadrupolar nuclei. The method is based on the resonance between the strength of the radiofrequency magnetic field and the spinning speed of the sample. Performance of the method was demonstrated on AlPO4-14, in which aluminium nuclei have diverse quadrupolar coupling constants and isotropic shifts, and different distances to nearest neighbours. We have shown that the method was robust and that it allowed quantitative analysis of distances among quadrupolar constituents.
COBISS.SI-ID: 2978842