Hybrid catalysts for polymerization of acetylenes were prepared by anchoring, via (3-aminopropyl)trimethoxysilane linker, the [Rh(cod)Cl]₂ complex on siliceous mesoporous molecular sieves differing in the pore size and architecture (MCM-41, MCM-48 and SBA-15). In comparison with [Rh(cod)Cl]₂ used as homogeneous catalyst, all hybrid catalysts exhibited comparable or even higher catalytic activity in the polymerization of phenylacetylene and 4-ethynyl-N-{4-[(trimethylsilyl)ethynyl]benzylidene}aniline. The initial polymerization rate increased with increasing accessibility of mesoporous surface of catalysts in the order: MCM-41 < MCM-48 < SBA-15. Molecular weights of the prepared polymers increased in reverse order suggesting suppression of the chain growth termination reactions by space limitations in the pores. No effect of catalyst support on the microstructure of formed polymers was found.

The aim of this work was to study the influence of copper content and particle morphology on the performance of Cu/FeO_x catalysts in the gas-phase conversion of CO₂ with hydrogen. All four investigated catalysts with a copper content between 0 and 5 wt% were found highly efficient, with CO₂ conversion reaching 36.8%, and their selectivity towards C₁ versus C₂-C₄, C₂-C₄=, and C₅₊ products was dependent on catalyst composition, morphology, and temperature. The observed range of products is different from those observed for catalysts with similar composition but synthesized using other precursors and chemistries, which yield different morphologies. The findings presented in this paper indicate potential new ways of tuning the morphology and composition of iron-oxide-based particles, ultimately yielding catalyst compositions and morphologies with variable catalytic performances.

The effect of the framework Al content and synthesis procedure on the number of framework Al atoms located on the surface of (Al)MCM-41 channels and the distribution of the Al atoms between single Al atoms and various Al-O-(SiO)_1,2-Al species was investigated. The total number of accessible framework Al atoms on the channel surface was obtained from the ion exchange capacity for Na⁺ ions and pyridine adsorption. The number of Al pairs on the surface and their distribution between different local arrangements of the channel surface was estimated using VIS spectroscopy of Co²⁺ ions. At low framework Al contents, Al atoms occupy only accessible T sites on the surface of the channel walls. In aluminium-rich (Al)MCM-41, a significant part of Al atoms is incorporated inside the channel walls and these Al atoms do not form cationic sites. Al atoms on the wall surface preferentially form Al-O-(SiO)_1,2-Al sequences, enabling siting of divalent cations. Different synthesis procedures resulted in differences in Al distribution. The channel surface of the (Al)MCM-41 is formed by two regular local structures containing two types of deformed six-membered rings with Al-O-(SiO)_1,2-Al sequences forming cationic sites.