Artem B. Ayupov

Platinum nanoparticle size effect on specific catalytic activity in n-alkane deep oxidation: Dependence on the chain length of the paraffin

The specific activity of 0.8% Pt/Al2O3 catalysts in the deep oxidation of C1–C6n-alkanes increases with an increase in the Pt particle size from 1 to 3–4 nm. Further coarsening of the particles insignificantly changes the specific activity. The size effect was studied for a series of catalysts containing platinum nanoparticles 1 to 11 nm in diameter. The specific catalytic activity variation range depends on the size of the reacting hydrocarbon molecules. As the platinum particle size increases, the specific catalytic activity increases 3–4 times for the oxidation of CH4 and C2H6 and by a factor of 20–30 for the oxidation of n-C4H10 and n-C6H14.

Direct contact free real-time acquisition of temperature profiles in adsorbent bed during vacuum swing adsorption

Real-time temperature co-axial profiles in a bed of mesoporous alumosilicate were recorded by means of FPA-based infrared thermography during air drying vacuum swing adsorption cycles. The good correlation between experimentally measured temperature profiles and profiles simulated on the basis of linear driving force model of mass and heat transfer in nonadiabatic regime is observed.

Adsorption and Textural Properties of LSX Zeolite at the Initial Stages of Destruction

Alteration of adsorption properties and porous structure (texture) of the KNaLSX zeolite at the initial stages of its destruction during ion-exchange modification in solutions of NH4Cl and thermal shock under vacuum degassing has been studied. Transmission electron microscopy, X-ray diffraction, low-temperature nitrogen adsorption and adsorption of CO2 and CH4 at 273 K were applied for characterization of the obtained materials. Conversion of the predominantly microporous material to the material with threemode pore-size distribution is shown. Significant fraction of the faujasite phase and corresponding micropores are preserved in the material. This is accompanied with formation of pores of two types: quasi-spherical mesopores with the characteristic size of 5 nm and the meso-macropores with typical size exceeding 40 nm. Basing on the obtained results, a mechanism of textural changes in the LSX zeolite treated under applied conditions is proposed.