I. B. Bychko

Catalytic Activity of Multiwalled Carbon Nanotubes in Acetylene Hydrogenation

The hydrogenation of acetylene was investigated on multiwalled carbon nanotubes (MWCNTs) with an average diameter of 35u2005nm and prepared by chemical vapor deposition from ethylene. The MWCNT structure and surface‐oxygen‐containing functional groups were verified by transmission electron microscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy, Raman spectroscopy, and Boehm titration. Significant differences in the surface functionalities of the MWCNTs were found before and after catalysis, but the morphology of the MWCNTs did not change. During catalysis, the MWCNTs are characterized by a large number of defects and the surface is functionalized with hydroxy and carbonyl groups. The MWCNTs demonstrated high selectivity towards ethylene formation. The formation of methane was not recorded. Our study indicates that acetylene hydrogenation proceeds according to a Langmuir–Hinshelwood mechanism.

Dependence of Structure of Multilayer Graphene Oxide on Degree of Graphitization of Initial Graphite

It was shown that the structure of multilayer graphene oxide (GrO) synthesized by Tour method depends substantially on the degree of graphitization (g) and on the particle size of initial graphite. The obtained GrO was characterized by Raman and infrared spectroscopy, X-ray diffraction, and elemental analysis. The GrO contains carbonyl, carboxyl, and hydroxyl groups as well as C–O–C fragments. The dependence of the O/C molar ratio of GrO on the degree of graphitization of the parent graphite is nonmonotonic with a maximum at g ≈ 90%.

Catalytic Activity of N-Doped Reduced Graphene Oxide in the Hydrogenation of Ethylene and Acetylene

Catalytic activity was shown for N-doped reduced graphene oxide (N-RGO), subjected to prior thermal reduction in a hydrogen atmosphere, in the hydrogenation of ethylene and acetylene. Samples of N-RGO and activated N-RGO (N-RGO-H2) were characterized by SEM, TEM, IR spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). Our results indicate the catalytic activity of N-RGO-H2 may be attributed to the presence of nitrogen-containing fragments, which may reveal frustrated Lewis pairs properties.

Catalytic Cracking of Triglycerides on α-FeOOH Nanoparticles

Nanoparticles of α-FeOOH with diameter 9.0 ± 0.8 nm catalyze the cracking of vegetable oil triglycerides to give motor fuel components in the temperature range 300-450 °C. The greatest amount of normal alkanes and least amount of oxygen-containing compounds are found in the liquid product mixture at 400 °C. The major products are components of the gasoline and diesel fractions.

Size Effect in Ethylene Hydrogenation over Palladium Catalysts Supported on γ-Al2O3

Colloid deposition was used to prepare catalysts with controlled-size palladium nanoparticles supported on γ-Al2O3. The rate of ethylene hydrogenation was found to increase with increasing diameter of the palladium nanoparticles in the 4-6 nm range. The effective reaction activation energy was found to be independent of the size of the palladium nanoparticles. Thus, this nanodimensional effect may be a consequence of change in the ratio of the areas of the different crystallographic faces of palladium on the catalyst surface.

Nanosize Effect in Heterogeneous Catalytic Processes Over Copper, Iron, and Zirconium Oxides

A summary is given of the results of studies of the catalytic properties of nanophase systems derived from copper, iron, and zirconium oxides in the ethanol steam reforming, the oxidation of carbon monoxide, the preferential oxidation of CO in the presence of excess hydrogen, the oxidation of benzyl alcohol, and the cracking of triglycerides. A relationship was found between the catalytic activity of copper, iron, and zirconium oxides and the size of their nanoparticles. The reasons for the nanophase effect in these processes were elucidated for a number of systems.

Heterogeneous Catalytic Production of Nitrogen-Containing Macrotubes from Acetonitrile Using Iron Nanoparticles

The possibility of producing nitrogen-containing multiwalled carbon macrotubes with an average external diameter of 220 nm was demonstrated for the first time. The macrotubes are characterized by bamboo-like morphology and are formed on aggregated particles of iron.