Ion-Beam Synthesis of Structure-Oriented Iron Nanoparticles in Single-Crystalline Rutile TiO₂

Magnetic nanoparticles embedded into semiconductors have current perspectives for use in semiconducting spintronics. In this work, 40 keV Fe+ ions were implanted in high fluences of (0.5 ÷ 1.5) × 1017 ion/cm2 into an oxide semiconductor and single-crystalline TiO2 plates of rutile structure with (100) or (001) face orientations. Microstructure, elemental-phase composition, and magnetic properties of the Fe-ion-implanted TiO2 were studied by scanning and transmission electron microscopies (SEM and TEM), X-ray photoelectron (XPS) and Rutherford backscattering (RBS) spectroscopies, as well as vibrating-sample magnetometry (VSM). The high-fluence ion implantation results in the formation of magnetic nanoparticles of metallic iron beneath the irradiated surface of rutile. The induced ferromagnetism and observed two- or four-fold magnetic anisotropy are associated with the endotaxial growth of Fe nanoparticles oriented along the crystallographic axes of TiO2

Effect of Mono-, Di-, and Triethylene Glycol on the Activity of Phosphate-Doped NiMo/Al2O3 Hydrotreating Catalysts

The effect of glycols on the catalytic properties of phosphate-doped NiMo/Al2O3 catalysts in the hydrotreating of straight-run gas oil (SRGO) was studied. The NiMo(P)/Al2O3 catalysts were prepared using ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) as additives. The organic agent was introduced into the aqueous impregnation solution obtained by the dissolving of MoO3 in H3PO4 solution, followed by Ni(OH)2 addition. The Raman and UV–Vis studies show that the impregnation solution contains diphosphopentamolybdate HxP2Mo5O23(6−x)− and Ni(H2O)62+, and that these ions are not affected by the presence of glycols. When the impregnation solution comes in contact with the γ-Al2O3 surface, HxP2Mo5O23(6−x)− is decomposed completely. The catalysts were characterized by Raman spectroscopy, low-temperature N2 adsorption, X-ray photoelectron spectroscopy, and transmission electron microscopy. It is shown that the sulfide catalysts prepared with glycols display higher activity in the hydrotreating of straight-run gas oil than the NiMoP/Al2O3 catalyst prepared without the additive. The hydrodesulfurization and hydrodenitrogenation activities depend on the glycol type and are decreased in the following order: NiMoP-DEG/Al2O3 > NiMoP-EG/Al2O3 > NiMoP-TEG/Al2O3 > NiMoP/Al2O3. The higher activity of NiMoP-DEG/Al2O3 can be explained with the higher dispersion of molybdenum on the surface of the catalyst in the sulfide state