6 research outputs found
Interaction between the silyl and silylen centres in the deposits prepared by pulsed laser ablation of silicon monoxide and ammonia, methylamine and dimethylamine
Thermal reactions in mixtures of micron-sized silicon monoxide and titanium monoxide: redox paths overcoming passivation shells
SmÄ›snĂ© oxidy a kompozity oxidu TiO2/SiO2 byly intenzivnÄ› studovány, zatĂmco kekich protÄ›jšky oxidu titanatĂ©ho (TiO) a oxidu kĹ™emnatĂ©ho (SiO) stále zĹŻstávajĂ neprozkoumány. Tato studie odhaluje strukturálnĂ zmÄ›ny ve zahřátĂ˝ch smÄ›sĂch SiO-TiO. ZmÄ›ny sloĹľenĂ ve smĂsenĂ˝ch mikro-částicĂch TiO a SiO zahĹ™ĂvanĂ˝ch pĹ™i 1000 ° C byly zkoumány pomocĂ FTIR, UV-Vis a Ramanovy spektroskopie, rentgenovĂ© difrakce a elektronovĂ© mikroskopie (SEM a TEM). Ukazuje se, Ĺľe docházĂ k Ăşbytku krystalickĂ©ho TiO a tvorbÄ› suboxidĹŻ titanu (Ti2.5O3, Ti2O3), rutilu, elementárnĂho kĹ™emĂku, silicidu titanu Ti5Si3 a amorfnĂch binárnĂch SiOx, TiOx a ternárnĂch nanostruktur SixTiyOz. Tvorba tohoto Si/Ti/O kompozitu je vysvÄ›tlena disproprciacĂ SiO, redukcĂ TiO kĹ™emĂkem, pĹ™enosem kyslĂku (redoxnĂ reakce) mezi TiOx a SiOx a kombinacĂ Ti a Si k zĂskánĂ silicidu titanu. VytvoĹ™enĂ˝ Si/Ti/O kompozit absorbuje viditelnĂ© svÄ›tlo a jeho fotokatalytická aktivita ve sluneÄŤnĂm zářenĂ byla testována na odbarvovánĂ methylenovĂ© modĹ™i (bBlue) a porovnávána s práškem nezahřátĂ©ho SiO, TiO a Ti5Si3.Silica–titania mixed oxides and composites have been extensively studied, whereas the titanium monoxide (TiO)–silicon monoxide (SiO) counterparts still remain to be explored. Here, we report on structural changes in heated SiO–TiO mixtures. The changes in composition in intimately mixed ÎĽm-sized particles of TiO and SiO heated at 1000 °C were examined by FTIR, UV–Vis and Raman spectroscopy, X-ray diffraction and electron (SEM and TEM) microscopy. They are shown to involve depletion of crystalline TiO and formation of titanium suboxides (Ti2.5O3, Ti2O3), rutile, elemental silicon, titanium silicide Ti5Si3 and amorphous binary SiOx, TiOx and ternary SixTiyOz nano-structures. These constituents of the developed Si/Ti/O composite are explained by SiO disproportionation, reduction of TiO by silicon, oxygen transfer (redox) reactions between TiOx and SiOx species and the combination of Ti and Si to obtain titanium silicide. The produced Si/Ti/O composite absorbs visible light and its solar-light photocatalytic activity in decolorization of methylene bBlue is compared to that of the unheated SiO, TiO and Ti5Si3 powders