Titanium oxide nanoparticles, preparation

Matsuno R, Otsuka H, Takahara A (2006) Polystyrene-grafted titanium oxide nanoparticles prepared through surface-initiated nitroxide-mediated radical polymerization and their application to polymer hybrid thin films. Soft Matter 2(5) 415... 

Yun YH, Youn YN, Yoon SD, Lee JU (2012) Preparation and physical properties of starch-based nanocomposite films with the addition of titanium oxide nanoparticles. J Ceram Process Res... 

Immobilizing DENs within a sol-gel matrix is another potential method for preparing new supported catalysts. PAMAM and PPI dendrimers can be added to sol-gel preparations of silicas " and zinc arsenates to template mesopores. In one early report, the dendrimer bound Cu + ions were added to sol-gel silica and calcined to yield supported copper oxide nanoparticles. Sol-gel chemistry can also be used to prepare titania supported Pd, Au, and Pd-Au nanoparticle catalysts. Aqueous solutions of Pd and Au DENs were added to titanium isopropoxide to coprecipitate the DENs with Ti02. Activation at 500°C resulted in particles approximately 4 nm in diameter. In this preparation, the PAMAM dendrimers served two roles, templating both nanoparticles and the pores of the titania support. 

Hydrofluoric acid — (HF) A solution of hydrogen fluoride in water. The pure hydrogen fluoride is characterized by Mw of 20.0063 gmol-1 m.p. -83.55 °C (1 atm) b.p. 19.5 °C (latm). When concentrated, this colorless fuming liquid is extremely corrosive and can dissolve almost all inorganic oxides such as silicate compounds or oxides of metals like stainless steel, aluminum, and uranium however, it can be stored in casted iron bottles because a corrosion-resistant iron fluoride layer protects the metal. It is used for several purposes such as the preparation of titanium oxide nano tube arrays [i], silicon nanoparticles [ii] and electrochemical etching of silicon [iii], electrochemical deposition of lithium [iv], etc. 

The micro-emulsion medium was heated to 120-200 °C in a stainless steel autoclave. Micro-emulsions acidified with HNO3 produced monodispersed anatase nanoparticles while those acidified with HCl produced rutile nanorods. Titanium dioxide (Ti02) nanoparticles prepared this way have been shown to be active toward the photocatalytic oxidation of phenol [172]. 

Incorporation of titanium oxide species within the framework of mesoporous silicas has been shown to produce highly efficient photocatalytic materials. Extremely careful preparation conditions [84] leads to highly structured materials comprising anatase nanoparticles of dimension between 5 and 10 run. The channeled structure, together with the hydrophobic/hydrophilic character, are also key features controUing their enhanced photoreactivity. The photocatalytic activity of such mesoporous catalysts has been studied for the degradation of phenol in aqueous solutions [85]. It was observed that for structured mesoporous materials with low Ti content, the turnover frequency was four times greater than that for standard P25. 

Phenol is one of the toxic materials in municipal and wastewater. Titanium dioxide nanoparticles of both anatase and rutile forms were synthesized by hydrothermal treatment of microemulsions and used in the wet oxidation of phenol [363]. The advantage of this method of preparation is that the size of particles can be affected by the ratio of surfactant to water. Size of water droplets in the reverse microemulsions is approximately the same as that of formed particles. The main reactions in phenol degradation are [363] ... 

TiN nanoparticles also have been prepared by various methods such as CVD (52), cathodic arc deposition (53), and electrochemical reduction of titanium oxide (54). Thus, TiN nanoparticles were deposited on epo resin by electrochemical reduction with high cathodic potential of-1.5 V at room temperature (54). 

The preparation of hybrid materials based on BC comprises a limited number of inorganic nanoparticles (NPs) such as a few metals (silver [211-231], selenium [214, 232-234], gold [223, 224, 235], nickel [236, 237], platinum [210] and palladium/cop-per [238]), metal oxides (silica [239-247], titanium oxide [242, 248-255], iron oxides [209, 221, 256-267], zinc oxide [268-270], vanadium oxide [254]), calcium phosphate... 

Boron nitride nanocages with silver nanoparticles encapsulated in them have been synthesized by Oku et al." Reaction of urea and boric acid in the presence of silver nitrate produced BN matrices at 700°C. The ingredients were previously dissolved in deionized water and dried consequently to produce a homogenous mixture and annealed separately at 300°C and 700°C. The presence of silver nanoparticles and sometimes silver oxide nanoparticles were detected under TEM (Figure 20.15a) and x-ray diffraction studies. A similar methodology has been developed by Xing et al. in their preparation of zinc oxide- and titanium oxide-encapsulated BN nanocages." ... 

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