Stabilization of Titanium Dioxide Nanoparticles at the Surface of Carbon Nanomaterials Promoted by Microwave Heating

Abstract

TiO2 is frequently combined with carbon materials, such as reduced graphene oxide (RGO), to produce composites with improved properties, for example for photocatalytic applications. It is shown that heating conditions significantly affect the interface and photocatalytic properties of TiO2 @C, and that microwave irradiation can be advantageous for the synthesis of carbon-based materials. Composites of TiO2 with RGO or amorphous carbon were prepared from reaction of titanium isopropoxide with benzyl alcohol. During the synthesis of the TiO2 nanoparticles, the carbon is involved in reactions that lead to the covalent attachment of the oxide, the extent of which depends on the carbon characteristics, heating rate, and mechanism. TiO2 is more efficiently stabilized at the surface of RGO than amorphous carbon. Rapid heating of the reaction mixture results in a stronger coupling between the nanoparticles and carbon, more uniform coatings, and smaller particles with narrower size distributions. The more efficient attachment of the oxide leads to better photocatalytic performance.

Synthesis, characterization and enhanced photocatalytic CO2 reduction activity of graphene supported TiO2 nanocrystals with coexposed {001} and {101} facets

“…This is in line with the results of FTIR that GO was partially reduced to graphene through the solvothermal process. The reduction of GO during the solvothermal synthesis of TiO 2 /graphene composites has been reported before, 26,31 which can be attributed to the reduction of GO by solvent 32 and/or the reaction between the Ti-containing intermediate and the graphene surface, leading to the covalent attachment of TiO 2 . 31 The formation of C-O-Ti bonds may involve the reaction of TiO 2 with oxygen-containing groups on the surface of graphene, such as COOH and CQO groups.…”

“…The reduction of GO during the solvothermal synthesis of TiO 2 /graphene composites has been reported before, 26,31 which can be attributed to the reduction of GO by solvent 32 and/or the reaction between the Ti-containing intermediate and the graphene surface, leading to the covalent attachment of TiO 2 . 31 The formation of C-O-Ti bonds may involve the reaction of TiO 2 with oxygen-containing groups on the surface of graphene, such as COOH and CQO groups. 31,33 The reaction of TiO 2 intermediates with these groups can account for the low contents of oxygen-containing groups found in the G/TiO 2 -001/101 samples.…”

Mechanistic Aspects in the Formation, Growth and Surface Functionalization of Metal Oxide Nanoparticles in Organic Solvents

“…Besides the ether elimination byproducts spontaneous water release due to catalytic condensation of benzyl alcohol to dibenzyl ether at the Ti center led to an increase of pressure in the reaction system causing instant nucleation and fast growth of the crystalline anatase nanoparticles . According to 1 H NMR data, an analogous ether elimination reaction was also found for the formation of anatase TiO 2 nanoparticles prepared from the reaction of titanium isopropoxide with benzyl alcohol on the surface of carbon nanomaterials using microwave heating . The solvothermal reaction between titanium(IV) tert ‐butoxide and benzyl alcohol led to the elimination of di‐ tert ‐butyl ether and benzyl ether …”

“…[159] According to 1 HNMR data, an analogous ether elimination reaction was also found for the formation of anatase TiO 2 nanoparticles prepared from the reactiono ft itaniumi sopropoxide with benzyl alcohol on the surface of carbon nanomaterials using microwave heating. [160] The solvothermalr eaction between titanium(IV) tert-butoxide and benzyla lcoholl ed to the elimination of di-tert-butyl ether and benzyl ether. [157] An interesting observation was made during the synthesis of tungsten oxide nanowires from tungsteni sopropoxide in benzyla lcohol.…”

Electro-spun graphene-enriched carbon fibres with high nitrogen-contents for electrochemical water desalination

“…Finally, after filtering and washing with 2 M HCl solution (300 mL), the suspension was repeatedly washed with water and dried. Further details can be found elsewhere [25]. The obtainment of GO was ascertained by carrying out micro-Raman spectroscopy (MRS) and x-ray diffraction (XRD) analyses (Fig.…”