Facile method to obtain anatase and anatase-brookite nanoparticles (TiO2) with MWCNT towards reducing the bandgap

• Published in: Diamond and related materials Vol. 109; p. 108015
• Main Authors: Rosado, Gabriel, Valenzuela-Muñiz, Ana María, Miki-Yoshida, Mario, Gómez, Ysmael Verde
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-11-2020; Elsevier BV
• Subjects: Amorphous materials; Anatase; Anatase-brookite; Band gap reduction; Brookite; Carbon; Carbon nanotubes; Chemical bonds; Composite materials; Energy gap; Heat treatment; Low temperature; Low temperature method; Multi wall carbon nanotubes; Nanoparticles; Particle size distribution; Phases; Sol-gel processes; Surface area; Synthesis; Thermogravimetric analysis; TiO2 nanoparticles; Titanium dioxide; Carbon nanotubes; Anatase-brookite; Low temperature method; TiO2 nanoparticles; Band gap reduction
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2020.108015

Synthesis of TiO2 nanoparticles in anatase, and anatase-brookite phase mixture, deposited over multilwalled carbon nanotubes (MWCNT) is reported. The materials were obtained from an amorphous titania and MWCNT initial composite, using the sol-gel method at low temperature. To achieve the different crystalline phases, the initial composites were treated at different conditions: i) for the anatase phase, a thermal treatment at 400 °C was carried out, and ii) for the anatase-brookite mixture, the composite was placed in a reflux system at 80 °C during 5 h. The nominal weight percentage of MWCNT added to composites was 5%. The influence of MWCTN on the physical-chemical parameters of TiO2 was studied using diverse characterization techniques such as thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, Raman and UV spectroscopies, and surface area analysis. Results indicate that the TiO2 crystal sizes of the different phases was not affected for the addition of MWCNT. Although, there was an effect on the surface area, vibrations of molecular bonds and on the band gap energy, indicating an interaction between the TiO2 nanoparticles and the carbonaceous support.
The novelty of the presented research work is the finding of a facile methodology using mild conditions (400 °C) to obtain TiO2 nanoparticles in anatase and anatase-brookite phases in a composite material with carbon nanotubes. The effect of the synthesis conditions as well as the addition of multiwalled carbon nanotubes to TiO2 particles was studied. The most significant achievement was to increase the surface area of the materials while reducing the bandgap. In addition it was possible to obtain small particle size and a well distribution of phases.
[Display omitted]
•Facile obtainment of TiO2 nanoparticles (anatase, anatase-brookite) on MWCNT•Amorphous TiO2 and MWCNT composites were treated at mild conditions (below 400 °C).•The interaction of TiO2 nanoparticles and MWCNT was analyzed.•Composites exhibited features such as surface area increment and band gap reduction.•Materials are suitable to be used in photo and photoelectrocatalytic processes.