Solvent effect on the structure and photocatalytic behavior of TiO2-RGO nanocomposites

• Published in: Journal of materials research 2019-12, Vol.34 (23), p.3918-3930
• Main Authors: Gonçalves, Bruno S., Silva, Lucas M. C., de Souza, Tarcizo C. C., de Castro, Vinícius G., Silva, Glaura G., Silva, Bruno C., Krambrock, Klaus, Soares, Renata B., Lins, Vanessa F. C., Houmard, Manuel, Nunes, Eduardo H. M.
• Format: Article
• Language: English
• Subjects: Adsorption; Alcohol; Applied and Technical Physics; Biomaterials; Carbon; Catalytic activity; Crystallites; Current carriers; Graphene; Influence; Inorganic Chemistry; Materials Engineering; Materials research; Materials Science; Nanocomposites; Nanoparticles; Nanotechnology; Particle size; Photocatalysis; Sol-gel processes; Solvent effect; Solvents; Titanium; Titanium dioxide; Ultraviolet radiation
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/jmr.2019.342

There is no agreement regarding which solvent is more suitable to obtain sol–gel–derived titania (TiO 2 ) samples with an enhanced photocatalytic behavior. Furthermore, the solvent effect on the preparation of TiO 2 -RGO (reduced graphene oxide) nanocomposites has not been published yet and could be an attractive experimental strategy to modulate structure and properties. On the basis of these observations, TiO 2 -RGO nanocomposites were fabricated in this study. It was evaluated for the influence of using either isopropyl (IsoprOH) or ethyl (EtOH) alcohol on the textural and photocatalytic properties of the prepared materials. The use of IsoprOH led to samples with smaller crystallite size, narrower apparent band gap, smaller isoelectric point, larger adsorption capacity, and higher photocatalytic activity. In addition, the incorporation of RGO into TiO 2 greatly improved the adsorption capacity and photocatalytic activity of the latter. However, the optimal loading of RGO to prepare composites with enhanced photocatalytic activities was 1 wt%. This finding can be related to the stacking of RGO sheets when concentrations above 1 wt% are used, which could prevent UV light to reach the TiO 2 particles and also decrease the photocatalytic capacity of the composites. Moreover, materials with RGO concentration above 1 wt% could exhibit a highly negatively charged surface, which may decrease the separation of the generated electron–hole pairs and lead to faster recombination rates of charge carriers.