TiO2/graphene and TiO2/graphene oxide nanocomposites for photocatalytic applications: A computer modeling and experimental study

Abstract

Supplementary data related to this article can be found at http://dx. doi.org/10.1016/j.compositesb.2018.03.015. ; This work reports a computational study, focused on graphene (G) and graphene oxide (GO) interfaces with titanium dioxide (TiO2), and an experimental assay on the photocatalytic activity of TiO2/G and TiO2/GO nanocomposites in the degradation of two different pollutants: methylene blue and ciprofloxacin. Both carbon nanostructures were compared due to their different chemical structure: GO is a G derivative with oxygen functional groups which should promote a closer chemical interaction with TiO2 nanoparticles. Computational models of the fundamental properties of the composites indicated potentially improved photocatalytic activity compared to TiO2, namely lower band gaps and charge carrier segregation at the interfaces. These fundamental properties match qualitatively experimental results on methylene blue, which was more effectively degraded by TiO2/G and TiO2/GO nanocomposites than by pure TiO2 under UV light. In contrast, the same nanocomposites were found to be less efficient to degrade ciprofloxacin than pure TiO2 under visible and UV light. Therefore, this work showcases the relevance of an efficient matching between the catalyst and the molecular properties and structure of the pollutant. ; This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Project PESTC/FIS/UI607/2014 and PEST-C/QUI/UIO686/2014 and the CICECO Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT ref. UID/CTM/50011/2013). Access to computing facilities provided by the Project "Search-ON2: Revitalization of HPC infrastructure of UMinho" (NORTE-07-0162-FEDER-000086) is also acknowledged. P. M. Martins and Luciana Pereira thanks the FCT for grants SFRH/BD/98616/2013 and SFRH/BPD/110235/2015, respectively. MMF for a program Ciência 2008 fellowship. The authors thank financial support from the Basque Government Industry Department under the ELKARTEK ...