Jul 7, 2014
Exploring the photocatalytic properties of titania and graphene nanocomposites
A simple sol-gel method can be used to synthesize high-performance iron-doped titania (Fe-TiO2) on the surface of graphene sheets in methanol. Compared with similar samples prepared without graphene, the resulting nanocomposites show higher visible light absorption as well as higher surface areas. Presented in Nanotechnology, these results could have an application in addressing various environmental issues.
Physisorption and chemisorption of anatase titania on graphene and functionalized graphene substrates
The prepared nanomaterials are examined for the visible light degradation of 17β-estradiol (E2) – an endocrine disrupting hormone. Higher photocatalytic activity using the Fe-TiO2/graphene assemblies is observed. The graphene enhances the results through better dye adsorption, further extension of the photoresponsive range, and enhancement of the charge separation and transportation properties.
Density functional theory (DFT) is utilized to help explain the experimental results. This builds on a previous study from the team at the University of Western Ontario that examines the interaction energy between titania nanostructures and graphene (Ayissi et al. 2013). In this DFT study, the binding strength is examined between iron-doped anatase TiO2 nanostructures and their interaction with pure and functionalized graphene.
The adsorption study shows that a weight ratio of 6% Fe-TiO2 binds more strongly to graphene than the pure anatase titania nanostructures. A change in doping concentration of Fe:TiO2 titania does not show a clear effect on the adsorption but confirms a binding strength edge compared to pure anatase titania.
Additional theoretical calculations identify FeTi15O32 as the nanostructure giving an energy minimum, and therefore higher stability, when physisorbed on graphene and chemisorbed on functionalized graphene. Density of states calculations confirm a decreasing value of the bandgap of anatase titania with respect to an increasing Fe-doping concentration. These materials provide new possibilities in the investigation of TiO2-graphene composites and their practical application in mediating against environmental issues.
More information can be found in the journal Nanotechnology 25 305601.