Carbon nanosheet-titania nanocrystal composites from reassembling of exfoliated graphene oxide layers with colloidal titania nanoparticles

Nanoporous composites of carbon nanosheets (CNS) and titania nanoparticles (NPs) were synthesized by reassembling of delaminated graphite oxide (GO) layers with titania clear sol (TCS), and their structural and porous properties were examined by various physico-chemical methods such as XRD, TG/DTA, FT-IR, Raman, FE-SEM/TEM, and low temperature N-2 adsorption. It was found that the facile approach, which utilizes the electrostatic attraction between the negatively charged GO layers and the positively charged TCS particles, leads to a well composed CNS and ultrafine TiO2 NPs material whose titania amount reaches up to 71 wt%. The titania phase in these composite materials is mainly anatase, which is resistible against high temperature calcination, but also contains a little amount of rutile and brookite depending on synthesis condition. The porosity of the composite is improved and partially affected by the size distributions of TiO2 NPs. The unique structure, better porosity, and compatible surface affinity of these composites bring about an adsorption concentration-promoted photocatalytic effects toward organic dyes by successfully combining both properties of CNS and titania NPs. (C) 2012 Elsevier Inc. All rights reserved.