Reduced graphene oxide-titanate hybrids: Morphologic evolution by alkali-solvothermal treatment and applications in water purification

The reduced graphene oxide-titanate (RGO-Ti) hybrids were fabricated by incorporating spherical TiO2 nanoparticles with graphene oxide (GO) layers in aqueous NaOH solution following by the solvothermal treatment. The morphologic evolution of RGO-Ti hybrid by varying alkali-solvothermal temperatures has been first investigated. The titanate nanosheets peeled off, folded and scrolled into tubular structure; and eventually, cracked and destroyed to be ribbon-like shape. The chemical interaction and attachment of low-dimensional titanate onto RGO layers and the reverse order were elucidated by X-ray photoelectron spectra. The hybrids in sheet and tubular titanate structures possessed larger surface areas (>350 m2/g) and higher pore volumes (>1 cm3/g) than the other. The presence of RGO sheets as a two-dimensional (2D) platform for the deposition of titanate significantly promoted much better adsorptivity of dye contaminants compared to pure materials.

Highlights► Reduced graphene oxide-titanate hybrids are synthesized by solvothermal process. ► Reduced graphene oxide acts as a two dimensional platform for titanate growth. ► Titanate sheets transform into tubes or ribbons at high solvothermal temperatures. ► The hybrids possess large surface areas and high pore volumes. ► The hybrid materials exhibit excellent adsorptivity of dye contaminants.