A short solid-state synthesis leading to titanate compounds with porous structure and nanosheet morphology

A novel method was developed for the synthesis of titanate nanosheets with high surface area. A solid-state mixture of NaOH and TiO2 was reacted at 600 °C for several minutes. The aqueous dispersion of the resulting melt was aged at room temperature for periods up to 14 days. After hydrochloric acid treatment and washing procedures, the reaction product was characterized by X-ray diffraction, Raman spectroscopy, N2-sorption and small-angle X-ray scattering measurements. The titanate compound not subjected to the aging process was amorphous and possessed a microporous framework, while the aged samples displayed nanosheet morphology and high specific surface area (396–509 m2 g−1). It was revealed that the very short heat treatment is of crucial importance for the titania-titanate phase transformation, while the aging process is needed for the morphological evolution of the titanate samples. The effects of the aging time on the structure and the morphology are discussed.

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► A short solid-state synthesis leading to titanate nanosheet powders is presented.
► The aging process is needed for the morphological evolution of the as-prepared titanate.
► The acid treated titanate aged for 14 days displayed only nanosheet morphology.
► The obtained titanate nanosheet powders possess very high surface area (>500 m2 g−1).
► The titanate nanosheets are transformed to pure anatase upon calcination at 700 °C.