Photocatalytic removal of phenol and methylene-blue in aqueous media using TiO2@LDH clay nanocomposites

• TiO2@LDH nanocomposites were obtained by the deposition of anatase seeds on LDH-type clay materials.
• Zn2+, Cu2+, Al3+, Fe3+ or Ti4+ cations were inserted within the LDH clay lattice.
• Photoresponsive properties were observed in both UV and Vis range of the solar spectrum.
• The TiO2@LDH nanocomposites are efficient for photodegradation reactions.

Herein, we report the formation of a series of nanocomposites composed of LDH structures and TiO2 with anatase crystal phase. The structure of the LDH clay was modulated by the insertion of different di-, tri- or tetravalent cations, such as Zn2+, Cu2+, Al3+, Fe3+ or Ti4+, within the brucite-like sheets. Afterwards, the anatase seeds were deposited onto the LDH clays, obtaining new nanocomposite systems with tailored photocatalytic activity. In this way, the photoresponsive properties of the final nanocomposites were shifted from the UV to the visible range of the solar spectrum. The obtained nanocomposites were tested for the degradation of different organic pollutants, like phenol and methylene blue, under UV and visible light in aqueous media with different pH. The kinetic study showed that the TiO2@LDH nanocomposites are efficient for the phenol (and its intermediary species catechol and hydroquinone) and methylene blue photocatalytic degradation under both UV and Vis light illumination.

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