Tailoring of phase composition and photoresponsive properties of Ti-containing nanocomposites from layered precursor

Titanium-containing nanocomposites have been synthesized by calcination of a Ni-Ti layered double hydroxide as precursor. The nanocomposites were characterized by powder X-ray diffraction (PXRD), high-resolution transmission electron microscopy (HRTEM), the Brunauer-Emmett-Teller (BET) method, and UV-vis diffuse reflection spectroscopy (DRS). The transformation of the metastable Ni2TiO4 spinel phase to the stable NiTiO3 ilmenite phase was observed during the thermal process. The phase transformation at a calcination temperature below and at 800 degrees C belongs to the intraparticle reaction, while a phase separation occurs at 900 degrees C. UV-vis DRS indicates that the nanocomposites are not only responsive but also activated in both the UV- and visible-light regions. Their UV-vis-induced photocatalytic activities were evaluated by the degradation of methylene blue. The results show that the Ti-containing nanocomposites exhibit good photocatalytic activity under UV-vis-light irradiation.