Octahedral Shaped PbTiO₃-TiO₂ Nanocomposites for High-Efficiency Photocatalytic Hydrogen Production

In this work, octahedral shaped PbTiO₃-TiO₂ nanocomposites have been synthesized by a facile hydrothermal method, where perovskite ferroelectric PbTiO₃ nanooctahedra were employed as substrate. The microstructures of the composites were investigated systemically by using XRD, SEM, TEM and UV-Vis spectroscopy. It was revealed that anantase TiO₂ nanocrystals with a size of about 5 nm are dispersed on the surface of the {111} facets of the nanooctahedron crystals. Photocatalytic hydrogen production of the nanocomposites has been evaluated in a methanol alcohol-water solution under UV light enhanced irradiation. The H₂ evolution rate of the nanocomposites increased with an increased loading of TiO₂ on the nanooctahedra. The highest H₂ evolution rate was 630.51 μmol/h with the highest concentration of TiO₂ prepared with 2 mL tetrabutyl titanate, which was about 36 times higher than that of the octahedron substrate. The enhanced photocatalytic reactivity of the nanocomposites is possibly ascribed to the UV light absorption of the nanooctahedral substrates, efficient separation of photo-generated carriers via the interface and the reaction on the surface of the TiO₂ nanocrystals.