Surface-modified anatase nanocrystalline building blocks for constructing catalytically highly active nanoporous titania materials

Anatase nanocrystals with controlled size, shape and modified surface have been prepared and applied as nanocrystalline building blocks for surfactant-directed spontaneous assembly in aqueous solution. The nanocrystals were synthesized in a mixture of titanium tetrachloride and benzyl alcohol with the addition of pyridine as a modifying ligand. It was found that pyridine retarded the growth of anatase nanocrystals, preferentially along the c axis, and its addition resulted in nanocrystals with higher percentage of the high-energy {0 0 1} facets. Moreover, the nanocrystals was modified with pyridine chemisorbed at surface acid sites that were most likely to be associated to the five-coordinated titanium atoms. The pyridine-modified anatase nanocrystals interacted with sodium dodecyl sulfate in acidic aqueous solution, causing a spontaneous surfactant-directed assembly. After calcination, the surfactant-free nanoporous material exhibited high anatase crystallinity, high surface area, uniform mesoporosity and preferred surface properties. Owing to the textural and surface properties, the assembled material exhibited excellent catalytic activities in the photodegradation of methylene blue and in the epoxidation of cyclohexene with hydrogen peroxide as compared to reference titania samples.

Figure optionsDownload as PowerPoint slideHighlights▸ Anatase nanocrystals with modified surface have been prepared. ▸ Pyridine retards anatase growth and modify the surface. ▸ The nanocrystals spontaneously assemble with anionic surfactant in water. ▸ The assembled material has high surface area and uniform mesoporosity. ▸ It exhibits excellent photocatalytic activity and epoxidation activity.