Synthesis and characterization of porous TiO₂ with wormhole-like framework structure

A fast and reliable synthetic route for preparing contaminant-free porous TiO₂ with a wormhole-like framework and close packed macropores is demonstrated based on a sol-gel process involving acid hydrolysis of an alkoxide in the presence of a cationic surfactant. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements have been used to characterize the porous structure and the crystallinity. The XRD patterns, TEM and scanning electron microscopy (SEM) images confirm that these materials have disordered wormhole-like topology with close-packed nearly hexagonal macropores. The mesopore diameters and surface area of titanium dioxide, evaluated from the N₂-sorption isotherms, indicate average pore diameters of about 7 and 6 nm and surface areas of about 100 and 335 m²/g, for as-prepared and calcined samples at 400°C.