Preparation of anatase TiO₂ fibers with cheap Ti(SO₄)₂ as titania precursor

Fibers Na₂Ti₃O₇ were prepared using cheap Na(SO₄)₂ as titania precursor, and two methods were developed to produce anatase TiO₂ fibers. The first method is hydrothermal treatment of Na₂Ti₃O₇ fibers in 0.05 mol/L HNO₃ solution, and the second method is to ion-exchange the Na₂Ti₃O₇ fibers with 0.1 mol/L HCl, followed by calcining at 500-800°C. The microstructure and properties of samples were characterized by the scanning electron microscope, transmission electron microscope, energy dispersive X-ray analysis, X-ray diffraction, and N₂ adsorption/desorption. The results indicate that Na₂Ti₃O₇ fibers are of a solid structure and the length/width ratio is over 100. Anatase TiO₂ fibers prepared using the first method had lengths of 5-15 μm and a width of ca 80 nm, with some TiO₂ nanoparticles with a size of ca 25 nm covered on the fibers. The titania fibers prepared by the second method experience the structural changes from H₂TiO₃-TiO₂(B)-anatase TiO₂ fibers when Na₂Ti₃O₇ fibers are ion-exchanged and calcined. The final anatase TiO₂ fibers have integrity and have lengths of 5-10 μm and a width of ca 200 nm.