A titanium dioxide powder co-doped with boron and zirconium was prepared by mechanical ball milling. Photocatalytic performance of the powder was evaluated by degradation of methylene blue (MB) solution under UV illumination. XRD patterns were refined by Rietveld analysis method to obtain accurate lattice parameters and position of the atoms in the crystal structure of TiO2. XRD analysis indicated that the B and/or Zr doped TiO2 powders composed of anatase and did not exhibit any additional phase. Rietveld analysis suggested that dopant B and Zr elements were successfully weaved into crystal structure and distorted the lattice of TiO2. The highest distortion was obtained by co-doping. SEM investigations confirmed that mechanical ball milling technique led to a decrease in particle size of TiO2 powder. XPS analysis revealed that dopant B and Zr atoms did not appear in any form of compound including Ti and O elements. Results of photocatalytic activity test suggested that boron and zirconium co-doped TiO2 particles exhibited a better visible light response and photocatalytic activity than that of mono element doped TiO2 (i.e. B-TiO2 and Zr-TiO2) and undoped TiO2 particles. A 20% improvement in photocatalytic activity of reference TiO2 powder (powder ball milled without dopant addition) was achieved by B and Zr co-doping. The enhanced photocatalytic activity is attributed to synergistic effects of B-Zr co-doping the lattice of TiO2 as well as particle size reduction.

Apatite was formed on the surface of titanium dioxide (TiO2) powders by a biomimetic process. The deposition was accomplished by immersing TiO2 powders in simulated body fluid (SBF) for 1, 3, 6, 12, and 24 h. SBF used throughout this study had calcium and phosphate ion concentrations 10 times greater than those of human blood plasma. Photocatalytic activity of the apatite-deposited TiO2 powders was investigated in terms of the decomposition of methylene blue solution under ultraviolet (UV) irradiation. It has been shown that apatite deposition enhanced the photocatalytic activity of TiO2. The best photocatalytic performance was acquired on the powders that are immersed in SBF for 3 h. The time required for the complete degradation of methylene blue decreased from 3.5 h to 2 h upon immersion of powders in SBF for 3 h. Photochemical durability of poly(methyl methacrylate) increased when it was mixed with apatite-deposited TiO2 powders.