Background: The potential of applying TiO2-based materials has been ascertained in both
wastewater and polluted air. Boron is proven to be an effective dopant to promote the activity of
TiO2 in our previous work. The density of hollow material is little larger than water so that the hollow
photocatalyst can suspend in wastewater under stirring or aeration.
Methods: The graphical spheres were prepared from glucose using hydrothermal method. The hollow
spherical x%B-TiO2 was synthesized through a sol-gel route, using tetrabutyl titanate and tributyl
borate in the precursor. The materials were characterized by X-ray diffraction, scanning electron
microscope, infrared spectrum, X-ray photoelectron spectroscopy, and N2 adsorption-desorption
techniques. Photocatalytic degradation of RBR X-3B dye was studied to show the activity of the
Results: Anatase TiO2 phase forms in all the x%B-TiO2 samples despite the difference in boron content.
An absolute Ti4+ oxidation state exists in the x%B-TiO2, which is hardly affected by the doped
boron. XPS analysis proves the formation of B-Ti-O structure in anatase TiO2 lattice. BET surface
area increases with rising boron doping content in the hollow spherical x%B-TiO2 samples. Photocatalytic
activity of TiO2 is enhanced after doping boron. The photocatalytic efficiency on RBR X-
3B degradation reaches the maximum value when n(B)/n(Ti) is 8%. After five photocatalytic cycles,
decoloration efficiency on 8%B-TiO2 is as much as 80% of the initial value.
Conclusion: A continuous expansion of TiO2 crystal happens with increasing boron content. The
Ti4+ oxidation state of titanium in the hollow spherical material is not changed after doping boron.
BET surface area of the hollow spherical x%B-TiO2 increases with rising boron doping content. The
hollow spherical 8%B-TiO2 has satisfactory performs for recycling and lifetime.