Abstract:  Using tetrabutyl-titanate and sodium dihydrogen phosphate as raw materials, TiO₂ and P⁵⁺-doped TiO₂ semiconductors were prepared by the sol-gel method. Their pore distribution, crystal structure, surface compositions, and photoabsorption properties were investigated by N₂ adsorption-desorption, X-ray diffraction, Fourier transform infrared spectroscopy, FT-Raman, transmission electron microscopy and UV-Vis diffuse reflectance spectrum. The results show that P⁵⁺-doped TiO₂ exists in nano-particles of anatase phase with mesoporous structure. P⁵⁺-doped TiO₂ samples exhibit much smaller crystallite size and much higher specific surface area than pure TiO₂. P-doped TiO₂ samples show an extension of light absorption into the visible region, which mainly originates from the doping process with the formation of new energy level of P⁵⁺ between conductor band and valence band of TiO₂ to reduce the energy gap and the electron-hole recombination rate. The P⁵⁺-doped TiO₂ samples display improved photocatalytic activity for H₂ production from glycerol solution, and 5% P⁵⁺-doped TiO₂ shows a maximum H₂ production rate of 1838 μmol/(g·h) under UV irradiation and 209 μmol/(g·h) under simulated-solar irradiation, respectively, which is related to the decrease of crystal particles, increase of specific surface area, and the reduce of the energy gap and the electron-hole recombination rate.

Key words: phosphorus, doping, titanium dioxide, nano-particle, photocatalysis, glycerol solution, hydrogen production