Photoelectrochemical Performance of Nb-doped TiO2 Nanoparticles Fabricated by Hydrothermal Treatment of Titanate Nanotubes in Niobium Oxalate Aqueous Solution

Nb-doped TiO2 nanoparticles were prepared by hydrothermal treatment of titanate nanotubes in niobium oxalate aqueous solution. The effect of Nb doping and rutile content on the photoelectrochemical performance based on TiO2 powder electrodes was investigated. The results show that Nb-doped TiO2 with a small amount of rutile exhibits the enhanced photoelectric conversion efficiency for dye-sensitized solar cell. The highest photoelectric conversion efficiency of 8.53% is obtained for 1% Nb-TiO2 containing a small amount of rutile. When a small amount of rutile contained in 2% Nb-TiO2, a higher photoelectric conversion efficiency of 8.77% is achieved.