Doped TiO2 photocatalysts have been prepared by a coprecipitation method. Uniformly doped nanocrystalline TiO2 of 10-20 nm sizes was synthesized by calcinating the coprecipitated gels at 400-650 degreesC. Photocatalytic characterization along with the microstructural investigation for each catalyst provides better understanding of the photocatalytic behavior. It was found that the photodegradation of methylene blue (MB) was a complex function of the doping type and its concentration and the microstructural characteristics of the catalysts. Antimony doing significantly improved photocatalytic performance as compared to the undoped TiO2. Post-treatment of the as-precipitated wet doped Ti gels in an organic solvent also increased the surface area, forming approximately 8 nm size doped TiO2 with surface area similar to 149 m(2)/g. Superior catalytic activity was observed in the Sb-doped TiO2 samples at a doping concentration ranging from 1 to 5 at%. Using the 5 at% Sb-doped TiO2 catalyst treated in butanol, 100 ppm of MB could be decomposed completely within 1 h, which was better than the commercial Degussa P-25.