A novel approach was developed for the synthesis of high-dispersed anatase nano-TiO2 by a hydrothermal process without solvent at 200 degrees C in 1 h. It was characterized using XRD, TEM, BET and elemental analysis. Nanoparticle-TiO2 was used as a photocatalyst by considering complete degradation of Rhodamine B (RB) dye. The photocatalytic reaction parameters such as photocatalyst amount, irradiation time and dye concentration were optimized and it was found that 0.125 wt% catalyst in 30 mg/ L of RB aqueous solution is adequate for full degradation of RB in 50 min with 770 W/ m(2) irradiation power. Photocatalytic activity of the nanoparticle-TiO2 was compared with Degussa P-25 at optimum catalysis conditions determined for the nanoparticle-TiO2. It was concluded that when compared to Degussa P-25, the nanoparticle-TiO2 can be repeatedly used with increasing photocatalytic activity. The results revealed that the photodegradation of RB proceeds by pseudo first-order reaction kinetics in which the rate constant of the degradation is 0.132 min(-1).