Uniform spherical- and rod-shaped TiO2 nanoparticles of anatase phase were prepared using decanoic acid at 300°C by reverse micelle method. The nanoparticles were characterized by transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffractometry (XRD) and FT-Raman spectroscope. The content of decanoic acid and operating temperature were noted as crucial parameters, controlling the shape, size and phase of TiO2 nanoparticles. RMS roughness (1.62 nm), measured by atomic force microscope (AFM), confirmed its superiority over other methods. The DCB photodegradation reaction rate constant (first order) TiO2 nanoparticles was found superior to that of commercial TiO2, Degussa P-25.