Study of [Nd.sup.3+], [Pd.sup.2+], [Pt.sup.4+], and [Fe.sup.3+] dopant effect on photoreactivity of Ti[O.sub.2] nanoparticles

The metallorganic chemical vapor deposition method was successfully used to synthesize pure Ti[O.sub.2] and [Nd.sup.3+]-, [Pd.sup.2+]-, [Pt.sup.4+]-, and [Fe.sup.3+]-doped Ti[O.sub.2] nanoparticles. Polycrystalline Ti[O.sub.2] structure was verified with x-ray diffraction, which showed typical characteristic anatase reflections without any separate dopant-related peaks. Transmission electron microscopy observations confirmed the existence of homogeneously distributed 22 [+ or -] 3 nm Ti[O.sub.2] nanoparticles. The particle size remained the same for the doped samples. The doping level of transition metals was kept at [approximately equal to] 1 atomic percent, which was determined by x-ray photoelectron spectra and energy dispersive x-ray spectroscopy. The effects of different types of dopants on the photocatalytic activity were revealed by the degradation of 2-chlorophenols with an UV light source. The photocatalytic efficiency was remarkably enhanced by the introduction of [Pd.sup.2+] and [Nd.sup.3+]. [Nd.sup.3+]-doped Ti[O.sub.2] showed the largest enhancement. However, [Pt.sup.4+] changed the 2-chlorophenol degradation rate only slightly, and [Fe.sup.3+] was detrimental to this process. These effects were related to the position of the dopants in the nanoparticles and the difference in their ionic radii with respect to that of [Ti.sup.4+].