Metallorganic chemical vapor deposition and characterization of TiO2 nanoparticles

Abstract

TiO2 nanoparticles were synthesized using the metallorganic chemical vapor deposition process. Particles with and without metal ion dopants were obtained. X-ray photoelectron and energy dispersive X-ray spectroscopic measurements confirmed the stoichiometry of the TiO2 nanoparticles. X-ray diffraction patterns showed a polycrystalline anatase structure of TiO2. Transmission electron microscopy revealed that these particles are of nanoscale dimensions. Exact particle size and size distribution analyses were carried out by dynamic light scattering. The average particle size was determined to be 22 nm. The nanosize particles provided large surface area for photocatalysis and a large number of free surface-charge carriers, which are crucial for the enhancement of photocatalytic activity. To improve the photocatalytic activity, metal ions, including transition metal ions (Pd2+, Pt4+, Fe3+) and lanthanide ion (Nd3+) were added to pure TiO2 nanoparticles. The effects of dopants on photocatalytic kinetics were investigated by the degradation of 2-chlorophenol under an ultraviolet light source. The results showed that the TiO2 nanoparticles with the metal ion dopants have higher photocatalytic activity than undoped TiO2. The Nd3+ ion of these dopant metal ions showed the highest catalytic activity. The difference in the photocatalytic activity with different dopants is related to the different ionic radii of the dopants.