Ce-doped titania nanoparticles: The effects of doped amount and calcination temperature on photocatalytic activity

Abstract

Abstract.A series of Ce-doped TiO 2 nanoparticles with different doped amount and calcination temperature were prepared by sol-gel method. These obtained samples were characterized with X-ray diffraction (XRD), transmission electron microscope (TEM) and ultraviolet-visible diffuse reflectance spectra (DRS), and their photocatalytic activities were evaluated by the photocatalytic degradation of methyl orange. Results showed that Ce doping inhibits the growth of crystal size and the phase transformation from anatase to rutile, leads to lattice distortion and expansion of TiO 2 . Furthermore, Ce doping brings the red-shift of absorption profile and the increase of photons absorption in the range of 400-600 nm. Photocatalytic degradation of methyl orange shows that Ce doping improves the photocatalytic activity of TiO 2 . The optimal doped amount is 0.05 mol% and the optimal calcined temperature is 600 o C for the maximum photocatalytic degradation efficiency in our experiment. IntroductionAs a promising photocatalyst, TiO 2 has been intensely researched for the treatment of environmental pollution in recent decades. However, there are still some problems which restrict its application in practical industry, such as restrictive light absorption due to its large band gap, the fast recombination of photo-generated electrons and holes [1]. Therefore, it is of great interest to develop new photocatalysts with visible-light response and effective separation of electron-hole pairs.Recently, some reports have demonstrated that doping TiO 2 with suitable metal or nonmetal ions is a useful strategy to improve the mentioned above two performances of TiO 2 [2]. Due to incompletely occupied 4f and empty 5d orbitals, rare earth metals are often used as catalyst or promote catalysis. Some results have shown that doping TiO 2 with rare earth metals or their oxides is an effective method to improve the photocatalytic activity of TiO 2 [3]. As one of the rare earth metals, Ce has been used as a dopant to enhance the photocatalytic activity of the TiO 2 [4]. However, there is an example that Cedoping brought negative effect on the photocatalytic performance of TiO 2 [5].In order to clarify the effects of Ce-doping, in current work, a series of Ce-doped TiO 2 nanoparticles with different doped amount and calcination temperature were prepared by sol-gel method. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and ultraviolet-visible diffuse reflectance spectra (DRS), and their photocatalytic activities were investigated by photocatalytic degradation methyl orange (MO) in water.

Effect of Rare-Earth Metal Oxide Nanoparticles on the Conductivity of Nanocrystalline Titanium Dioxide: An Electrical and Electrochemical Approach

“…Rare-earth metal oxides (REOs) have been used as dopants for titania to enhance photocatalytic activity − and photovoltaic performance of dye-sensitized solar cells (DSSCs). − Various mechanisms have been proposed for the observed improvement in DSSCs; however, in most of the reports, the effects are not quantitatively reproducible or thoroughly studied, resulting in a lack of clear understanding. In our previous report, we demonstrated a consistent efficiency improvement in dye-sensitized solar cells through REO doping and explained the improvement as being due in part to a decrease in impedance of the titania electrode caused by the filling of the deep trap states by the REO f-state electrons.…”