We prepared ZnO ultrafine particles (UFPs) by thermal decomposition of the precursor zinc carbonate hydroxide. The surface properties of the as-prepared particles were studied using TEM, XRD, BET, SPS, EPR, IR, and XPS. The surface contains active species such as oxygen deficiencies and hydroxyl that improve photocatalytic activities. The concentrations of active species decreased as the calcination temperature increased along with the surface areas and photovoltage. The ZnO UFP have a significant EPR signal resulting from O2 deficiencies on the surface, which can capture and trap alectrons. Dining photocatalytic degradation of phenol, the photocatalytic activities of the particles decreased as their size increased, which means that these activities depend mainly on surface properties.

The pure, 1 mol% only La or only Cu doped TiO2 and La and Cu codoped TiO2 were prepared by a sol-gel process. The effects of doping on photoinduced charge properties of nanosized TiO2 were mainly investigated by means of Surface Photovoltage Spectrum (SPS) and Photoluminescence Spectrum (PL), together with their relationships with photocatalytic activity. The results show that La dopant can inhibit the phase transformation of TiO2, meanwhile improve the separation rate of photoinduced charge carriers, and enrich the binding surface states. However, Cu dopant has a reverse effect compared to La dopant. This is responsible for the results that doping La is favorable for the increase in the photocatalytic activity for degrading the RhB solution, while doping Cu is bad to photocatalyitc reaction. In addition, codoping La and Cu cannot exhibit an obvious combination effect.

In this paper, pure and La doped TiO2 nanoparticles with different La content were prepared by a sol-gel process using Ti (OC4H9)4 as raw material, and also were characterized by XRD, TG-DTA, TEM, XPS, DRS and Photoluminescence (PL) spectra. We mainly investigated the effects of calcining temperature and La content on the properties and the photocatalytic activity for degrading phenol of as-prepared TiO2 samples, and also discussed the relationships between PL spectra and photocatalytic activity as well as the mechanisms of La doping on TiO2 phase transformation. The results showed that La3+ did not enter into the crystal lattices of TiO2 and was uniformly dispersed onto TiO2 as the form of La2O3 particles with small size, which possibly made La dopant have a great inhibition on TiO2 phase transformation; La dopant did not give rise to a new PL signal, but it could improve the intensity of PL spectra with a appropriate La content, which was possibly attributed to the increase in the content of surface oxygen vacancies and defects after doping La; La doped TiO2 nanoparticles calcined at 600℃ exhibited higher photocatalytic activity, indicating that 600℃ was an appropriate calcination temperature. The order of photocatalytic activity of La doped TiO2 samples with different La content was as following: 141.54340.54540 mol%, which was the same as the order of their PL intensity, namely, the stronger the PL intensity, the higher the photocatalytic activity, demonstrating that there were certain relationships between PL spectra and photocatalytic activity. This could be explained by the points that PL spectra mainly resulted from surface oxygen vacancies and defects during the process of PL, while surface oxygen vacancies and defects could be favorable in capturing the photoinduced electrons during the process of photocatalytic reactions.

In this paper, ZnO ultrafine particles (UFPs) were prepared by the thermal decomposition method of the precursor, zinc carbonate hydroxide. The structure and properties of the as-prepared ZnO UFPs were studied using TEM, XRD, BET, SPS, ESR, Raman, XPS and UV-Vis absorption spectroscopy. It was found that the prepared ZnO UFPs exhibited obvious quantum size effect and surface effect. In addition, there were many active species on the surface of ZnO UFPs such as oxygen deficiencies and hydroxyls, both of which can improve the photocatalytic activities of ZnO UFPs.