Low-Temperature Synthesis of Anatase TiO(2) Nanoparticles with Tunable Surface Charges for Enhancing Photocatalytic Activity

In this work, the positively or negatively charged anatase TiO(2) nanoparticles were synthesized via a low temperature precipitation-peptization process (LTPPP) in the presence of poly(ethyleneimine) (PEI) and poly(sodium4- styrenesulfonate) (PSS). X-ray diffraction (XRD) pattern and high-resolution transmission electron microscope (HRTEM) confirmed the anatase crystalline phase. The charges of the prepared TiO(2), PEI-TiO(2) and PSS-TiO(2) nanoparticles were investigated by zeta potentials. The results showed that the zeta potentials of PEI-TiO(2) nanoparticles can be tuned from +39.47 mV to +95.46 mV, and that of PSS-TiO(2) nanoparticles can be adjusted from −56.63 mV to −119.32 mV. In comparison with TiO(2), PSS-TiO(2) exhibited dramatic adsorption and degradation of dye molecules, while the PEI modified TiO(2) nanoparticles showed lower photocatalytic activity. The photocatalytic performances of these charged nanoparticles were elucidated by the results of UV-vis diffuse reflectance spectra (DRS) and the photoluminescence (PL) spectra, which indicated that the PSS-TiO(2) nanoparticles showed a lower recombination rate of electron-hole pairs than TiO(2) and PEI-TiO(2).