Influence of temperature and surfactant on the photocatalytic performance of TiO₂ Nanoparticles

Synthesis of TiO₂ nanoparticles were performed by hydrothermal and sol-gel methods under 150 °C and 50 °C, respectively. The characteristic of different samples derived from different methods are compared. The effect of various parameters like temperature and surfactant (cetyltrimethyl ammonium bromide and urea) has been carried out in order to attain optimized pore morphology, high crystallinity, and to find desired adsorption condition. With the temperature increasing and surfactant applying, the morphology changed from equiaxed shape (T1) to cubic (T2) and rectangular shape (T3), and the particle size, crystal size and pore size show an increasing trend. Under the low temperature, the prepared nanoparticles are closed to single crystal morphology, but the samples possess polycrystalline morphology after the temperature increasing and surfactant applying. The photocatalytic activity was examined by degradation of Methylene blue under Xenon lamp and compared with P25. We found that those high-temperature synthesized samples exhibit significantly higher photocatalytic activities than the sample synthesized under low temperature so that the raspberry-like sample with the highest particle size displays dramatically (prominently) better photocatalytic activity higher than P25. This study provides a simple and inexpensive way to prepare high active anatase TiO₂.