Phase modulation kinetics in TiO2 by manipulating pH: A dynamic of photoactivity at different combination of phase and pH

A fundamental understanding of dynamism of charge-transfer characteristic at different phase and pH combination play an significant role for the development of highly efficient light harvesting photocatalyst. Herein, we describe the phase modulation at different pH and its relationship with the photocatalytic activities is emphasized. The pH of the precursor solution allows to control phase and size of TiO2 nanoparticles at constant temperature. The phase modulation at different pH proceeds through hydrolysis and polycondensation based on partial charge model. Rutile phase were formed at pH 3 of precursor solution. Anatase phase were formed at pH 9 while the mixed phase Anatase/Rutile formed at pH 5. A complementary role of phases on the catalytic activity of TiO2 under UV and visible irradiance was established using pseudo first order kinetics. This study was supported by XRD, HR-TEM, UV-DRS, XPS and FTIR analysis. This result gives a new strategy for controlled phase transition offset and size of TiO2 nanoparticles by manipulating pH.