The American University in Cairo, Egypt
Title: TiO2-Graphene Oxide (GO) Nanocomposites: Synthesis, Environmental Applications and Surface Characterization using Perichromism
Biography: Amr Mohamed Tayel
TiO2-graphene oxide (GO) nanocomposites were successfully synthesized using a simple mixing and sonication sol-gel method with varying the rate of hydrolysis of the TiO2 precursor. The average particle sizes of the nanocomposites were 436 ±59 nm and 251 ±32 nm for the samples denoted TL and TS which corresponds to large particle size TiO2 and small particle size TiO2, respectively. The photocatalytic activity of the as-prepared TiO2-GO nanocomposites for methylene blue (MB) degradation was investigated under UV (λ=365 nm) light irradiation. The results showed that TiO2-GO nanocomposites have significantly higher photocatalytic activity than blank TiO2 (no GO). The increase in the photocatalytic activity of the samples was dependent on a number of factors such as surface acidity, surface area and the change in band gap energy. The surface acidity was measured using perichromic dyes and NH3- TPD; both measurements are independent. The increase in overall surface acidity after the GO addition was mostly attributed to Brønsted acidity as Lewis acidity was generally lower than the blank in most samples. However, possible stacking of GO at higher concentrations resulted in the decrease in overall acidity with the increase in GO contents. Surface polarity and polarizability were investigated using perichromic dyes to study their impact on the photocatalytic activity. Other surface properties were evaluated using BET, DRS-UV, FTIR, Raman and XRD. This study provides new insights on the surface characterization of high-performance photocatalysts used in wastewater treatment, correlating these surface properties and photocatalytic activity.