Synthesis and characterization of TiO2 and TiO2/Ag for use in photodegradation of methylviologen, with kinetic study by laser flash photolysis

This paper reports the synthesis, characterization, and application of TiO 2 and TiO 2 /Ag nanoparticles for use in photocatalysis, employing the herbicide methylviologen (MV) as a substrate for photocatalytic activity testing. At suitable metal to oxide ratios, increases in silver surface coating on TiO 2 enhanced the efficiency of heterogeneous photocatalysis by increasing the electron transfer constant. The sol–gel method was used for TiO 2 synthesis. P25 TiO 2 was the control material. Both oxides were subjected to the same silver incorporation process. The materials were characterized by conventional spectroscopy, SEM micrography, X-ray diffraction, calculation of surface area per mass of catalyst, and thermogravimetry. Also, electron transfers between TiO 2 or TiO 2 /Ag and MV in the absence and presence of sodium formate were investigated using laser flash photolysis. Oxides synthesized with 2.0 % silver exhibited superior photocatalytic activity for MV degradation.