Evaluation of doped-titania photocatalysts for aqueous glycerol degradation and hydrogen production under visible light illumination

Abstract

This study describes a new method for enhancing photocatalytic activity of TiO2 under visible light with wetness impregnation method. Higher doping of Cobalt compared to Platinum in support Titania contributed to reducing commercial problem in catalyst preparation. A number of methods were utilized for characterizing catalysts such as: Brunauer, Emmett and Teller (BET), X-ray Diffraction (XRD), Thermal Gravity calcination (TGC), UV-Vis, UV-Fluorescence. From the result, the Co/TiO2 and Pt/TiO2 properties were improved for them to be more active in visible irradiation and performed high efficiency in photocatalytic activity. However, in wetness impregnation method, the conductivity level of Cobalt is lower than Platinum so Cobalt doped TiO2 was not suitable in hydrogen production area even though the percentage of Pt loading is minor compared to Cobalt. In addition, in 1.25 bubble column reactor was modified to appropriately work in this study. All of gas gauss meters were changed to mass flow control for precious measurement. In this reactor, two experiments which are glycerol degradation and glycerol to hydrogen under visible light were implemented. On the one hand, the Co/TiO2 was utilized for testing glycerol degradation. With the 8% of cobalt loading and pre-calcination at 773K, the catalyst exhibited a high productivity in photodegradation of glycerol. On the other hand, Pt/TiO2 conducted investigation of hydrogen generation. 0.2%wt Pt doped Titania which was calcinated at 773K in basic environment, presented a significant yield in generating hydrogen. In addition, there are some essential component in bubble column reactor were evaluated for optimizing the hydrogen productivity in this reactor. As a result, the pH environment, catalyst loading and total flow rate are the key factors which directly affect the hydrogen generation. The reaction which was implemented at pH 11, 1g.L-1 of catalyst loading and 1200 mil.min-1 of total flow rate is the optimum condition of hydrogen production when utilizing Pt/TiO2 in this reactor.