Synthesis of titania nanostructures and their application as catalyst supports for hydrogenation and oxidation reactions

Lucky M. Sikhwivhilu 

CSIR, Meiring naude, Pretoria 0001, South Africa

Abstract

Nanoparticles of titania promise to have diverse applications such as environmental cleaning and purification, photovoltaics, antifogging, self-cleaning surfaces, pigment, and cosmetic sunscreen emulsion, etc. Nanotubular structures are of great importance because of their exceptional electronic and mechanical properties. Over the years the synthesis of nanotubes of oxides such as TiO2 have attracted much attention and TiO2 nanotubes are particularly interesting because of their large specific surface area, which may influence photocatalytic activity and potentially lead to application in environmental purification. 

In our work TiO2 derived nanotubes with relatively large specific surface areas (~270 m2/g) were synthesized using a simple and short methodology. In order to understand the morphology, crystal structure, surface properties and the basic nature the materials were characterized by various techniques such as SEM, TEM, BET analysis, XRD, TPD and TPR. It has been found that the proportion, particle size, and the crystallinity of tubes formed depend on the synthesis conditions employed and that each material exudes unique properties. Composite materials with Au were synthesized by deposition precipitation (DP) method. Au supported on titania has been widely used in CO oxidation reactions, and numerous factors have been shown to enhance the activity of the Au/TiO2 catalyst including Au particle size. In the current study, we have used a titanate obtained from KOH/TiO2 as a support for the Au catalyzed CO oxidation reaction. We also report on the effect of morphological and structural modification of titania on the activity and stability of Au supported catalysts for CO oxidation. The effect of the tubular structures on Au particle size is addressed and compared with that of P25.

Pd nanoparticles were also incorporated into the TiO2 derived nanotubes and used as catalyst for the hydrogenation of phenol and ortho-chloronitrobenzene.

 

Presentation: Oral at E-MRS Fall Meeting 2007, Acta Materialia Gold Medal Workshop, by Lucky M. Sikhwivhilu
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-07-27 16:26
Revised:   2009-06-07 00:48