(583ek) Silver Doped in Spatial Locations of Titanate Nanotubes and Its Role On Activity

Sim, V., The Hong Kong University of Science and Technology
Ferdousi, S. A., The Hong Kong University of Science and Technology
Ching, W. K., The Hong Kong University of Science and Technology
Yeung, K. L., The Hong Kong University of Science and Technology

One dimensional (1D) nanostructures including titanate nanotubes can exhibit unique physical, chemical, electronic and catalytic properties that find applications in energy, catalysis, electronics and medicine. The transformation between two dimentional (2D) titanium precursor sheets into 1D nanotubes has been subject of many studies. Current researches on 1D titanate nanostructures open up opportunities to confine secondary materials, providing an interesting route to tune up catalytic properties and performances. Generally, transition metal doping in titanate nanotubes is enormous due to the change in surface chemistry that could modify morphology, electronic or spectroscopic properties, resulting in changed catalytic efficiencies. Structural details related to catalytic properties and active adsorption sites in metal doped titanate nanotubes or other nanostructured materials are not yet known and required further research.

In this study, visible light active photocatalysts were prepared by spatial doping with titanate nanotubes in the core and the interlayer spaces of the titanate nanotubes or on its surface. This work is first in a series of materials created using a new synthesis method. The titanium-containing precursor was first converted into an intermediate layered nanostructure followed by their exfoliation and conversion into nanotube structure. Silver precursors with different affinity are doped with the layered nanostructure via insitu and exsitu techniques that could control the spatial location of the silver in the final nanotube. Depending on the location of the silver dopant, the Ag-doped titanate nanotubes exhibit unique structural, chemical, electronic and photocatalytic properties.

The prepared photocatalyst effectiveness was studied for adsorption and photocatalytic performance under visible light. An endocrine disrupting compound (diclofenac), an organic pollutant (2,4 dichlorophenol) and dyes were used as model pollutants for this study. The results show that the silver-containing nanotubes exhibit adsorption (100%) and excellent photocatalytic performance (91%) compared to commercial P25 (13%).