Microsoft word - shammi akter ferdousi phd thesis abstract

Department of Chemical and Biomolecular Engineering Hong Kong University of Science and Technology Spatial Doping of 1D Titanium Nanotubes
Shammi Akter FERDOUSI

Abstract

This research works has invented a novel general synthesis method for producing spatial doping in 1D titanium based
nanotubes. For this, we divided our works in two phases. In first phase of the works, we present general synthesis
methods for producing 1D Ti-based nanostuctures, more precisely, mainly nanotubes and elucidate their formation
mechanisms based on exsitu microscopic analysis and insitu spectroscopic analysis. Titanium based nanostructures
are produced from different Ti-sources by using alkaline microwave hydrothermal irradiation techniques. There are
number of factors that affect its nanostructure of this method. Post treatment washing is the main crucial step that
depends on some parameters which affects Ti-nanotube structure, morphology, crystal size, textural properties and
composition etc.
In second phase of works, we present, again, a new synthesis method to prepare metal and metal oxide, dye etc doped
on different spatial locations of the titania nanotubes (i.e. core, surface and interlayer spaces). The precursors are
introduced by either in-situ or ex-situ techniques to the titania precursor materials. Dopants from the Group IB, IIB, IVB,
V and VIII element including Ag, Au, Co, Cu, Pd, Pt and V and their oxides etc are successfully doped on the surface, in
the core and within the interlayer spaces of the titania nanotubes. The location of the dopants is manipulated by
controlling the affinity of the dopant precursor to the titania surface during the preparation. Precursor with low affinity
will preferentially decorate the nanotube surface, whereas strong affinity will lead to metal being embedded between
the interlayer spaces of the nanotube. Intermediate affinity allows core-filling to produce metal particles, slugs or
nanowires within the core of the nanotubes. Microscopy and spectroscopy studies are carried out to investigate the
structural, chemical and electronic properties of these new nanotube materials and explore to application for catalytic
conversions, biomedical applications etc.
To examine of as prepared doped Ti-nanotubes, visible light photocatalytic and antibacterial test have been done. Here
tried first, silver doped Ti-nanotubes that can apply for adsorption, UV and/or visible range photocatalyst or
antimicrobial properties. Application results found 100% adsorption ability for diclofenac sodium (DFS), an endocrine
disrupting compounds and 99% degradation ability for a model pollutant, 2,4 dicholorphenol compare to P25 (10%).
The samples can effectively works as a bacterial inhibitor and bactericidal properties for Staphylococcus aureus (S.
aureus) and Escherichia coli (E.coli). For E-coli 100% reduction activity is found. We vastly present the S.aureus
reduction activity under different conditions, such as, UVA, under dark and/or under lamp (screen lamp). Most cases S.
aureus reduction activity found 99.999%.
Date: 10 February 2014 (Monday)
Time: 15:00
Venue: Room 4577 (Lift 27-28)
Examination Committee:
Prof. Yijing YAN, Chairman
Prof. King Lun YEUNG, Supervisor
Prof. Guohua CHEN, Prof. Chi Ming CHAN, CBME
Prof. Joseph K. C. Kwan, HSEO
Prof. Jesus SANTAMARIA, University of Zaragoza
- ALL ARE WELCOME -

Source: http://www.cbme.ust.hk/shammi.pdf