(148a) Biologically Inspired Synthesis of Nanostructural Titanium Dioxide for Photocatalytic Applications

There is a rapid increase in emerging contaminants from both industrial and pharmaceutical sources causing concern over water quality and its affect on public health and safety. A number of processes have been developed to treat our water, one of which is using photocatalysts that accelerate organic degradation. TiO2, as a photocatalytic material, shows great potential for being able to completely mineralize a wide variety of compounds. TiO2 can also be used in many different applications such as photovoltaics and photocatalysts, as well as applications in cosmetics, sunscreens, and paints. Many of the synthesis methods used to TiO2 require high temperatures or extreme pH's to achieve the desired phase, shape, and size of the material. However mineralizing biological systems demonstrate how nature can produce elegant structures at room temperature through controlled organic-mineral interactions. These organics exist as either soluble forms or as insoluble scaffolds that are often used to control size, shape, and orientation of mineral.

We are using biologically-inspired scaffolds to template the nucleation and growth of inorganic materials such as TiO2. These ligands (modeled after specific mineral functionalities identified in biomineral systems) interact with minerals during nucleation and growth can be help to control the size, shape, and phase of these particles and ultimately, their properties. Understanding the fundamental nucleation and growth mechanism is critical to control the microstructure and therefore function. Nanosized rutile and anatase particles were synthesized using a biologically inspired method at relatively low temperatures and mild pH conditions. The effects of reaction conditions on phase and grain size were investigated and discussed from coordination chemistry and coarsening mechanisms. We demonstrate the control over the size and phase of the TiO2 nanostructures which resulted in enhanced photocatalytic degradation of an organic dye.