Apr 30, 2012
Environmentally friendly biomimetic synthesis of TiO2 nanomaterials with controlled crystal phase
The use of biomolecular structures such as viruses, proteins and DNA as biotemplates for the synthesis of nanomaterials has received a tremendous amount of attention from the scientific community. In a recent example, biomimicry has inspired the development of TiO2 nanomaterials. TiO2 is a superstar among transition metal oxides due to its wide use in both fundamental studies and practical applications.
Usually, titanium alcoxides are used as a titanium resource, but they are a kind of organic matter, and require carefully controlled conditions to obtain an amorphous gel.
Titanium trichloride, as a hydrosoluble inorganic salt, can be hydrolyzed to TiO2 in the atmosphere at room temperature and its hydrolysis rate is medium. These properties make it well suited to the demands of biomimetic synthesis. In addition, the crystalline TiO2 is generated at room temperature without any thermal treatment. If no template is added, rutile TiO2 is obtained, while adding albumen or yeast as a template gives a different result – the crystal phase of anatase emerges.
It appears that the crystal phase could be controlled just by using different biotemplates. The phenomenon is interesting and makes us bewildered. According to previous studies, there are several factors such as the concentration of reactant, pH value, temperature and the addition of impure anion or some surfactants that can generate SO42+ during the reaction. But it is clear that these influences are not suitable for our experiment.
Although in later research we found other biotemplates that could affect the crystal phase of TiO2, it is still difficult to explain why.
More details can be found in the journal Nanotechnology.
About the author
This work was performed in the Institute of Applied Chemistry at the University of Xinjiang. Prof. Shu-Juan Bao obtained her PhD at Lanzhou University and completed a postdoctoral fellowship at the School of Chemical and Biomedical Engineering, NTU. She is currently a professor at Xinjiang University, China. Her research interests include controllable synthesis and functionalization of nanomaterials, and their important applications in nanoelectronics, biomedical devices and energy systems such as fuel cell, battery and supercapacitor.