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.

Biomimetic synthesis

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.