Immobilized Enzymes for the Room Temperature Synthesis of TiO2 Nanostructures

Through billions of years of evolution, organisms have developed elegant mechanistic pathways to synthesize the full range of molecules necessary for life. Many of these molecules can be used outside of the cellular environment, their specific functionality being exploited to perform tasks beyond the reach or conventional chemistry. Because they are operational at atmospheric pressure and room temperature, adaptation of biomacromolecules in the form of enzymes can potentially replace current energy intensive synthesis methods for metal oxide semiconductors. In this work, the enzyme urease is used to induce localized pH changes in solution, thereby initiating the nucleation and growth of TiO2 nanostructures with controlled size and morphology. These reactions use benign conditions, where temperatures of 150ºC or higher would normally be necessary. Controlled-size TiO2 structures can be applied to numerous current engineering problems such as improving dye-sensitized solar cells and UV-initiated catalysis.