Peptide-Templated Synthesis of TiO2 Nanofibers with Tunable Photocatalytic Activity

Nanofabrication based on biological templates has attracted considerable interest because of its applications in materials science and biomedicine. Herein, a facile method is reported for the synthesis of well-defined TiO2 nanofibers by using a simple N-(9-fluorenylmethoxycarbonyl)-protected phenylalanine-phenylalanine-aspartic acid tripeptide (Fmoc-Phe-Phe-Asp-OH, Fmoc-FFD) as the template. Compared with other synthetic methods of inorganic nanomaterials, these self-assembling peptides could control the structure and the catalytic activity of the synthesized nanomaterials produced under mild synthetic conditions. The as-synthesized peptide-TiO2 hybrid nanofibers and the calcined TiO2 nanofibers were characterized by using transmission electron microscopy (TEM), scanning electron microscopy (SEM), circular dichroism (CD) spectroscopy, and X-ray diffraction (XRD). The results show that well-defined TiO2 nanofibers could form when the pH of the peptide solution was 5-7, whereas nanoparticles formed when the pH was 8. Moreover, the peptide-templated TiO2 nanofibers showed improved photocatalytic activity for the degradation of methyl orange (MO). Finally, the photocatalytic activity of the TiO2 could be controlled by adjusting the pH of the peptide solution during the synthetic process.