Simple and Efficient Aqueous Process for Nanostructured Fibrous TiO 2 Regulated by Linear Polyethyleneimine Aggregates

In this paper, we report a simple and smart biomimetic process for constructing TiO 2 nanofibers in aqueous system and its derivatives with Pt nanoparticles uniformly embedded inside. It was found that regularly structured TiO 2 ‐LPEI hybrids with fibrous networks could be easily produced when linear polyethyleneimine (LPEI) aggregates were used as a regulator in the hydrolytic condensation of water‐soluble titanium bislactates (TiLact). In the XRD patterns of the as‐prepared TiO 2 ‐LPEI hybrids, a strong peak appeared at a low diffraction angle of about 4°, which indicated the formation of regularly layered domains consisting of TiO 2 and LPEI residues in the fibrous hybrids. TEM observations showed that in the as‐prepared TiO 2 ‐LPEI hybrids very tiny crystallites less than 3 nm in size were closely packed to each other, whereas the crystalline domains increased to 10 nm after the hybrids were calcined at 500 °C. Raman spectroscopy measurement confirmed the existence of anatase phase in the as‐prepared hybrids. Simply mixing the TiO 2 ‐LPEI hybrids with an aqueous solution of PtCl 4 2– spontaneously resulted in the formation of Pt nanoparticles embedded in the TiO 2 ‐LPEI fibers. TEM images revealed that the Pt nanoparticles homogeneously distributed in the TiO 2 ‐LPEI hybrids without any damage to their fibrous morphologies. A typical photocatalysis evaluation revealed that under visible‐light irradiation the Pt‐embedded TiO 2 fibers exhibited two times higher activity in the photodecomposition of methylene blue than that of the pure TiO 2 fibers.