A One‐Step Approach to the Synthesis of High Aspect Ratio Titania Nanoflakes

Abstract

most synthesis methods for these types of particles require multiple, complicated synthesis procedures and are typically nonconductive to be scaled up manufacturing as yields are typically milligram or less quantities of material. Examples of this includes template, chemical vapor deposition, hydrothermal, electrochemical anodization, etc. [12][13][14][15] Almquist and Biswas prepared anatase powders with sizes ranging from 5 to 165 nm employing various synthesis methods and found that an optimum particle size range of 25-40 nm within all photocatalytic experiments regardless of fabrication processes. [16] The authors suggest that the optimum particle size is a function of several competing mechanisms such as light absorption and scattering efficiency of the particles, as well as electron-hole pair combination and interfacial charge transfer. Therefore, cost effective and mass production available synthesis for titania nanomaterials with at least 1D close to the optimum size of photocatalyst will be a revolution of the whole titania fabrication.In this study, micrometer sized titania flakes having a thickness ≈40 nm were successfully synthesized by spreading an oil phase consisting of titanium tetraisopropoxide and a low surface tension hydrocarbon on the surface of water. [17] These nanoflakes were produced by restricting the hydrolysis of titania precursor within dimension of the organic thin film due to the difference of surface energy to water. The flakes were also calcined at 400 °C resulting in high purity anatase having near identical dimensions to the uncalcined material. Investigations have shown the described method to be efficient and economical at producing gram to kilogram quantities of material. This study examines these nanoflakes which were characterized by scanning electron microscopy (SEM), laser diffraction analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM), physisorption techniques, and UV-visible spectrometer.The surface morphology of synthesized titania nanoflakes was investigated using SEM images, shown in Figure 1. The major diameter of the flakes was found to be of the order of 10-20 µm ( Figure 1A,B), and the thickness of these flakes was ≈40 nm (Figure 1C,D). The flakes were further treated by calcination at 400 °C for 2 h. Aggregation was not apparent when comparing these treated flakes ( Figure 1B) with those obtained directly from synthesis ( Figure 1A). Moreover, the thickness of calcined flakes did not change by the heat High aspect ratio TiO 2 nanoflakes are synthesized by a one-step modified surface hydrolysis method. Surface morphology and physical dimensions are characterized using scanning electron microscopy, laser diffraction analysis, and transmission electron microscopy. Microsized flakes having a thickness ≈40 nm are successfully synthesized by spreading an oil phase consisting of titanium tetraisopropoxide and a low surface tension hydrocarbon on the surface of water. Pure anatase phase crystalline titania nanoflakes are obtained by calcining at 4...