Fabrication of Micrometer‐Scale Anatase‐Phase TiO₂ Congeries Assembled with Hollow Spheres

Abstract

Micrometer‐scale anatase‐phase TiO2 congeries assembled with hollow spheres have been synthesized by a bubble‐template method combined with a facile chemical process. The as‐prepared products were characterized by means of X‐ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. Some of the congeries exhibited unique three‐dimensional hierarchical architectures. The bubble‐template strategy used in the synthetic process may represent a general approach to fabricate hollow micro‐ and nanostructures and therefore contribute to the formation mechanisms of hollow micro‐ and nanostructures.

Mixed Solvents Assisted Flame Spray Pyrolysis Synthesis of TiO2 Hierarchically Porous Hollow Spheres for Dye-Sensitized Solar Cells

“…Many different approaches, such as ultrasonic spray pyrolysis, Ostwald Ripening, sol–gel, template method and hydrothermal method, have been developed to prepare metal oxide semiconductor hollow spheres. − Conventional methods for the preparation of metal oxide semiconductor hollow spheres usually require removable or sacrificial templates to guide the formation of inorganic nanoparticles on their surfaces. However, the use of templates usually suffers from disadvantages of high cost and tedious synthetic procedures.…”

Hydrothermal Synthesis of TiO2 Porous Hollow Nanospheres for Coating on the Photoelectrode of Dye-Sensitized Solar Cells

“…4) It is also anticipated that both higher energy conversion efficiency and photocatalytic activity could be achieved by using the titania hollow microspheres instead of bulk titania as a photocatalyst. 5,6) There are several chemical and physicochemical methods which are used for preparation of the TiO 2 hollow nanospheres such as cationic colloidal particles for titania-coated polymeric nanoparticles, 7) a combination process containing hydrolysis of tetra-n-butyl in mixed solution of anhydrous ethanol/ammonia and subsequent calcination process, 8) reactive micro-emulsion precipitation 9) and sol gel process, 10) bubble-template method combined with a facile chemical process, 11) acid catalytic hydrolysis and hydrothermal treatment, 12) facile and large scale synthesis by hydrothermal method, 13) carbon spheres, 14) spheres of bacteria, 15) chemical vapor deposition (CVD) technique, 16) template-free green wet-chemical route, 17) spray pyrolysis using p123 pluronic block copolymer, 18) three dimentional (3D) architecture of TiO 2 hallo spheres by surface erosion route, 19) PEG-400 polymer-induced anatase TiO 2 hallow structures, 20) Mixed-phase titania nanospheres by laser ablation 21) and CuO used as a template in microwave heating method. 22) Typically, bilayered TiO 2 structures consisting of a main TiO 2 layer prepared from the tiny nanoparticles (10-30 nm) and a light-scattering layer (LSL) from the large particles (200-400 nm), have been designed for efficient utilization of the solar spectrum and enhancement of photovoltaic conversion efficiency ().…”

Intelligent Hydrated-Sulfate Template Assisted Preparation of Nanoporous TiO2 Spheres and Their Visible-Light Application

“…Currently, the general synthetic strategy for the preparation of hollow spheres is the utilization of templates, including “hard” ones, such as polymers, , silica, carbon, and metallic cores, as well as “soft” ones, for instance, emulsion droplets, micelles, microfluid, and gas bubbles. , These reported methods, although easily implemented, however, are incapable to readily tune the interior structures and the compositions. Therefore, it is highly desirable to develop a novel synthesis method using an intelligent template, which (i) is the water supplier for hydrolysis reaction, (ii) can control the structures and compositions by simply adjusting the reaction conditions, (iii) has a broad scope of application, (vi) is easily removed from the final products, and (v) is earth-abundant and environmentally benign.…”