Preparation Of Nano/Micro-hierarchical Architectures TiO₂Photocatalyst

As an important inorganic functional material, Titania （TiO₂）has many uniquephysical and chemical properties. This material is extensively used as a catalyst inpurification of air and water, a pigment in making paints, an enamel, an antimicrobialand so on. TiO₂powders are usually restricted by some performances in theapplication because they are easier to become inactive, to reunite and harder to bereclaimed in the photocatalytic process. This article discusses the disadvantages ofnanosized TiO₂issue of a series of research and exploration. The combination ofnano-sized TiO₂and CuO semiconductors materials and the fabrication ofhierarchically TiO₂are emphatically researched. The main contents include thefollowing:Firstly, the nano/micro-structures TiO₂/CuO complex had been fabricated via thehydrolyzation method in the surface adsorption layer. Their structures, morphologiesand surface compositions were characterize by XRD, SEM,and EDS techniques.Theresults indicated that homogeneous TiO₂nanoparticles coudld be formed on thesurfaces of CuO microspheres. The photocatalytic activity of TiO₂/CuO comples wasstudies primarily.Secondly, TiO₂with hierarchical architectures, tunable crystalline phase andthermal stability is successfully fabricated on a large scale through a facile hydrolysisprocess of TiCl4combining with inducing of pollen. The structure of the as-preparedTiO₂is characterized by X-ray diffraction, Raman spectroscopy, infrared spectra, andscanning electron microscopy. The experimental results indicate that different phases（anatase, rutile or mixed crystallite） of TiO₂can be synthesized by controlling thesynthesis conditions. The pure phase of rutile or anatase can be obtained at100℃,while the pure phase of anatase can be retained after being annealed at900℃. Thenano-particles or nano-rods of TiO₂, as building blocks, assemble to the hierarchicalTiO₂micro-sized materials, which exhibit reused photo-catalytic properties fordegradation of methylene blue. These hierarchical TiO₂microspheres should havegreat applications in photo-catalysis, catalysis, solar cells, separation and purification processes. This study provides an example for better understanding the formationmechanism of other inorganic hierarchical materials in the presence of pollen. Webelieve that the present work will open up systematically explore ways to fabricatehierarchical structures and thus find use in a variety of applications.