Difference between Anatase and Rutile Titanium Dioxide (TiO2) Nanoparticles

Titanium oxide is the one of the top 50 chemicals which are produced in worldwide. It occurs in nature in three forms anatase, rutile and brookite. However, commonly, anatase and rutile forms have been used and studied. Naturally, it has whitish and opaque appearance, and through purification, it becomes whiter. Difference in crystal structure of these two forms as you can see in Figure 1 aroused interest in discrepancies between these forms, and many studies have been conducted.

Figure 1: Crystalline structure of titanium dioxide anatase (a) and rutile (b) Ti and O atoms are represented in white and red respectively.

P. Mazzolini, Functional Properties Control of TİO2 for Transparent Electrodes and Photoanodes, 2015

Difference between Characteristics of Rutile and Anatase TiO2 Nanoparticles

In general, scholars studied comparison of photocatalyst and carcinogen characteristics, and production methods between anatase and rutile forms of titanium dioxide nanoparticles. First of all, there is a band gap difference, and anatase has about 3.2 eV band gap, and rutile has about 3.0 eV band gap. Since absorption is inversely proportional to band gap, rutile can absorb more light than anatase. According to photoconductivity measurements, electron-hole pair life time is in anatase is longer than one in rutile, so more charge carriers in anatase participate in surface reactions. In addition, there are researches about toxicology of anatase and rutile titanium dioxide nanoparticles in particular subjects. Results show that anatase is more toxic than rutile. These are the fundamental comparisons, but there are also difference in usage and applications which are both rutile and anatase forms are used.

In a study, N.-G. Park, J. van de Lagemaat, and A. J. Frank working about Comparison of Dye-Sensitized Rutile- and Anatase- Based TiO2 Solar Cells concluded that the short-circuit photocurrent of the rutile-based cell is about 30% lower than anatase-based cell. Another scholars studied on different toxicity of rutile and anatase TiO2 nanoparticles on macrophages: Involvement of difference in affinity to proteins and phospholipids, and the conclusion is that with similar size and zeta potential, rutile and anatase titanium dioxide have different damage effect on organelles in macrophages and different toxicity. The rutile nanoparticles have a high affinity to phospholipids while the anatase nanoparticles have high affinity to proteins.

These differences enhance the range of applications of titanium dioxide nanoparticles. In some applications the difference become an advantage, and both forms are used. Many such applications will be found and developed using the discrepancies.

Molybdenum Trioxide Nanoparticles/Nanopowder and Applications

General Information about Molybdenum Trioxide Molybdenum trioxide is chemical compound with the formula MoO3. Its chief application is as an oxidation catalyst and as a raw material for the production of molybdenum metal. Molybdenum Trioxide is a very light blue powder. Molybdenum Trioxide Nanoparticles/Nanopowder and Their Applications Like many nanoparticles/nanopowder , Molybdenum Trioxide nanoparticles/nanopowder are used as catalysts. These catalysis reactions include hydrogenation catalysis and cracking catalysis. Molybdenum Trioxide nanoparticles/ nanopowder are useful for...

Rundown about Silicon Oxide Wafer

The main insulating material used in micro-technology is Silicon Dioxide, which in chemical symbols is written as SiO2. In semiconductor technology, SiO2 thin film layers are mainly used as dielectric material film in transistors, capacitors (DRAM) or flash-memories. Silicon Oxide Wafers are produced using crystallization, solid state and other ultra-high purification processes such as sublimation. This process forms a cylindrical ingot, which is then sliced and polished to form wafers. Thermal oxide is a kind of "grown" oxide layer, compared to CVD deposited oxide layer, it has a higher uniformity, and higher dielectric strength, it is an excellent dielectric layer as an insulator . In most silicon- based devices, thermal oxide layer play an important role to pacify the silicon surface to act as doping barriers and as surface dielectrics. The simplest way to produce an insulating silicon oxide layers (SiO2) on silicon wafers is to oxidize silicon with oxygen, which ...

Hydroxyapatite Nanopowders and Their Applications

Hydroxyapatite, is a naturally occurring mineral form of calcium apatite with the formula Ca 5 (PO 4 ) 3 (OH). Pure hydroxyapatite powder is white. Naturally occurring apatites can, however, also have brown, yellow, or green colorations, comparable to the discolorations of dental fluorosis. Hydroxyapatite Nanopowder/Nanoparticles (50 nm, 99.95+%) has been widely used as a biocompatible ceramic in many areas of medicine, but mainly for contact with bone tissue, due to its resemblance to mineral bone. In mammals, the skeleton presents a carbonated and partially substituted apatite, based on nanocrystal aggregates, and associated with collagen, building up 3-D structures present in various bone tissue conformations like trabecular or cancellous bone. There has been growing interest in developing bioactive synthetic ceramics that could closely mimic natural apatite characteristics. As mentioned before, Hydroxyapatite Nanopowder is the main inorganic constituent of bon...

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