Photocatalytic Titanium Dioxide, ST/STS Series
Titanium Dioxide exhibits strong oxidizing photoactivity when irradiated by UV ray.
The surface of pigmental titanium dioxide used for paints and plastics is usually treated with inorganic compounds (partially with organic compound) to restrain the photoactivity. Photocatalytic titanium dioxide utilizes the photoactivity at the most.
With the light energy, photocatalyst decomposes pollutants and malodors mainly made of organic compounds into carbon dioxide and water. By super-hydrophilicity induced by light energy, affinity to water increases and anti-fogging effect, anti-stain effect and self-cleaning effect can be imparted. In addition, this photoactive reactions can last by its regenerating property.
ISK's photocatalytic titanium dioxide ST, STS products are manufactured in ISK's original technology to further enhance photoactivity.
(Visible light photocatalyst)
ISK has newly developed visible light photocatalytic powder (preliminary sample:MPT-623). Due to excellent sensitivity to visible light, photoactivity can be obtained by not only sun light but also by fluorescent light. With the sensitivity, this photocatalyst is expected to be used for more versatile applications.
Click the flame below (in the flame below with)
- Photocatalytic Powder ST Series
- Photocatalytic Hydrosol STS Series
- The mechanism of photocatalysis and Characteristics of photocatalytic TiO2 and photo-hydrophilic function
Photocatalytic Powder ST Series
1. Characteristics of ST series
Various grades with different particle size and adsorption properties are available.
|ST-21||20||50||○||high activity and dispersibility|
|ST-31||7||250||○||excellent gas absorption|
2. Electron Micrographs of ST series
3. Photocatalytic properties of ST series
in gas (acetaldehyde)
- amount of TiO2: 0.1g
light source intensity: black light 0.5mW/cm²
irradiation area: 24cm²
reaction volume: 2.8L
in liquid (2-propanol)
- amount of TiO2: 4g/L
light source intensity: black light 2mW/cm²
irradiation area: 24cm²
reaction volume: 80mL
Photocatalytic Hydrosol STS Series
Acidic and neutral sols are available.
|grade||TiO2content (wt%)||X-ray particle size (nm)||pH||characteristics|
|STS-01||30||7||1.5||acidic with nitric acid, excellent dispersibility|
|STS-02||30||7||1.5||acidic with hydrochloric acid, excellent dispersibility|
The mechanism of photocatalysis and Characteristics of photocatalytic TiO2 and photo-hydrophilic function
A typical semiconductor, TiO2, creates holes and electrons by irradiating light with higher energy than TiO2's band gap energy (wave length < 380nm). The holes and electrons react with oxygen and hydroxyl ions, producing hydroxyl radicals and superoxide anions. Oxidation power of the chemicals are so strong that the chemicals decompose and eliminate organic compounds and NOx.
2. Characteristics of TiO2 photocatalyst.
- High oxidizing ability
As oxidative OH radicals produced by TiO2 photocatalysis have high oxidation potential shown in Table.1, TiO2 photocatalyst exhibits high oxidizing ability.
- Chemical stability
TiO2 is chemically stable and not dissolved in water, although some other semiconductive photocatalytic compounds are dissolved when irradiated in water. TiO2 is so chemically stable that it is not dissolved in almost all acidic, basic and organic solvent.
TiO2 is regarded as a safe and inert material in general.
Table 1 Comparison of oxidation potential of various oxidizing agents.
|Oxidizing agent||Reaction||Oxidation potential (V)|
3. Photo-induced super-hydrophilicity
The surface coated with photocatalytic TiO2 shows super-hydrophilicity by UV irradiation. On the super-hydrophilic surface, adsorbed water does not create dew but become thin layer. Thus, the surface exhibits anti-fogging effect and gets uneasy to be attached by stain itself. Furthermore, the surface becomes easy to wash away attached stain by water.
- Titanium Dioxide Products
- Functional Materials
- Environmental Products
- Heat Shield Materials
- Animal Health Products
- Organic Intermediates