01
Aug
07

what is hydrosyntetic photocatalyst?

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Innovation in TiPE™

Nano Hydro-synthesis Technology
New generation of nano particle dispersal technology. By using the latest theory in coordination chemistry, greatly reduced the reunification of nano crystallite in dispersed system, to form highly decentralized and stabilized water solution with low reunification, therefore, the product is more efficient and stable.

Avalanche Critical Temperature Nano Crystal Synthesis Technology
By switching the temperature from high critical temperature to low critical temperature rapidly in the process of nano particle synthesis, nano particle formed faster and reunited less. This technology makes the nano particle in fine crystal structure meanwhile in quantum scale size.

Ion Template Induced Low Temperature Crystallization Technology
The limit of crystal reunification as it must be calcined in high temperature or formed through hydration heat in traditional technique has been broken by advanced low temperature crystallization technology, the size of nano particle is greatly reduced, and 1.6nm of particle size at advanced international level has been achieved in our lab. The particle size of most products in our factory is less than 7nm currently.


Photo Induced Electron & Hole Capture and Separation Technology

By using of featured hole & electron capture agent, the compound between hole and electron in crystal body is greatly reduced, therefore the product performance is improved.

High Fermi Level Metal Nano Electrode Doping Technology
By using nano metal electrode aggradation technology, to aggregate high Fermi level metal electrode at the surface of nano crystallite, hence to greatly improve product performance and to greatly improve the utilization of visible light. Meanwhile, as high Fermi level nano electrode could effectively separate electron-hole pair to form micro zone dual cooperative effect on the surface, which makes the product could be maintained at highly stable active state for longer time work.

Nano Silver Composition Anti-bacterial Enhance Technology
Nano Silver doping technology could provide powerful anti-bacterial and anti-mold function without light, which greatly expanded the application of photocatalyst products in anti-bacterial. Meanwhile, free from toxin and side-effect is the obvious advantage for photocatalyst to be a next generation of broad-spectrum antibacterial product.

VLR(Visible Light Response) Photocatalyst Synthesis Technology
With special doping technology, replaced part of titanium by special ions and make it consolidated in nano titanium dioxide crystal structure. As the replaced special ion could change the crystallite density, the upper and lower limits of transition gap are changed, therefore the absorption photo spectrum is up lifted, which could fully make use of the energy in visible light spectrum, and the performance under visible light is much higher than traditional UV photocatalyst product.
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What’s Hydrosynthetic Photocatalyst?

The traditional nano photocatalyst manufacture technology divides into two parts. The first step is the manufacture of the nano titanium dioxide crystal. The second is the dispersion of the sol. Since only the nano titanium dioxide with Anatase structure has the photocatalytic performance, its manufacture process must include the calcining at high temperature and crystallization. However, the high temperature will greatly affect the nano level. Therefore the particle of normal nano titanium dioxide powder is not as small as the one produced by hydrosynthesis technology. The powder produced by high – energy ball milling is even far away from that of hydrosynthesis technology in crystallization degree and particle size. During the dispersion process, the synthetic nano titanium dioxide sol should be dispersed by adjusting PH value and adding surface active agents, which may bring some impurity in the sol. Most surface active agents as dispersant have biologic toxicity, which may cause extra pollution. The solid nano titanium dioxide particle may get reunited during the process of calcining and crystallization, which will affect its quality and property. When the solid nano titanium dioxide be dispersing into sol, the reunited particle can¡¯t be recovery and this make its secondary particle size will be much large.
Hydrosynthetic photocatalyst is the nano titanium dioxide with Anatase structure synthesized directly in the sol dispersing system by means of advanced chemical hydrosynthesis technology. Generally speaking, hydrosynthetic manufacture technology can produce more stable photocatalyst of quanta level with smaller particle size. The synthesis, crystallization and dispersion of nano photocatalyst are processed in the liquid, which makes the product superior to the traditional ones. The hydrosynthetic technology is a new advanced manufacture technology of photocatalyst, which provides excellent quality and property to the product. At present, most photocatalyst sol with high quality and low reunited index is made by hydrosynthetic technology.

Photocatalyst Manufacturing Technology Compare

Technology

Hydrosynthesis

Powder Redispersion

Planet Ball Milling

Manufacture Method Chemical Chemical Physical Milling

Dispersion

No surface active agent

With surface active agent

With surface active agent

Primary Particle Size

1-10nm

10-100nm

80-2000nm

Crystal Structure

Fine

Fine

Bad

Reunited Index

1-10

10-100

>100

Transparency Good No No

Sol Stability

Excellent

Good

Deposition

Photocatalytic Performance Excellent Good Normal

When photocatalyst titanium dioxide (TiO2) absorbs Ultraviolet (UV)* radiation from sunlight or illuminated light source (fluorescent lamps), it will produce pairs of electrons and holes.
The electron of the valence band of titanium dioxide becomes excited when illuminated by light. The excess energy of this excited electron promoted the electron to the conduction band of titanium dioxide therefore creating the negative-electron (e-) and positive-hole (h+) pair. This stage is referred as the semiconductor’s ‘photo-excitation’ state. The energy difference between the valence band and the conduction band is known as the ‘Band Gap’. Wavelength of the light necessary for photo-excitation is:
1240 (Planck’s constant, h) / 3.2 ev (band gap energy) = 388 nm

Fig-1 Mechanism of Photocatalysis

The positive-hole of titanium dioxide breaks apart the water molecule to form hydrogen gas and hydroxyl radical. The negative-electron reacts with oxygen molecule to form super oxide anion. This cycle continues when light is available.*Notes: Now Toyota, Misui-Chemical, TiPE develop the visible sensitive photocatalyst which can work under visible light(wavelength >380nm).

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2 Responses to “what is hydrosyntetic photocatalyst?”


  1. 1 SHRIKANT
    December 20, 2007 at 3:31 pm

    Dear sirs,

    Kindly let me know where we can purchase the nanaocrystalline TiO2 to be used in application where CO2 generation is needed.

    Indicate method of application of the material on metal surface.

    Also let us have the rate per Kg or Ton.

    with regards

    shrikant


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