What is photocatalytic activity of TiO2?
The photocatalytic activity of TiO2 nanoparticle has pH-sensitive. The photocatalytic activity of TiO2 nanoparticle in acid condition (pH 4.1) is 40%, in neutral condition (pH 7.0) is 90%, and in base condition (pH 9.7) is 97%.
What is the photocatalytic activity?
Photocatalytic activity is a commonly investigated function of semiconductor nanoparticles. One of the most studied forms of photocatalyst nanoparticles is titanium dioxide (TiO2). TiO2 nanoparticles have a broad spectrum of activity, including against both Gram-negative and Gram-positive bacteria.
How is photocatalytic activity measured?
Throughout the measurement, the colour concentration of the solution is measured by UV-vis spectroscopy. For the determination of the photocatalytic activity, the adsorption is measured. The same surface, without UV irradiation, serves as reference.
What is photocatalysis with example?
A photocatalyst is a material which absorbs light to bring it to higher energy level and provides such energy to a reacting substance to make a chemical reaction occur. From: Bioscience and Bioengineering of Titanium Materials (Second Edition), 2013.
What is photocatalyst technology?
A photocatalyst is a substance that mediates a chemical reaction on its surface when activated by light. In both PECO and PCO air purifiers, this chemical reaction is employed to break down pollutants.
What is photocatalyst filter?
In a photocatalytic filter, ultraviolet light acts as the prime ingredient to clean the air of impurities with the help of a catalyst, in this case titanium dioxide. Photocatalytic filter does not trap the pollutants in their original form.
What is a photocatalytic process?
Photocatalysis is a process in which light energy is used to drive pairs of chemical reactions. Through the absorption of light, an excited electron/hole pair is produced.
What is PCO system?
Photocatalytic Oxidation (PCO) is a very powerful air purification technology and has the ability to destroy particles as small as 0.001 microns (nanometer) whereas HEPA filters can only filter particles as small as 0.3 microns.
Why is anatase a better photocatalyst than rutile?
For anatase the activity increases for films up to ~5 nm thick, while rutile films reach their maximum activity for ~2.5 nm films already. This shows that charge carriers excited deeper in the bulk contribute to surface reactions in anatase than in rutile.
Does the H2 thermal treatment enhance the photocatalytic activity of TiO2?
To confirm the enhancement of the photocatalytic activity of TiO 2 by the H 2 thermal treatment in general, one set of tests was conducted to photodegrade phenol in aqueous suspensions containing either the TiO 2 sample treated at 550–560 °C or the conventional TiO 2 sample without H 2 treatment. The experimental results are shown in Fig. 9.
How can I increase the photoactivity of TiO2 pigments?
In the meantime, the photoactivity of the TiO 2 pigment can be enhanced by this reduction reaction in a H 2 atmosphere at a thermal condition ( Heller et al., 1987 ).
What is the photocatalytic degradation of an organic dye?
The photocatalytic degradation of an organic dye, acid blue 9, in an aqueous solution containing titanium dioxide, is followed over time by means of UV–Vis spectrophotometry. Dye solutions containing pigments with high photocatalytic activity lose their color within several hours of UVA exposure.
Does Langmuir–Hinshelwood kinetic expression explain photocatalytic degradation of organic contaminants over illuminated TiO2?
Several studies ( Pruden and Ollis, 1983; Ollis et al., 1984; Matthews, 1988) indicated that the rate of photocatalytic degradation of various organic contaminants over illuminated TiO 2 could be explained with the Langmuir–Hinshelwood (L–H) kinetic expression.