UiTM researchers have developed a modified photocatalyst which is economical and effective at transforming organic pollutants into harmless end products.
Titanium dioxide (TiO2) is the most commonly used photocatalyst in many environmental applications but it can be used only under UV light owing to its high band gap energy (3.2 eV). UV light being energy intensive, it makes the photocatalytic degradation process very expensive.
In solar light spectrum, UV light exists only within 3-5% compared to visible light (45%). Therefore, for practical application, it is highly desirable to develop TiO2 photocatalyst which can effectively degrade the pollutants under visible light irradiation.
Various techniques proposed in the literature to extend the absorption wavelength from UV to visible light region include semiconductor coupling, metal doping, dye sensitising and doping with nonmetal elements.
The most feasible method to modify the structure of photocatalyst is by doping with nonmetal, since it narrows down the band gap besides being stable, inexpensive and non photo corrosive. Doping with nitrogen attracted huge attention due to its high visible light active photocatalytic efficiency. Other nonmetal elements commonly used as dopants include iodine, carbon, sulphur and boron.
Read more at: Phys.org