Valokatalyyttinä

Valokatalyyttinä refers to the role of a substance as a photocatalyst. A photocatalyst is a material that absorbs light energy and then uses that energy to drive a chemical reaction. This process typically involves the generation of electron-hole pairs within the photocatalyst material upon light absorption. These charge carriers then migrate to the surface of the catalyst, where they can initiate redox (reduction-oxidation) reactions with adsorbed molecules.

The most well-known and widely studied photocatalyst is titanium dioxide (TiO2). When illuminated by ultraviolet (UV) light, TiO2 becomes activated and can facilitate various chemical transformations. This includes the degradation of organic pollutants in water and air, the sterilization of surfaces by killing bacteria and viruses, and even the generation of hydrogen fuel from water.

The effectiveness of a photocatalyst depends on several factors, including its band gap energy (which determines the wavelengths of light it can absorb), surface area, crystallinity, and the presence of defects. Researchers are continuously developing new photocatalytic materials with improved efficiency and visible-light activity, which is crucial for practical applications, as visible light constitutes a larger portion of the solar spectrum. Applications of photocatalysis are diverse, ranging from environmental remediation and renewable energy production to self-cleaning surfaces and medical treatments.