Fotokatalyyttisiä

Fotokatalyyttisiä refers to processes driven by photocatalysis. Photocatalysis is a chemical reaction that is initiated or accelerated by the absorption of light. This phenomenon involves a photocatalyst, which is a substance that can absorb photons and generate reactive species, such as electron-hole pairs. These reactive species then participate in chemical transformations, often leading to the degradation of organic pollutants, water splitting for hydrogen production, or the synthesis of valuable chemicals.

A common example of a photocatalyst is titanium dioxide (TiO2). When exposed to ultraviolet (UV) light, TiO2 becomes photoactive. The absorbed photons excite electrons in the TiO2, leaving behind positively charged "holes." These electron-hole pairs can then react with adsorbed water and oxygen molecules on the surface of the TiO2 to produce highly reactive hydroxyl radicals (•OH) and superoxide radicals (O2•−). These radicals are powerful oxidizing agents that can break down a wide range of organic compounds into simpler, less harmful substances like carbon dioxide and water.

The applications of fotokatalyyttisiä processes are diverse and continue to expand. They are employed in environmental remediation for air and water purification, self-cleaning surfaces, and antimicrobial coatings. In the energy sector, photocatalysis is being explored for solar fuel generation, particularly hydrogen production from water. Furthermore, photocatalytic reactions are utilized in organic synthesis for creating complex molecules. The efficiency and effectiveness of fotokatalyyttisiä processes depend on factors such as the type of photocatalyst, light intensity and wavelength, temperature, and the concentration of reactants.