Photocatalytic degradation of various organic pollutants has been proposed as a viable alternative in decontamination of waste water or drinking water. The rate of photoinduced heterogeneous reactions on semiconductor particles is usually influenced by the concentration of pollutants. Since the concentrations of the pollutants to be decomposed often lie in the ppm range or less, their low-frequent collision with TiO₂ photocatalysts makes the mineralization rate very low. In addition, the rate is also influenced by the adsorption ability of the polar surface of TiO₂. A promising way to achieve the goal could be the use of adsorbents (SiO₂, activated carbon, zeolites) as supporting materials for TiO₂. Titanium dioxide can be anchored to supports using various procedures, e.g. hydrolysis of alkoxides. Inert supports for TiO₂ loading are effective in enhancing the photodecomposition rate because they concentrate substrates around TiO₂ particles.