The basic component of titanium dioxide (TiO2) is the element titanium, which is among the ten most abundant metals in the Earth’s crust. In nature, TiO2 is present in three different crystal structures, whereby all three exhibit different physical properties that find different applications. This makes TiO2 a widely used product component that improves the texture of paints and lacquers, cosmetics, textiles, paper, plastics as well as foods. In sunscreens, nano-TiO2 has been incorporated as a so-called physical UV-filter since about 1990. The photocatalytic effect of nano-TiO2 is also exploited in a wide range of products. The high oxidation potential of nano-TiO2 coatings is used to produce self-cleaning surfaces because this property helps decompose organic pollutants and therefore also kills bacteria. In the future, the photochromic and electrochromic properties (reversible color changes due to light or electric current) will find greater use. Finally, current research is focusing on the use of nano-TiO2 in alternative energy production