Scientists at Cornell Are Unraveling Titanium Dioxide’s Self-Cleaning Ability
ITHICA, NY — Titanium dioxide is one of several minerals that are self-cleaning; they use energy from the sun to convert any “schmutz” that lands on their surface to a harmless gas, which then floats away.
These minerals have been used as a coating in everything from building tiles to automotive mirrors, but the nature of their self-cleaning abilities is unclear. When the surfaces are examined in a vacuum, scientists see individual titanium atoms as expected, but when the surfaces are examined in air or solution, an unknown molecule appears to selectively attach to every other metal atom on the surface, creating a near-perfect, single-molecule-thick layer. But what are these molecules, and why don’t they bind to every metal atom?