In 1985,Matsunagaandcolleaguesobservedtheantimicrobial
activityofTiO2 [9]. Inparticular,microbialcellscouldbekilledby
the contactwithaTiO2–Pt catalystunderilluminationwithnear
UV light.WhenTiO2 is irradiatedwithphotonsofenergyequalto
or higherthanitsband-gap(3.15eVforanatase,3.05eVforrutile
crystallinephase [10]), electron–hole pairsaregenerated