A simple approach to reactivate silver-coated titanium dioxide photocatalyst

Deactivated silver-coated TiO2 photocatalyst can be easily reactivated by ambient light illumination. The process converts Ag0 to Ag(I) in the form of Ag2O. When the activated catalyst is used in photocatalysis, Ag(I) would be eventually reduced to Ag0 forming fresh non-aggregated silver nanoparticles on TiO2. The presence of some transitory Ag+ ions during photocatalysis can help to oxidize species adsorbed on the catalyst and regenerate a clean surface. This simple approach should be very useful for designing maintenance-free photocatalytic air purification systems.