Mesoporous　nanocrystalline　TiO2-xNx　and　TiO　2-xNx/ZrO2　visible-light　photocatalysts　have　been　prepared　by　a　solgel　method.　The　photocatalysts　were　characterized　by　XRD,　N2　adsorption-desorption,　TEM,　XPS,　UV/Vis,　and　IR　spectroscopy.　The　photocatalytic　activity　of　the　samples　was　evaluated　by　the　decomposition　of　ethylene　in　air　under　visible　light　(λ　＞　450　nm)　illumination.　Results　revealed　that　nitrogen　was　doped　into　the　lattice　of　TiO2　by　the　thermal　treatment　of　NH3-adsorbed　TiO2　hydrous　gels,　converting　the　TiO2　into　a　visible-light　responsive　catalyst.　The　introduction　of　ZrO2　into　TiO2-xNx　considerably　inhibits　the　undesirable　crystal　growth　during　calcination.　Consequently,　the　ZrO2-modified　TiO2-xNx　displays　higher　porosity,　higher　specific　surface　area,　and　an　improved　thermal　stability　over　the　corresponding　unmodified　TiO2-xNx　samples.　©　2006　American　Chemical　Society.