Selective photocatalytic oxidation of gaseous ammonia at ppb level over Pt and F modified TiO2

Ammonia (NH3) as an important precursor to form atmospheric fine particles and secondary inorganic aerosols, should be strictly controlled. Photocatalysis has provided a facile effective way eliminate NH3 pollution under mild conditions, whereas the undesirable products, such NO, NO2 would generated during reaction mechanism remains unclear. In this study, F or Pt modified TiO2 were explored reduce formation of NOx photocatalytic oxidation low-concentration NH3, its activity, selectivity conversion systematically studied. Results indicate that surface fluorination on contribute reduction noxious NOx, especially for NO2, since achieved enhanced adsorption strong electron-trapping ability, which can retard recombination photo-generated electrons holes. addition, deposition could further extend lifetime electron-hole pairs by strongly capture electron, enhance into nitrates nitrites species. From in-situ DRIFT spectroscopy XPS results, we deduce reactive amino radical (•NH2) formed photoirradiation after Lewis acid cites. The •NH2 react with oxygen species in presence H2O, produce HNOx. By both enhancing separation efficiency pairs, modification changes pathway conversion. proposed selective may offer novel insight other metal oxide broadly employed air control indoor environments.