Title | Chemistry of NOx on TiO2 surfaces studied by ambient pressure XPS: products, effect of UV irradiation, water and coadsorbed K+ |
Publication Type | Journal Article |
Year of Publication | 2013 |
Authors | Olivier Rosseler, Mohamad Sleiman, V. Nahuel Montesinos, Andrey Shavorskiy, Valerie Keller, Nicolas Keller, Marta I Litter, Hendrik Bluhm, Miquel Salmeron, Hugo Destaillats |
Journal | J. Phys. Chem. Lett. |
Volume | 4 |
Start Page | 536 |
Issue | 3 |
Pagination | 536-541 |
Date Published | 01/2013 |
Abstract | Self-cleaning surfaces containing TiO2 nanoparticles have been postulated to efficiently remove NOx from the atmosphere. However, UV irradiation of NOx adsorbed on TiO2 also was shown to form harmful gas-phase byproducts such as HONO and N2O that may limit their depolluting potential. Ambient pressure XPS was used to study surface and gas-phase species formed during adsorption of NO2 on TiO2 and subsequent UV irradiation at λ = 365 nm. It is shown here that NO3-, adsorbed on TiO2 as a byproduct of NO2 disproportionation, was quantitatively converted to surface NO2 and other reduced nitrogenated species under UV irradiation in the absence of moisture. When water vapor was present, a faster NO3- conversion occurred, leading to a net loss of surface-bound nitrogenated species. Strongly adsorbed NO3- in the vicinity of coadsorbed K+ cations was stable under UV light, leading to an efficient capture of nitrogenated compounds. |
DOI | 10.1021/jz302119g |