Chemistry of NOx on TiO2 surfaces studied by ambient pressure XPS: Products, effect of UV irradiation, water, and coadsorbed K +
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 pressu...
| Authors: | , , , , , , , , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2013 |
| Country: | Argentina |
| Institution: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repository: | CONICET Digital (CONICET) |
| Language: | English |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/77866 |
| Online Access: | http://hdl.handle.net/11336/77866 |
| Access Level: | Open access |
| Keyword: | APXPS DENOX DEPOLLUTION HONO RENOXIFICATION https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Summary: | 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 NO 3 - 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. © 2013 American Chemical Society. |
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