TiO2-based gas sensor: A possible application to SO2
2013 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, Vol. 5, no 17, 8516-8522 p.Article in journal (Refereed) Published
Fixation of SO2 molecules on anatase TiO2 surfaces with defects have been investigated by first-principles density functional theory (DFT) calculations and in situ Fourier transform infrared (FTIR) surface spectroscopy on porous TiO2 films. Intrinsic oxygen-vacancy defects, which are formed on TiO2(001) and TiO2(101) surfaces by ultraviolet (UV) light irradiation and at elevated temperatures, are found to be most effective in anchoring the SO2 gas molecules to the TiO 2 surfaces. Both TiO2(101) and TiO2(001) surfaces with oxygen vacancies are found to exhibit higher SO2 adsorption energies in the DFT calculations. The adsorption mechanism of SO 2 is explained on the basis of electronic structure, charge transfer between the molecule and the surface, and the oxidation state of the adsorbed molecule. The theoretical findings are corroborated by FTIR experiments. Moreover, the (001) surface with oxygen vacancies is found to bind SO 2 gas molecules more strongly, as compared to the (101) surface. Higher concentration of oxygen vacancies on the TiO2 surfaces is found to significantly increase the adsorption energy. The results shed new insight into the sensing properties of TiO2-based gas sensors.
Place, publisher, year, edition, pages
2013. Vol. 5, no 17, 8516-8522 p.
anatase TiO2 surfaces, gas sensors, SO2 fixation
Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-133381DOI: 10.1021/am4018835ISI: 000330017100036ScopusID: 2-s2.0-84884221035OAI: oai:DiVA.org:kth-133381DiVA: diva2:661964
FunderFormasSwedish Energy AgencyThe Wenner-Gren Foundation
QC 201311052013-11-052013-10-312014-02-17Bibliographically approved