The interaction of CO₂ and CO with Fe‐doped SrTiO₃(100) surfaces

Abstract

The interaction of CO 2 and CO with 0.013 at.% Fe-doped SrTiO 3 (100) was investigated in situ with Metastable Induced Electron Spectroscopy (MIES) and XPS at room temperature. To clear up the influence of surface defects, cleaned and sputtered SrTiO 3 surfaces were investigated. Sputtering results in the breaking of Ti-O bonds in the surface and the formation of oxygen-related defects as well as reduced titanium on the surface.Cleaned SrTiO 3 surfaces do neither interact with CO 2 nor with CO. Sputtered surfaces show a CO 2− 3 formation during CO 2 exposure and -to a lesser extent -during CO exposure. The CO 2− 3 groups can be detected very well with MIES because of its extreme surface sensitivity. With XPS, the characteristic carbonate peak shift of the C 1s orbitals can be detected.

Hydrogen‐assisted Carbon Dioxide Thermochemical Reduction on La0.9Ca0.1FeO3−δ Membranes: A Kinetics Study

“…Here, Ti 00 Ti and Ti X Ti are titaniumc ations with + 2a nd + 4v alences, respectively.Y et the stabilityo ft he carbonate depends on the temperature and CO 2 partial pressure, and carbonates can decompose into oxidesa nd CO 2 at lower CO 2 concentrations and highertemperatures. [38,40] Similar mechanisms have been expected for the Ca-doped LaFeO 3 as an acceptor-doped perovskite. Herein,t he LCF-91 membranes operating in the temperature range of 850-1030 8Ca re examined.…”

“…Here, and are titanium cations with +2 and +4 valences, respectively. Yet the stability of the carbonate depends on the temperature and CO 2 partial pressure, and carbonates can decompose into oxides and CO 2 at lower CO 2 concentrations and higher temperatures …”

“…For the carbonate pathway,e xperiments show that carbonates are formedo nv arious perovskites, such as Fe-doped [38] or Rh-doped [39] SrTiO 3 surfaces, SrCo 0.8 Fe 0.2 O 3Àd [40] and BaCo 0.4 Fe 0.6Àx Zr x O 3Àd [41] when these materials are exposed to CO 2 .P ossible reactions have been proposed on an Fe-doped SrTiO 3 surfacefor the carbonatepathway: [38]…”

Recent Progress in Photocatalytic CO2 Reduction Over Perovskite Oxides

“…Thus, SrTiO 3 can be viewed as a sequence of alternating charge neutral SrO and TiO 2 sheets. Pristine SrTiO 3 generally shows poor CO 2 adsorption ability, though this can be improved enormously if surface oxygen vacancies and coordinatively unsaturated metal centers can be introduced into the alternating SrO and TiO 2 sheets . Strategies for improving SrTiO 3 performance including doping with active metal cations, introducing surface defects, adding metal co‐catalysts or forming heterojunctions with other semiconductors.…”

Investigation of surface Sr segregation in model thin film solid oxidefuel cell perovskite electrodes

“…4). It is reasonable to exclude a role for the reaction products on the impedance studies given that these speices are known to be removed from the SrTiO 3 surface upon heat-treatment, [18][19][20] under conditions comparable to those found under SOFC operation. One can also exclude the possibility of finding metallic Sr at the surface of the STF films, consistent with recent theoretical calculations reporting that pure Sr is highly unlikely on SrTiO 3 surfaces.…”