CO₂ Reduction on the Pre‐reduced Mixed Ionic–Electronic Conducting Perovskites La_0.6Sr_‐0.4FeO_3‐δ and SrTi_0.7Fe_0.3O_3‐δ

Abstract

The activity of the pre‐reduced perovskites La0.6Sr0.4FeO3‐δ (LSF64) and SrTi0.7Fe0.3O3‐δ (STF73) for the CO2 reduction to CO was investigated with special focus on the reactivity of oxide‐dissolved hydrogen. This is of particular interest in hydrogen solid‐oxide electrolysis cell (H‐SOEC) technology, where proton‐conducting ceramics are used and the reaction 2e−+2H++CO2→CO+H2O is of central importance. To clarify if hydrogen dissolved in LSF64 and STF73 partakes in the CO2 reduction, temperature‐programmed reduction (TPR) in H2, followed by temperature‐programmed reoxidation (TPO) in CO2 and, moreover, temperature‐programmed desorption (TPD) of ad‐ and absorbed species were utilized. The experiments reveal that 50 mol % of the CO2 is converted by hydrogen dissolved in STF73 and reacts quantitatively. On the other hand, LSF64 converts less than 20 mol % of CO2 via dissolved hydrogen and a residual of bulk OH is still detectable after CO2‐TPO.

Carbide-Modified Pd on ZrO2 as Active Phase for CO2-Reforming of Methane—A Model Phase Boundary Approach

“…For example, support acidity vs. basicity has been proposed to influence their specific nature and distribution at the phase boundary [72]. CO 2 splitting may proceed both via reactive vacancies at the phase boundary or via intermediate vacancy-bonded oxygenates [73,74].…”

CO2 Reduction by Hydrogen Pre‐Reduced Acceptor‐Doped Ceria

“…From the CO 2 /Ar pressure ratio – which changes during the CO 2 ‐TPO run – and the chosen constant molar amount of Ar in the reactor at the start of the temperature ramp (which is calculated from the initially added Ar pressure) the mol of CO 2 in the reactor can be re‐calculated with respect to the initial conditions, thus numerically compensating the total pressure drop. The CO 2 conversion (in mol of CO 2 ) is then determined as the difference between the starting value of CO 2 and the pressure drop‐corrected amount of CO 2 remaining in the reactor at any given point during the CO 2 ‐TPO experiment . As before, the amount of consumed CO 2 was normalized to the molar sample amount.…”

Zirconium‐assistierte Aktivierung von Palladium zur Steigerung der Produktion von Synthesegas in der Trockenreformierung von Methan

“…[31] Prinzipiell kann die Kohlendioxidzersetzung direkt über reaktive oxidische Fehlstellen an der GF oder über fehlstellengebundene Oxygenate erfolgen. [32,33] Die Rolle dieser Oxygenate sollte zukünftig sowohl experimentell wie auch theoretisch noch genauer untersucht werden. Speziell in der Region oberhalb von etwa 286 eV ermçglichen die Datenqualitätu nd die Unsicherheit der Basislinienkorrektur keine eindeutige Zuordnung literaturbekannter Spezies.E bensowenig kçnnen gasphaseninduzierte Intensitätsänderungen eindeutig zugeordnet werden.…”