Phase stability and oxygen storage capacity of PrBaMn2O6–

Insights into the Redox Behavior of Pr0.5Ba0.5MnO3−δ-Derived Perovskites for CO2 Valorization Technologies

“…The oxidation to Mn 4+ is kinetically favored by the high temperature and by the enlarged lattice of r -PBM, through which oxygen can easily migrate. , Moreover, in manganite perovskites, the reduction of Mn 4+ to Mn 3+ is typically observed in this temperature range . The second peak, at a higher temperature (420 °C), could instead be explained by a substantial anticipation of the reduction of Mn 3+ owing to the higher mobility of oxygen in the layered structure of o -PBM . The second reduction step proceeds until the equilibrium ratio between Mn 3+ , Mn 2+ , and oxygen vacancies is reached, at approximately 500 °C.…”

“…It has been recently reported that the structural changes described above bring about peculiar redox properties in PBM phases. To investigate this in more detail, reactive hot-chamber XRD and TPR results (Figure ) were combined to gain insights into the correlation between the structural evolution and the redox behavior in PBM perovskites.…”

“…The quantitative estimations obtained from TPR and TGA analyses allow us to draw some conclusions on the mixed ionic and electronic conductivity of PBM layered perovskites: The low oxygen substoichiometry of r -PBM suggests that this phase has a high concentration of oxygen vacancies in the lattice, through which O 2– anions could migrate, and therefore a high ionic conductivity. The copresence of Mn­(III) and Mn­(II) in both r -PBM and o -PBM structures should have a beneficial effect on their electronic conduction since the transport of e – through the perovskite , is due to the coupling of different oxidation states of B-site cations. The reoxidation of r -PBM does not compromise the high number of redox couples in o -PBM, permitting appropriate electronic conductivity also in oxidative conditions. , …”

“…Most of the studies on this material have been focused on the relationship between the formation of the layered structure and the exsolution process both in SOFC applications ,, and in catalysis. − Only few studies discussed the oxygen storage capacity of a layered structure, , while no detailed studies have been published on the redox processes involved in the formation and stabilization of the layered structure, at least to the best of the authors’ knowledge. In a previous study, we demonstrated that the redox behavior of PBM oxides is correlated to the structural changes that they undergo during thermal reduction.…”

A Novel, Simple and Highly Efficient Route to Obtain PrBaMn2O5+δ Double Perovskite: Mechanochemical Synthesis

“…In this sense, PBMO has shown almost complete reversibility between the fully-reduced (δ~0) and fully-oxidized (δ~1) phases at relatively low temperatures (200-500 • C) when the oxygen partial pressure is alternated between reducing and oxidizing conditions [21,22]. Moreover, it has also been proven to withstand redox cycles at higher temperatures (up to 950 • C) with only a small decrease in the maximum oxygen storage capacity [23]. These features are due to the high order degree in A-sites, which provides thermal and chemical stability under operating conditions, and the ability of the transition metal cation to accommodate different valence states (Mn 4+ /Mn 3+ /Mn 2+ ), which favor the intake and release of oxygen within the vacancy rich Pr A-site layer during the redox processes.…”