A new CO₂-resistant Ruddlesden–Popper oxide with superior oxygen transport: A-site deficient (Pr_0.9La_0.1)_1.9(Ni_0.74Cu_0.21Ga_0.05)O_4+δ

Abstract

A-site deficient (Pr 0.9 La 0.1 ) 1.9 Ni 0.74 Cu 0.21 Ga 0.05 O 4+d ((PL) 1.9 NCG), with the K 2 NiF 4 structure, is found to exhibit higher oxygen transport rates compared with its cation-stoichiometric parent phase. A stable oxygen permeation flux of 4.6 Â 10 À7 mol cm À2 s À1 at 900 C at a membrane thickness of 0.6 mm is measured, using either helium or pure CO 2 as sweep gas at a flow rate of 30 mL min À1 . The oxygen flux is more than two times higher than that observed through A-site stoichiometric (PL) 2.0 NCG membranes operated under similar conditions. The high oxygen transport rates found for (PL) 1.9 NCG are attributed to highly mobile oxygen vacancies, compensating A-site deficiency. The high stability against carbonation gives (PL) 1.9 NCG potential for use, e.g., as a membrane in oxy-fuel combustion processes with CO 2 capture.

Gas Humidification Impact on the Properties and Performance of Perovskite‐Type Functional Materials in Proton‐Conducting Solid Oxide Cells

“…Along with materials with the perovskite‐related structures, the complex oxides belonging to the Ruddlesden‐Popper phases are also considered as attractive electrodes for protonic‐conducting SOCs. For example, the Ln 2 NiO 4+δ ‐based materials (Ln = La, Pr, Nd) exhibit hydration capability, high chemical stability against the hydroxide and carbonate formation due to the absence (or reduced amount) of alkaline‐earth elements, quite low TEC values close to those of electrolytes, no meaningful pO 2 ‐induced chemical expansion, high electrical conductivity, and excellent electrochemical activity as a result of both high oxygen diffusion coefficients and surface exchange constants …”

Mixed Oxygen Ionic and Electronic Conducting Membrane Reactors for Pure Chemicals Production

“…However, their permeability cannot meet the requirement for economic applications, which need an oxygen permeation flux of at least 1 mL min -1 cm -2 [21]. To improve the oxygen permeation performance, several strategies were applied, such as the introduction of A-site deficiencies [22,23], anion doping [24,25], surface modification [26,27], and optimizing preparation procedures [32]. For example, Xue et al [28] first used anion doping strategy to develop a (Pr 0.9 La 0.1 ) 2.0 (Ni 0.74 Cu 0.21 Ga 0.05 )O 4+δ Cl 0.1 ((PL) 2.0 NCGCl 0.1 ) membrane, which showed a stable oxygen flux of 1.1 mL min -1 cm -2 at 975 °C.…”

“…Therefore, the dual-phase composites composed of oxygen ionic conductive phase and electron conductive phase have attracted widespread attention, as shown in Fig. 2 [25,29]. In general, fluorite oxides are used as oxygen ionic conducting phases due to their great oxygen ionic conductivity, excellent stability and mechanical strength [30].…”

Mixed matrix membranes containing well-designed composite microcapsules for CO2 separation

“…The regular silica particles were prepared by Stöber method [29]. And hollow particles were synthesized via a modified method based upon the previously reported procedure [28].…”