A Mixed Ionic and Electronic Conducting Dual‐Phase Membrane with High Oxygen Permeability

Abstract

To combine good chemical stability and high oxygen permeability, a mixed ionic-electronic conducting (MIEC) 75 wt% Ce(0.85)Gd(0.1)Cu(0.05)O(2-δ)-25 wt% La(0.6)Ca(0.4)FeO(3-δ)(CGCO-LCF) dual-phase membrane based on a MIEC-MIEC composite has been developed. Copper doping into Ce(0.9)Gd(0.1)O(2-δ) (CGO) oxide enhances both ionic and electronic conductivity, which then leads to a change from ionic conduction to mixed conduction at elevated temperatures. For the first time we demonstrate that an intergranular film with 2-10 nm thickness containing Ce, Ca, Gd, La, and Fe has been formed between the CGCO grains in the CGCO-LCF one-pot dual-phase membrane. A high oxygen permeation flux of 0.70 mL min(-1) cm(-2) is obtained by the CGCO-LCF one-pot dual-phase membrane with 0.5 mm thickness at 950 °C using pure CO2 as the sweep gas, and the membrane shows excellent stability in the presence of CO2 even at lower temperatures (800 °C) during long-term operation.

Dual‐Phase Oxygen Transport Membranes for Stable Operation in Environments Containing Carbon Dioxide and Sulfur Dioxide

“…Recent works on spinel-fluorite, [21][22][23][24] perovskite-fluorite, [25][26][27] and doped ZnO with fluorite [28] composite systemse xhibited material stability and promisingO 2 permeation under oxyfuel-like conditions. Gathering all the key features in one single materiali savery challenging issue.…”

Substantial Oxygen Flux in Dual-Phase Membrane of Ceria and Pure Electronic Conductor by Tailoring the Surface

“…Recently, dualphase membranes that consist of an electrolyte oxide and a perovskite material have been developed to overcome these shortcomings while maintaining a high permeability to oxygen. [9][10][11][12][13][14] Dual-phase membranes whose electronic conductor phase has a high ionic conductivity, (Ba,Sr)(Co,Fe)O 3-δ for example, 15 typically exhibit high oxygen permeability. However, the applicability of this type of membrane is questionable due to the chemical and mechanical instability of the electronic conductor under operating conditions.…”

A Highly Efficient Sandwich‐Like Symmetrical Dual‐Phase Oxygen‐Transporting Membrane Reactor for Hydrogen Production by Water Splitting

“…[10] Thus,a nM IEC-IC composite dualphase membrane is believed to be aprospective candidate for application in chemical reactors ( Figure 1). [11] To date,t remendous efforts have been made to improve the oxygen permeability by designing supported/thin membranes and modifying their surfaces. [12] Herein, we present adual-phase OTM reactor with asandwich-like symmetrical configuration, whereby two porous backbones built up on both side of the dense functional layer may alleviate the performance losses caused by slow surface-reaction kinetics ( Figure 1a).…”

“…However,c heap Ni-based catalysts are prone to deactivation as ar esult of coke deposition (that is,c arbon buildup) once pure methane has been used as the feedstock, similar to the effect observed in industrial processes for methane reforming. [11] To date,t remendous efforts have been made to improve the oxygen permeability by designing supported/thin membranes and modifying their surfaces. To maximize the function of the OTM, it is crucial to balance the high chemical stability and the practical oxygen permeability.W henc obalt/copper-containing perovskite oxides (for example,Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-d )are employed as membrane materials,t he performance of the reactor may gradually degrade with time because of the easily reducible active cations.…”