Novel cobalt-free CO2-tolerant dual-phase membranes of Ce0.8Sm0.2O2−–Ba0.95La0.05Fe1−Zr O3− for oxygen separation

Abstract

a b s t r a c tA novel series of cobalt-free dense oxygen-permeable dual-phase membranes with a composition of 60 wt% Ce 0.8 Sm 0.2 O 2 À δ and 40 wt% Ba 0.95 La 0.05 Fe 1 À x Zr x O 3 À δ (SDC-BLFZ, x ¼0-0.20) are successfully developed and systematically evaluated as potential oxygen transport membranes for oxy-fuel combustion. The effects of substituting zirconium for iron on the structural characteristics, oxygen permeability, and CO 2 resistance of these membranes are studied. Experimental results show that appropriate doping of zirconium slightly decreases the oxygen permeability of the SDC-BLFZ membranes under helium but significantly enhances the structural stability and CO 2 tolerance. For the sample with x ¼0.15, a stable oxygen permeation flux of 0.24 ml min À 1 cm À 2 was achieved at 925 1C for a 1.0 mm thick membrane with CO 2 as the sweep gas for more than 80 h. This flux value is only 19% lower than that under an air/He gradient, which is much better than that obtained with most alkaline-metalcontaining composite dual-phase membranes. The enhanced CO 2 tolerance of the Zr-doped SDC-BLFZ membranes is attributed to the declining basicity of BLFZ induced by the substitution of Fe by Zr, as revealed by X-ray photoelectron spectroscopy (XPS). The stable oxygen permeability of the SDC-BLFZ membranes under CO 2 demonstrates the potential application of SDC-BLFZ in oxy-fuel combustion technology.

Effects of B‐site doped elements in the electronic‐conducting perovskite phase on the property of dual‐phase membranes

“…As listed in Figure , the O 1s binding energies of BLFM 0.10 oxides with the different doped ions follow the order: BLFSc 0.10 (280.34 eV)>BLFNb 0.10 (280.29 eV)>BLFZr 0.10 (280.24 eV)>BLFY 0.10 (280.11 eV)>BLF (280.04 eV)>BLFZn 0.10 (280.01 eV). For the same oxide system, the higher O 1s binding energy, the weaker ability of donating electron pair, the lower the basicity of the metal oxide . Therefore, for the same system of BLFM 0.10 oxides, the O 1s binding energy reflects the relative height of the basicity.…”

“…Therefore, the research on the perovskite phase of dual‐phase membranes has great significance. Ce 0.8 Gd 0.2 O 2−δ ‐Ba 0.95 La 0.05 FeO 3−δ and Ce 0.8 Sm 0.2 O 2−δ ‐Ba 0.95 La 0.05 FeO 3−δ dual‐phase membranes showed poor oxygen permeation stability under a pure CO 2 atmosphere, but their stabilities were effectively enhanced by introducing Nb and Zr on the B‐site of the perovskite phase …”

Process intensification in the catalytic conversion of natural gas to fuels and chemicals

“…Dual phase membranes provide a means to incorporate highly stable ceramics and also deliver good oxygen fluxes [215][216][217][218][219] . As illustrated in Fig.…”

High-flux dual-phase percolation membrane for oxygen separation

“…Besides, the oxygen permeability of a fluorite-perovskite OTM usually depends on the transport rate of oxygen ions due to oxygen ions transport much slower than electrons [40,41]. Under the premise of two phases form respectively interpenetrating continuous network, it is reasonable to maximize the content of fluorite phase when designing a fluorite-perovskite OTM.…”