Excellent and CO${}_2$${}_{0.85}$Nd${}_{0.1}$Cu${}_{0.05}$O${}_{2-\hat{I}´}$-Nd${}_x$Sr${}_{1-x}$Fe${}_{1-y}$Cu${}_y$O${}_{3-\hat{I}´}$ dual-phase oxygen transport membranes

Abstract

Oxygen transport membranes(OTMs)have provided great opportunities in the last decades but are suffering from the trade-off effect between stability and oxygen permeability. Here, we report a group of new planar dual-phase mixed ionic-electronic conducting (MIEC) OTMs consisting of CO${}_2$${}_{0.85}$Nd${}_{0.1}$Cu${}_{0.05}$O${}_2$ (CNCO) and Nd${}_x$Sr${}_{1-x}$Fe${}_{1-y}$Cu${}_y$O${}_3$(NSFCO; $x=0.4,0.6$; $y=0.05,0.1$) phases, showing excellent oxygen permeability while comparable CO${}_2$-resistant stability. The substitution of Cu as a bifunctional additive decreases the sintering temperature and enhances bulk diffusion and oxygen permeability with the co-doping of Nd.The oxygen permeation fluxes reached 2.62 and 1.52 mL min${}^{-1}$ cm${}^{-2}$ at 1000${}^{\circ }$C through the optimal 60wt%Ce0.85Nd0.1Cu0.05O2-40wt%Nd0.4Sr0.6Fe0.9Cu0.1O3 (CNCO-NSFCO41) composition with He and CO${}_2$ sweeping, respectively, higher than all reported dense dual-phase OTMs. Such excellent CO${}_2$-tolerant permeability meets the needs of potential industrial applications. Analysis with Zhu's oxygen permeation model shows lower bulk diffusion resistance of CNCO-NSFCO41 than that of reported 60wt%Ce0.85Pr0.1Cu0.05O2-40wt%Pr0.4Sr0.6Fe0.9Cu0.1O3(CPCO-PSFCO41)and more limitation by the interfacial exchange at high temperature. All the prepared OTMs also show good long-term stability over 100 hours in both atmospheres. Our results confirm the excellent oxygen permeability and stability under a high-concentration CO2 atmosphere, providing a material candidate for CO2 capture in oxyfuel combustion.

36 pages, 6 figures