Highly efficient preparation of Ce0.8Sm0.2O2-δ–SrCo0.9Nb0.1O3-δ dual-phase four-channel hollow fiber membrane via one-step thermal processing approach

Abstract

Fabricating dual-phase hollow-fiber membranes via a one-step thermal processing (OSTP) approach is challenging, because of complex sintering kinetics and the subsequent impacts on membrane morphology, phase stability, and permeation properties. In this study, we have demonstrated that Ce 0.8 Sm 0.2 O 2-δ -SrCo 0.9 Nb 0.1 O 3-δ (SDC-SCN) four-channel hollow fiber membrane can be manufactured via a single high-temperature sintering process, by using metal oxides and carbonates directly as membrane materials (sources of metal ions). It has been found that use of a low ramping rate reduces grain sizes, increases grain and forming cobalt oxide nanoparticles, a key step to promoting surface exchange process followed by enhancing oxygen permeation. While the grain boundary interface region can be limited to approximately 20-30 nm. At 1173 K oxygen permeation of the SDC-SCN four-channel hollow fiber membrane was measured at approximately 1.2 mL•cm -2 •min -1 using helium as the sweep gas. Meanwhile, the dual-phase membrane shows a good tolerance to carbon dioxide, with the oxygen permeation flux fully recovered after long-term exposure to carbon dioxide (more than 100 h). This will enable further application of the OSTP approach for preparing dual-phase multi-channel hollow fiber membranes for applications of oxyfuel combustion, catalytic membrane reactors and carbon dioxide capture.

One‐step thermal processing of BaCe0.8Y0.2O3−δ hydrogen permeable multichannel hollow fiber membrane

“…With the sintering temperature was increased from 1400 to 1500 C, it can be observed that the porosity of the BCYC0 hollow fiber membrane decreases 3C,D, all the channels were complete and crack-free. White dots which were commonly observed in hollow fibers fabricated via the OSTP, [29][30][31] were observed on the inner surface of the hollow fiber. The preparation of hollow fiber membranes via the OSTP involved organic combustion and perovskite oxide synthesis, which requires the participation of oxygen.…”

“…The perovskite hollow fibers were obtained via a single‐step thermal processing, which accomplishes the in situ conversion of the raw chemicals into perovskite oxides. The OSTP approach was expected to avoid grain overgrowth and reduce the densification temperature 31 …”

“…The 7-channel configuration demonstrated an excellent compromise between flux, mechanical strength, and packing density. 29,32 In the previous OSTP studies, [29][30][31] the low melting point Co 2 O 3 in the membrane precursor was expected to facilitate the densification, therefore the effects of Co 2 O 3 on the densification temperature, microstructure, phase structure, and mechanical strength of the BCY membrane were investigated. Herein, the densification temperature is significantly reduced without hindering the stability of the material in hydrogen.…”

“…The OSTP approach was expected to avoid grain overgrowth and reduce the densification temperature. 31 In this work, we fabricated a BCY 7-channel hollow fiber membrane for hydrogen separation via the OSTP approach. The 7-channel configuration demonstrated an excellent compromise between flux, mechanical strength, and packing density.…”

Effects of Bi Substitution on the Cobalt-Free 60wt.%Ce0.9Pr0.1O2−δ-40wt.%Pr0.6Sr0.4Fe1−xBixO3−δ Oxygen Transport Membranes

“…However, for the perovskite phase, the grain boundary with higher energy often leads to phase transition and weakens the stability. Zhang group [42] and Yang group [43] added nanoparticles to the grain boundary to restrain the phase transition and prepared stable dual-phase Ce 0.8 Sm 0.2 O 2−δ -SrCo 0.9 Nb 0.1 O 3−δ and Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ OTM, respectively. For our OTMs, there are no similar structures in the grain boundary.…”