Department of Advanced Material Engineering, Chungbuk National University , Chungdae-ro 1, Cheongju 28644, Republic of Korea.
Korea Institute of Energy Research , Separation and Conversion Materials Laboratory, 152 Gajeong-ro, Daejeon, 34129, Republic of Korea.
ACS Appl Mater Interfaces. 2017 Jun 14;9(23):19917-19924. doi: 10.1021/acsami.7b04685. Epub 2017 Jun 5.
The dual-phase membrane has received much attention as the solution to the instability of the oxygen permeation membrane. It has been reported that the oxygen flux of the dual-phase membrane is greatly enhanced by the active coating layer. However, there has been little discussion about the enhancement mechanism by surface coating in the dual-phase membrane. This study investigates the oxygen flux of the CeGdO-LaSrMnO (GDC 80 vol %/LSM 20 vol %) composite membrane depending on the oxygen partial pressure (P) to elucidate the mechanism of enhanced oxygen flux by the surface modification in the fluorite-rich phase dual-phase membrane. The oxygen permeation resistances were obtained from the oxygen flux as a function of P using the oxygen permeation model. The surface exchange coefficient (k) and the bulk diffusion coefficient (D) were calculated from these resistances. According to the calculated k and D values, we concluded that the active coating layer (LaSrCoO) significantly increased the k value of the membrane. Furthermore, the surface exchange reaction on the permeate side was more sluggish than that at the feed side under operating conditions (feed: 0.21 atm/permeate side: 4.7 × 10 atm). Therefore, the enhancement of the oxygen surface exchange kinetics at the permeate side is more important in improving the oxygen permeation flux of the thin film-based fluorite-rich dual-phase membrane. These results provide new insight about the function of the surface coating to enhance the oxygen permeation flux of the dual-phase membrane.
双相膜作为氧渗透膜不稳定的解决方案受到了广泛关注。据报道，活性涂层大大提高了双相膜的氧通量。然而，对于双相膜中表面涂层的增强机制，人们讨论得很少。本研究通过氧分压（P）来研究 CeGdO-LaSrMnO（GDC80vol%/LSM20vol%）复合膜的氧通量，以阐明富萤石相双相膜表面改性增强氧通量的机制。通过氧渗透模型，从氧通量随 P 的函数中得到氧渗透阻力。从这些阻力中计算出表面交换系数（k）和体扩散系数（D）。根据计算出的 k 和 D 值，我们得出结论，活性涂层（LaSrCoO）显著提高了膜的 k 值。此外，在操作条件下（进料侧：0.21atm/渗透侧：4.7×10atm），渗透侧的表面交换反应比进料侧更缓慢。因此，在提高基于薄膜的富萤石双相膜的氧渗透通量方面，增强氧在渗透侧的表面交换动力学更为重要。这些结果提供了关于表面涂层增强双相膜氧渗透通量的功能的新见解。
