Zeolite membranes on supports

Oriented two-dimensional zeolitic imidazolate framework-L membranes and their gas permeation properties

“…To estimate the degree of membrane orientation, the crystallographic preferred orientation (CPO) indexing method was used. 18,[37][38] For the ZIF-L membrane prepared at 0.5-2 h, the XRD patterns are relatively weak but match well with the simulated ZIF-L, indicating a ZIF-L layer is successfully prepared. The CPO indexes, however, are still very low for the 1 h sample (CPO 020/112 =7.2, CPO 020/004 =6.1), indicating that a large amount of crystals are still randomly oriented.…”

Secondary growth of ZIF-8 films onto copper-based foils. Insight into surface interactions

“…This effect is frequently observed in zeolite films obtained by secondary growth and could also influence their performance in processes that are sensitive to the porous topology, as adsorption or catalytic reactions [43]. The said preferential orientations can be characterized by means of a crystallographic preferential orientation index (CPO), which compares the ratio of the integrated intensities of a pair of XRD peaks of the film with the intensities of the same planes in the powder material (please see equation of CPO at the bottom of Table S1) [44]. [26].…”

Rapid fabrication of metal organic framework thin films using microwave-induced thermal deposition

“…Unambiguous evidence of the out-of-plane preferred orientation is provided by comparison of the and [2][3][4][5][6][7][8][9][10] reflections. The crystallographic preferred orientation, 28,29 CPO, for these reflections is in the range of 20-50, indicating strong orientation. We are speculating that the oriented growth might be triggered by the addition of carboxylic groups on the surface defect sites or edges of graphite flakes caused by intense microwave Joule heating in combination with preferred deposition of benzene dicarboxylic acids, the organic linker, on the aromatic carbon six rings of the graphite sheets.…”