A Crystalline Mesoporous Germanate with 48‐Ring Channels for CO₂ Separation

Abstract

One of the challenges in materials science has been to prepare crystalline inorganic compounds with mesopores. Although several design strategies have been developed to address the challenge,e xpansion of pore sizes in inorganic materials is more difficult compared to that for metal-organic frameworks.Herein, we designed an ovel mesoporous germanate PKU-17 with 3D 48 1616-ring channelsb yi ntroducing two large building units (Ge 10 and Ge 7 clusters) into the same framework. The key for this design strategy is the selection of 2-propanolamine (MIPA), whichs erves as the terminal species to promote the crystallization of Ge 7 clusters. Moreover,itisresponsible for the coexistence of Ge 10 and Ge 7 clusters.Toour knowledge,the discovery of PKU-17 sets anew recordi np ore sizes among germanates.I ti sa lso the first germanate that exhibits agood selectivity toward CO 2 over N 2 and CH 4 .

PKU‐21: A Novel Layered Germanate Built from Ge7 and Ge10 Clusters for CO2 Separation

“…SU‐64 is the only example of layered germinates, which is built from Ge 7 and Ge 9 clusters and exhibits extra‐large 18×12‐ring channels in infinite layers . This is consistent with previous observations that germanates built from different clusters may lead to more diverse germanate structures, especially those with large or extra‐large pores . Thus, to enrich the structural diversity of layered germanates, the combination of different cluster building units in one layer provides an effective way.…”

“…PKU‐21 is a novel layered germanate, it is also the second porous germanate that is built from both Ge 7 and Ge 10 clusters, following PKU‐17 . The Ge 7 cluster in PKU‐21 is 4‐connected consisting of one octahedral GeO 5 X (X=OH), two trigonal bipyramidal GeO 4 X, and four tetrahedral GeO 4 , while the Ge 10 cluster is 6‐connected and consists of four GeO 6 octahedra and six GeO 4 tetrahedra with a cube‐like Ge 4 O 4 unit at the core (Figure a).…”

About the Dominance of Mesopores in Physisorption in Amorphous Materials

“…The interactions of material moisture and the efficiency of gas separation are not fully understood [ 52 ]. Additionally, mesoporous germanate is used for CO separation and, depending on the configuration, possesses a bimodal pore size distribution [ 53 ]. Due to distinct changes in electrical impedance due to physisorption of water vapour, mesoporous materials such as metal phosphates might be used directly as humidity sensor [ 54 ].…”