Post‐Synthetic Modification of ZIF‐8 Crystals and Films through UV Light Photoirradiation: Impact on the Physicochemical Behavior of the MOF

Abstract

The physicochemical modification of Metal‐Organic Frameworks (MOFs) is a current challenge in the search to improve their performance in different technological applications. In this work we analyze the post‐synthetic modification of ZIF‐8 crystals and films through a simple and clean treatment that involves the exposure to a UV lamp under environmental conditions. It is demonstrated that a short treatment alters the MOF structure and chemistry, providing a modified ZIF‐8 due to partial disconnections of its structure which increase the amount of terminal surface species such as Zn−OH and −C=N‐H, but without compromising the overall MOF structure, specific surface area or thermal stability. Additionally, it leads to changes in several properties of the ZIF‐8, such as its capacity to accumulate charge through pseudocapacitive processes, its interaction with nitric oxide and its light absorption behavior. This strategy of modifying ZIF‐8 without the use of chemicals through a gentle disconnection of its own structure could open new perspectives of post‐functionalization of crystals and films of ZIF‐8 to be used in a wide range of applications.

Air‐Steam Etched Construction of Hierarchically Porous Metal‐Organic Frameworks

“…In particular, intensity invariance of –CH 3 mode at 1384 cm –1 , C=N mode at 1584 cm –1 , CH bending of imidazolate structure at 1145 cm –1 , and Zn—N peak at 420—422 cm –1 , rules out the breakage mIm linker in etched ZIF‐8 samples. [ 37‐40 ] Besides, 1 H NMR spectra (Figure S6) of all H‐ZIF‐8 are very similar to that of pristine ZIF‐8, further indicating the retention of the original structure of imidazolate linker after etching treatment.…”

Bio‐Templated Chiral Zeolitic Imidazolate Framework for Enantioselective Chemoresistive Sensing

“…Additionally, there are no characteristic CNC peaks in the templated ZIF, showing the successful complete removal of the CNC component (Figure S6) [41,42] . X‐ray photoelectron spectroscopy (XPS) confirms that the carbon/nitrogen atomic percentage ratio of the extracted, templated ZIF is identical to freely grown ZIF‐8 (Figures S7 and S8) [43,44,45] . Furthermore, EDX mapping of the templated ZIF demonstrates a homogeneous distribution of zinc and nitrogen atoms across the specimen (Figures 2g and 2h).…”

“…[41,42] X-ray photoelectron spectroscopy (XPS) confirms that the carbon/nitrogen atomic percentage ratio of the extracted, templated ZIF is identical to freely grown ZIF-8 (Figures S7 and S8). [43,44,45] Furthermore, EDX mapping of the templated ZIF demonstrates a homogeneous distribution of zinc and nitrogen atoms across the specimen (Figures 2g and 2h). Overall, these chemical compositional analyses confirm the removal of CNC from the ZIF-CNC composite and, thus, the formation of pure templated ZIF material free of traces of the original bio-template.…”

Ordered Macro–Microporous ZIF-8 with Different Macropore Sizes and Their Stable Derivatives for Lipase Immobilization in Biodiesel Production

“…More and more studies have been focused on the stabilization of MOFs to meet the requirements of practical applications. Recently, more and more strategies for enhancing the stability of MOFs have been reported, endowed by the high tunability and designability of them, such as post−synthetic exchange and modification, , surface hydrophobic modification, ,, and formation of composite, etc . Based on these reports, experimental efforts were made in this study to achieve the stabilization of ZIF-8 as carrier materials for lipase immobilization in biodiesel production as well as other complex systems.…”