Surface-Seal Encapsulation of a Homogeneous Catalyst in a Mesoporous Metal–Organic Framework

Abstract

A rapid surface sealing strategy has been developed for the encapsulation of a homogeneous catalyst, phosphotungstic acid (PTA), in a mesoporous metal−organic framework (MOF), . This new surface polymerization method utilizes non-solvent-induced phase separation to concentrate and direct polyamine and dianhydride monomers onto MOF particle surfaces, thus realizing the formation of a sub-10 nm, uniform, and cross-linked polymer coating within a few seconds. While fully preserving the catalytic activity of the neat PTA for the catalytic decomposition of phenol, the surface-sealed PTA-MOF composite catalyst can be reused up to 10 times with no noticeable loss of activity and negligible leaching of PTA. Since this surface coating method is not limited by either the MOF or the catalyst, it will become the technique of choice for the immobilization of homogeneous catalysts in MOFs.

Tailoring defect-type and ligand-vacancies in Zr(iv) frameworks for CO2 photoreduction

“…1,2 Until now, a variety of MOFs have been reported and developed for various applications, covering drug delivery, 3,4 chemical sensing, 5,6 gas sorption/storage and catalysis. [7][8][9][10] In recent years, MOFs have been demonstrated to show potential in the photocatalytic eld, since their structural tunability allows them to exhibit catalytic activity in the photocatalytic process, enabling MOFs devoted to systematic and structural-dependent photocatalytic investigations. [11][12][13] Much effort has been made to improve the efficiency of MOF photocatalysts including structural engineering, modication and functionalization.…”

One-step rapid fabrication of MOF@polymer core–shell particles through non-solvent induced surface deposition

“…To circumvent this issue, our group recently developed a rapid surface polymerization method for the fabrication of polyimide (PI) coatings on MOF surfaces. 40 This method utilizes a non-solvent induced phase separation mechanism to direct dianhydride and diamine monomers to the MOF surface, thus achieving surface-specific polymerization. The reaction was carried out at room temperature and can be finished in less than one minute with up to 90% utilization of monomers.…”

Noncovalent Surface Modification of Metal–Organic Frameworks: Unscrambling Adsorption Properties via Isothermal Titration Calorimetry

“…3,4 They have also increasingly been used for catalysis, 5 as functionalized nodes present a stable single-or multiatom active site 6−8 that can be surrounded by other moieties via linker modification. 9 Affecting the interface between the internal surface area of the framework and the external solution or gas is a powerful way of controlling these applications by controlling access to the interior 10,11 and has been used to separate gases in MOF liquids, 12 encapsulate catalysts, 13 and prevent hydrolytic decomposition. 14,15 Most MOF modification methods utilize covalent bonds between the metal nodes and functional groups on the target molecule.…”

“…Surface modification of metal–organic frameworks (MOFs) is an important and expanding area of research. , Constructed of inorganic node units connected by organic linkers into crystalline structures, MOFs have both internal and external surface areas, making them useful for applications like gas storage or separations. , They have also increasingly been used for catalysis, as functionalized nodes present a stable single- or multiatom active site − that can be surrounded by other moieties via linker modification . Affecting the interface between the internal surface area of the framework and the external solution or gas is a powerful way of controlling these applications by controlling access to the interior , and has been used to separate gases in MOF liquids, encapsulate catalysts, and prevent hydrolytic decomposition. , …”