Fe‐O Clusters Anchored on Nodes of Metal–Organic Frameworks for Direct Methane Oxidation

Abstract

Direct methane oxidation into value‐added organic oxygenates with high productivity under mild condition remains a great challenge. We show Fe‐O clusters on nodes of metal–organic frameworks (MOFs) with tunable electronic state for direct methane oxidation into C1 organic oxygenates at 50 °C. The Fe‐O clusters are grafted onto inorganic Zr6 nodes of UiO‐66, while the organic terephthalic acid (H2BDC) ligands of UiO‐66 are partially substituted with monocarboxylic modulators of acetic acid (AA) or trifluoroacetic acid (TFA). Experiments and theoretical calculation disclose that the TFA group coordinated with Zr6 node of UiO‐66 enhances the oxidation state of adjacent Fe‐O cluster due to its electron‐withdrawing ability, promotes the activation of C−H bond of methane, and increases its selective conversion, thus leading to the extraordinarily high C1 oxygenate yield of 4799 μmol gcat−1 h−1 with 97.9 % selectivity, circa 8 times higher than those modulated with AA.

Heterometallic and Hydrophobic Metal–Organic Frameworks as Durable Photocatalysts for Boosting Hydrogen Peroxide Production in a Two-Phase System

“…As shown in Figure 2a, two peaks at around 710.9 and 724.3 eV are attributed to Fe 2p 3/2 and 2p 1/2 , respectively, confirming the Fe 3+ -doping in Fe-Zr-MOF and OPA/Fe-Zr-MOF according to the previous reports. 16,26,34 In addition, the corresponding peak intensities of Fe 3+ species are more weakened in the hydrophobic OPA/Fe-Zr-MOF. This could be due to the modification of the surface and the interior of MOFs by OPA, affecting the collection of kinetic energy and the number of electrons that are excited by X-rays and thus resulting in weaker XPS signals.…”

“…2,10,14,15 To be specific, the metal nodes of MOFs are often coordinated with −OH and −OH 2 groups that could further act as the connecting sites for active components, offering many opportunities for precise design of the catalyst at the molecular level. 16,17 MOFs are effective (photo)catalysts for fine chemical production (organic transformations), 18 (selective oxidation of 5-hydroxymethylfurfural to 2,5furandicarboxylic acid), 19 and solar-to-chemical energy conversion (H 2 production). 11 Thus, it is one of the potential candidates for photocatalytic H 2 O 2 production.…”

“…Metal–organic frameworks (MOFs), a class of materials formed by the connection of metal clusters with organic ligands, − have been employed in various fields of application such as sensors, gas separation and storage, and catalysis because of their intriguing characteristics, including large surface areas, well-defined metal nodes, adjustable chemical composition, rich functionality, etc. ,,, To be specific, the metal nodes of MOFs are often coordinated with −OH and −OH 2 groups that could further act as the connecting sites for active components, offering many opportunities for precise design of the catalyst at the molecular level. , MOFs are effective (photo)­catalysts for fine chemical production (organic transformations), biomass conversion (selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid), and solar-to-chemical energy conversion (H 2 production) . Thus, it is one of the potential candidates for photocatalytic H 2 O 2 production.…”

Engineering Nanoscale Metal‐Organic Frameworks for Heterogeneous Catalysis

“…Such exposed metal sites would interact with organic substrates inside the MOFs pores for proceeding catalytic activation. [ 86–89 ] The regular arrangement and tunable chemical environment of the metal centers endow MOFs with regioselectivity and shape‐/size‐selectivity.…”

High‐Performance Capacitive Deionization and Killing Microorganism in Surface‐Water by ZIF‐9 Derived Carbon Composites

“…Metal-organic frameworks (MOFs) are a new class of porous materials that have gained extensive attention for use in electrochemical applications owing to their high specific surface area, [1,2] rich pore structure, and metal-organic species. [3,4] Based on these characteristics, MOFs are considered to be suitable templates or precursors for the preparation of nanostructured metals or metal oxide/carbon composite derivatives. [5,6] Furthermore, most MOFs can be directly pyrolyzed to obtain carbon-based materials without additional carbon sources.…”