Nanozyme Based on Porphyrinic Metal-Organic Framework for Electrocatalytic CO2 Reduction

Mimicry of natural enzyme systems is an important approach for catalyst design. To create an enzyme-inspired catalyst, it is essential to mimic both the active center and the second coordination sphere. Metal-organic frameworks (MOFs), an emerging class of porous materials, are ideal candidates for heterogeneous catalysts because their versatile building blocks confer a high level of structural tunability, and the chemical environment surrounding the active center can be controlled at the molecular level. Herein, a new 2D porphyrinic MOF, PPF-100, constructed from a nonplanar saddle-distorted porphyrin linker and a Cu paddle-wheel metal node is reported. The strategic introduction of ethyl substituents allows not only to mimic the active center and second coordination sphere but also to increase the catalytic selectivity while completely inhibiting H-2 generation in the CO2 reduction reaction

Role of Zr-6 Metal Nodes in Zr-Based Metal-Organic Frameworks for Catalytic Detoxification of Pesticides

Pesticides are chemicals widely used for agricultural industry, despite their negative impact on health and environment. Although various methods have been developed for pesticide degradation to remedy such adverse effects, conventional materials often take hours to days for complete decomposition and are difficult to recycle. Here, we demonstrate the rapid degradation of organophosphate pesticides with a Zr-based metal-organic framework (MOF), showing complete degradation within 15 min. MOFs with different active site structures (Zr node connectivity and geometry) were compared, and a porphyrin-based MOF with six-connected Zr nodes showed remarkable degradation efficiency with half-lives of a few minutes. Such a high efficiency was further confirmed in a simple flow system for several cycles. This study reveals that MOFs can be highly potent heterogeneous catalysts for organophosphate pesticide degradation, suggesting that coordination geometry of the Zr node significantly influences the catalytic activity

Impact of Zr6 Node in a Metal???Organic Framework for Adsorptive Removal of Antibiotics from Water

Quinolone-based antibiotics commonly detected in surface, ground, and drinking water are difficult to remove and therefore pose a threat as organic contaminants of aqueous environment. We performed adsorptive removal of quinolone antibiotics, nalidixic acid and ofloxacin, using a zirconium???porphyrin-based metal???organic framework (MOF), PCN-224. PCN-224 exhibits the highest adsorption capacities for both nalidixic acid and ofloxacin among those reported for MOFs to date. The accessible metal sites of Zr metal nodes are responsible for efficient adsorptive removal. This study offers a pragmatic approach to design MOFs optimized for adsorptive removal of antibiotics

Targeted Adsorptive Removal of Nonsteroidal Anti-inflammatory Drugs for Water Purification Using Nanoporous Zr-based Metal-Organic Framework Microcubes

Chemically synthesized drugs used in the industry are associated with potential environmental risks. Herein, we report the targeted adsorption of nonsteroidal anti-inflammatory drugs, with and without a carboxylic acid group, using a water-stable Zr-based porphyrinic metal???organic framework (MOF), PCN???224. Nanoporous PCN???224 contains interaction sites for drugs and thus enables the removal of organic pollutants. The removal efficiency of NPX and IBP was 96 and 94%, but PCN???224 removed only 37% of SMX from water. The apparent difference in the adsorption efficiency of PCN???224 indicates that the carboxylic acid functional groups in drugs strongly interacted with the open metal sites of the PCN???224 Zr6 node via coordination bonding, resulting in a high adsorption capacity. This discovery provided a practical approach for the selective adsorptive removal of various other drugs with carboxylate groups

Adsorptive Removal of Industrial Dye by Nanoporous Zr porphyrinic Metal-Organic Framework Microcubes

Increasing anthropogenic activities have adversely affected freshwater supply, making it an important global issue. Water resources are often contaminated by industrial dyes, which may harm both environment and human health even at low-level exposure. Herein, we report the adsorptive removal of a representative azo dye, methyl orange (MO) on PCN-224, a Zr porphyrinic metal-organic framework (MOF). Nanoporous PCN-224 has desirable structural characteristics such as an optimal pore aperture and a large pore volume optimized for trapping MO molecules, in addition to superior water stability. Significantly, through the combined investigation of experimental and theoretical studies, multiple adsorption sites such as the porphyrin linkers and Zr-6 nodes of the framework formed pi-pi interactions and hydrogen bonding with MO molecules, respectively, affording the highest adsorption capacity among the reported MOFs

Targeted Adsorptive Removal of Nonsteroidal Anti-inflammatory Drugs for Water Purification Using Nanoporous Zr-Based Metal–Organic Framework Microcubes

Chemically synthesized drugs used in the industry are associated with potential environmental risks. Herein, we report the targeted adsorption of nonsteroidal anti-inflammatory drugs, with and without a carboxylic acid group, using a water-stable Zr-based porphyrinic metal–organic framework (MOF), PCN–224. Nanoporous PCN–224 contains interaction sites for drugs and thus enables the removal of organic pollutants. The removal efficiency of NPX and IBP was 96 and 94%, but PCN–224 removed only 37% of SMX from water. The apparent difference in the adsorption efficiency of PCN–224 indicates that the carboxylic acid functional groups in drugs strongly interacted with the open metal sites of the PCN–224 Zr6 node via coordination bonding, resulting in a high adsorption capacity. This discovery provided a practical approach for the selective adsorptive removal of various other drugs with carboxylate groups

Origamic metal-organic framework toward mechanical metamaterial

Abstract Origami, known as paper folding has become a fascinating research topic recently. Origami-inspired materials often establish mechanical properties that are difficult to achieve in conventional materials. However, the materials based on origami tessellation at the molecular level have been significantly underexplored. Herein, we report a two-dimensional (2D) porphyrinic metal-organic framework (MOF), self-assembled from Zn nodes and flexible porphyrin linkers, displaying folding motions based on origami tessellation. A combined experimental and theoretical investigation demonstrated the origami mechanism of the 2D porphyrinic MOF, whereby the flexible linker acts as a pivoting point. The discovery of the 2D tessellation hidden in the 2D MOF unveils origami mechanics at the molecular level