Search

Photocatalytic hydrogen production offers an alternative pathway to establish a sustainable energy economy, utilizing the Earth's natural sunlight and water resources to address environmental concerns associated with fossil fuel combustion. While numerous photoactive materials exhibit high potential for generating hydrogen from water, the synergy achieved by combining two different materials with complementary properties in the form of heterojunctions can significantly enhance the rate of hydrogen production and quantum efficiency. Our study describes the design and generation of the metal–organic framework‐derived (MOF) metal oxide heterojunction herein referred to as RTTA, composed of RuO2/N,S‐TiO2. The RuO2/N,S‐TiO2 is generated through the pyrolysis of MOFs, Ru‐HKUST‐1, and the amino‐functionalized MIL‐125‐NH2 in the presence of thiourea. Among the various RTTA materials tested, RTTA‐1, characterized by the lowest RuO2 content, exhibited the highest hydrogen evolution rate, producing 10,761 μmol ⋅ hr−1 ⋅ g−1 of hydrogen with an apparent quantum yield of 10.0 % in pure water containing glycerol. In addition to RTTA‐1, we generated two other MOF‐derived metal oxide heterojunctions, namely ZTTA‐1 (ZnO/N,S‐TiO2) and ITTA‐1 (In2O3/N,S‐TiO2). These heterojunctions were tested for their photocatalytic activity, leading to apparent quantum yields of 0.7 % and 0.3 %, respectively. The remarkable photocatalytic activity observed in RTTA‐1 is thought to be attributed to the synergistic effects arising from the combination of metallic properties inherent in the metal oxides, complemented by the presence of suitable band alignment, porosity, and surface properties inherited from the parent MOFs. These properties enhance electron transfer and restrict hole movement. The photocatalytic efficiency of RTTA‐1 was further demonstrated in actual water samples, producing hydrogen with a rate of 8,190 μmol ⋅ hr−1 ⋅ g−1 in tap water, and 6,390 μmol ⋅ hr−1 ⋅ g−1 in river water. [ABSTRACT FROM AUTHOR]

It remains a challenge to design aqueous electrolytes to secure the complete reversibility of zinc metal anodes. The concentrated water‐in‐salt electrolytes, e.g., 30 m ZnCl2, are promising candidates to address the challenges of the Zn metal anode. However, the pure 30 m ZnCl2 electrolyte fails to deliver a smooth surface morphology and a practically relevant Coulombic efficiency. Herein, it is reported that a small concentration of vanillin, 5 mg mLwater−1, added to 30 m ZnCl2 transforms the reversibility of Zn metal anode by eliminating dendrites, lowering the Hammett acidity, and forming an effective solid electrolyte interphase. The presence of vanillin in the electrolyte enables the Zn metal anode to exhibit a high Coulombic efficiency of 99.34% at a low current density of 0.2 mA cm−2, at which the impacts of the hydrogen evolution reaction are allowed to play out. Using this new electrolyte, a full cell Zn metal battery with an anode/cathode capacity (N/P) ratio of 2:1 demonstrates no capacity fading over 800 cycles. [ABSTRACT FROM AUTHOR]

Aqueous electrolytes typically suffer from poor electrochemical stability; however, eutectic aqueous solutions—25 wt.% LiCl and 62 wt.% H3PO4—cooled to −78 °C exhibit a significantly widened stability window. Integrated experimental and simulation results reveal that, upon cooling, Li+ ions become less hydrated and pair up with Cl−, ice‐like water clusters form, and H⋅⋅⋅Cl− bonding strengthens. Surprisingly, this low‐temperature solvation structure does not strengthen water molecules' O−H bond, bucking the conventional wisdom that increasing water's stability requires stiffening the O−H covalent bond. We propose a more general mechanism for water's low temperature inertness in the electrolyte: less favorable solvation of OH− and H+, the byproducts of hydrogen and oxygen evolution reactions. To showcase this stability, we demonstrate an aqueous Li‐ion battery using LiMn2O4 cathode and CuSe anode with a high energy density of 109 Wh/kg. These results highlight the potential of aqueous batteries for polar and extraterrestrial missions. [ABSTRACT FROM AUTHOR]

Luminescent materials with tunable emission are becoming increasingly desirable as we move towards needing efficient Light Emitting Diodes (LEDs) for displays. Key to developing better displays is the advancement of strategies for rationally designing emissive materials that are tunable and efficient. We report a series of emissive metal‐organic frameworks (MOFs) generated using BUT‐10 (BUT: Beijing University of Technology) that emits green light with λmax at 525 nm. Post‐synthetic reduction of the ketone on the fluorenone ligand in BUT‐10 generates new materials, BUT‐10‐M and BUT‐10‐R. The emission for BUT‐10‐R is hypsochromically‐shifted by 113 nm. Multivariate BUT‐10‐M structures demonstrate emission with two maxima corresponding to the emission of both fluorenol and fluorenone moieties present in their structures. Our study represents a novel post‐synthetic ligand reduction strategy for producing emissive MOFs with tunable emission ranging from green, white‐blue to deep blue. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of photoactive polymeric organo‐sulfur (POS) materials. These polymers absorb light in the ultraviolet/visible and near‐infrared region of the solar spectrum, and upon irradiation, they reduce water to hydrogen (H2). The decoration of POS materials with nitrile (−CN) groups is found to be the critical factor for enhanced interactions with the co‐catalyst, Ni2P, leading to greater H2 evolution rates compared to the nitrile‐free POS material. [ABSTRACT FROM AUTHOR]

We describe the use of CO2 as a promising C1 source instead of CO in the tandem Pauson‐Khand reaction. The reaction is achieved by combining the reduction of CO2 to CO using a metal organic framework (MOF) catalyst with homogeneous rhodium catalysts for the cycloaddition step. A range of substrates were converted in moderate to good yields. [ABSTRACT FROM AUTHOR]

Methanation of carbon dioxide (CO2) is attractive within the context of a renewable energy refinery. Herein, we report an indirect methanation method that harnesses amino alcohols as relay molecules in combination with a catalyst comprising ruthenium nanoparticles (NPs) immobilized on a Lewis acidic and robust metal–organic framework (MOF). The Ru NPs are well dispersed on the surface of the MOF crystals and have a narrow size distribution. The catalyst efficiently transforms amino alcohols to oxazolidinones (upon reaction with CO2) and then to methane (upon reaction with hydrogen), simultaneously regenerating the amino alcohol relay molecule. This protocol provides a sustainable, indirect way for CO2 methanation as the process can be repeated multiple times. [ABSTRACT FROM AUTHOR]

Metal nanoparticles (NPs) are usually stabilized by a capping agent, a surfactant, or a support material, to maintain their integrity. However, these strategies can impact their intrinsic catalytic activity. Here, we demonstrate that the in‐situ formation of copper NPs (Cu0NPs) upon the reduction of the earth‐abundant Jacquesdietrichite mineral with ammonia borane (NH3BH3, AB) can provide an alternative solution for stability issues. During the formation of Cu0NPs, hydrogen gas is released from AB, and utilized for the reduction of nitroarenes to their corresponding anilines, at room temperature and under ambient pressure. After the nitroarene‐to‐aniline conversion is completed, regeneration of the mineral occurs upon the exposure of Cu0NPs to air. Thus, the hydrogenation reaction can be performed multiple times without the loss of the Cu0NPs' activity. As a proof‐of‐concept, the hydrogenation of drug molecules "flutamide" and "nimesulide" was also performed and their corresponding amino‐compounds were isolated in high selectivity and yield. [ABSTRACT FROM AUTHOR]

This work introduces a novel method of recovering bioactive berry natural products (BNPs) using solid phase extraction with metal‐organic frameworks (MOF‐SPE). Two pyrene‐based MOFs with different structural topologies, Al‐PyrMOF and Zr‐NU‐1000, were evaluated for their ability to capture and desorb BNPs, including ellagic acid, quercetin, gallic acid, and p‐coumaric acid. Time‐dependent BNP uptake via dispersive SPE revealed that NU‐1000 outperformed Al‐PyrMOF in capturing all BNPs. Our findings show NU‐1000 demonstrated a higher and more consistent BNP capture profile, achieving over 90 % capture of all BNPs within 36 h, with only a 9 % variation between the most and least effectively captured BNPs. In contrast, Al‐PyrMOF, displayed a staggered uptake profile, with a significant 53 % difference in capture efficiency between the most and least effectively captured BNP. However, when a BNP mixture was used at a loading concentration of 50 μg/mL, Al‐PyrMOF outperformed NU‐1000, capturing over 70 % of all BNPs. Al‐PyrMOF also exhibited improved BNP recovery, with a minimum of two‐fold greater amount recovered for all BNPs. Further testing with a BNP mixture at a concentration of 15 μg/mL demonstrated that Al‐PyrMOF efficiently concentrated all BNPs, achieving a maximum extraction factor of 2.71 observed for quercetin. These findings highlight the use of Al‐PyrMOF as a MOF‐SPE sorbent for recovering bioactive BNPs. [ABSTRACT FROM AUTHOR]

Frustrated Lewis pairs (FLPs) consist of sterically hindered Lewis acids and Lewis bases, which provide high catalytic activity towards non‐metal‐mediated activation of "inert" small molecules, including CO2 among others. One critical issue of homogeneous FLPs, however, is their instability upon recycling, leading to catalytic deactivation. Herein, we provide a solution to this issue by incorporating a bulky Lewis acid‐functionalized ligand into a water‐tolerant metal‐organic framework (MOF), named SION‐105, and employing Lewis basic diamine substrates for the in situ formation of FLPs within the MOF. Using CO2 as a C1‐feedstock, this combination allows for the efficient transformation of a variety of diamine substrates into benzimidazoles. SION‐105 can be easily recycled by washing with MeOH and reused multiple times without losing its identity and catalytic activity, highlighting the advantage of the MOF approach in FLP chemistry. Frustrated but productive: A boron‐based, water‐stable metal–organic framework heterogenous catalyst (SION‐105) for frustrated Lewis pair‐mediated conversion of CO2 is reported. Using CO2 as a C1‐feedstock, a variety of different diamine substrates were transformed into value‐added benzimidazoles. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A pyrene‐based metal‐organic framework (MOF) SION‐8 captured iodine (I2) vapor with a capacity of 460 and 250 mg g−1MOF at room temperature and 75 °C, respectively. Single‐crystal X‐ray diffraction analysis and van‐der‐Waals‐corrected density functional theory calculations confirmed the presence of I2 molecules within the pores of SION‐8 and their interaction with the pyrene‐based ligands. The I2–pyrene interactions in the I2‐loaded SION‐8 led to a 104‐fold increase of its electrical conductivity compared to the bare SION‐8. Upon adsorption, ≥95 % of I2 molecules were incarcerated and could not be washed out, signifying the potential of SION‐8 towards the permanent capture of radioactive I2 at room temperature. Trapped forever! A pyrene‐based MOF, SION‐8, efficiently adsorbs vapor iodine, however, unlike in other known materials, this capture is permanent at room temperature. The formation of the stable charge‐transfer complex SION‐8⊃I2 can be tracked with conspicuous color and electrical conductivity changes. [ABSTRACT FROM AUTHOR]

In the article "Vanillin: An Effective Additive to Improve the Longevity of Zn Metal Anode in a 30 m ZnCl2 Electrolyte," researchers P. Alex Greaney, Xiulei Ji, and their colleagues discuss the challenges of designing aqueous electrolytes for zinc metal anodes in batteries. They found that adding a small amount of vanillin to a 30 m ZnCl2 electrolyte improves the reversibility of the anode, prevents dendrite formation, and increases Coulombic efficiency. This electrolyte formulation allows for stable cycling of a zinc metal battery with an N/P ratio of 2 for over 800 cycles. [Extracted from the article]

Abstract: Iodine (I2) capture and recovery is an important process in many industrial practices. Conventional materials for I2 capture include Ag0‐based aerogels and zeolites and C‐based aerogels and powders, which suffer from expensive and/or inefficient recovery. Recently, metal–organic frameworks (MOFs) have shown potential as good adsorbents for I2 capture with high capacity, fast uptake, and good recyclability. The powder form of MOFs, however, often makes them impractical in large‐scale applications. Herein, a versatile method based on the phase inversion technique is presented to fabricate millimeter‐sized spherical MOF@polymer composite beads, and the use of these beads for I2 capture and recovery is demonstrated. Besides preserving the crystallinity and pore accessibility of the embedded MOFs in the polymeric matrix, the beads exhibit higher capacity and faster uptake rate for I2 in both vapor and liquid phases compared to the bulk MOF powder. In order to showcase the applicability of these beads, a gas‐sparged column is used as a proof‐of‐concept device that can efficiently capture and recover more than 99% of I2 from the feeding solution. The beads can be recycled and reused multiple times, which in combination with their easy handling and storage highlights their superiority compared to MOF powders in adsorption applications. [ABSTRACT FROM AUTHOR]

Recyclable materials for simultaneous detection and uptake of ammonia (NH3) are of great interest due to the hazardous nature of NH3. The structural versatility and porous nature of metal-organic frameworks (MOFs) make them ideal candidates for NH3 capture. Herein, the synthesis of a water-stable and porous 3-dimensional CuII-based MOF ( SION-10) displaying a ship-in-a-bottle structure is reported; the pores of the host SION-10 framework accommodate mononuclear CuII-complexes. SION-10 spontaneously uptakes NH3 as a result of two concurrent mechanisms: chemisorption due to the presence of active CuII sites and physisorption (bulk permanent porosity). The color of the material changes from green to blue upon NH3 capture, with the shifts of the UV/Vis absorption bands clearly seen at NH3 concentrations as low as 300 ppm. SION-10 can be recovered upon immersion of SION-10⊃NH3 in water and can be further reused for NH3 capture for at least three cycles. [ABSTRACT FROM AUTHOR]

Materials with surfaces that can be switched from high/superhydrophobicity to superhydrophilicity are useful for myriad applications. Herein, we report a metal-organic framework (MOF) assembled from ZnII ions, 1,4-benzenedicarboxylate, and a hydrophobic carborane-based linker. The MOF crystal-surface can be switched between hydrophobic and superhydrophilic through a chemical treatment to remove some of the building blocks. [ABSTRACT FROM AUTHOR]

We report herein an efficient, fast, and simple synthesis of an imine-based covalent organic framework (COF) at room temperature (hereafter, RT-COF-1). RT-COF-1 shows a layered hexagonal structure exhibiting channels, is robust, and is porous to N2 and CO2. The room-temperature synthesis has enabled us to fabricate and position low-cost micro- and submicropatterns of RT-COF-1 on several surfaces, including solid SiO2 substrates and flexible acetate paper, by using lithographically controlled wetting and conventional ink-jet printing. [ABSTRACT FROM AUTHOR]

The reaction of the chiral dipeptide glycyl- L( S)-glutamate with CoII ions produces chiral ladders that can be used as rigid 1D building units. Spatial separation of these building units with linkers of different lengths allows the engineering of homochiral porous MOFs with enhanced pore sizes, pore volumes, and surface areas. This strategy enables the synthesis of a family of isoreticular MOFs, in which the pore size dictates the enantioselective adsorption of chiral molecules (in terms of their size and enantiomeric excess). [ABSTRACT FROM AUTHOR]

The reaction of NiII with a tetra-benzoate pyrene ligand produces a 3D porous framework based on infinite 1D NiII chains. The NiII-O connectivity and the formation of a hydroxo-bridge (μ3-OH) responsible for the connection of the central NiII atoms within the 1D NiII-(μ3-OH)2-NiII chains can be straightforwardly compared with the TiIV-O-TiIV connectivity seen in TiO2. The arrangement of the TBAPy ligand around the 1D rutile-based chains leads in the generation of a porous framework with two distinct types of pores; based on the chemistries of these two types of pores, one can be labelled as hydrophobic and the other as hydrophilic. The use of different activation methods results in the generation of either a porous framework free of guest molecules or a completely solvent-free material, in which the terminal H2O molecules bound to NiII were removed, leading thus to a framework with open NiII sites. CO2 isotherms collected on both frameworks at 195 K and one barshowed type I isotherms characteristic of microporous materials (BET surface areas for: guest-free framework: 257(3) m2 ·g-1; solvent-free framework: 362(2) m2 ·g-1). The affinity of both networks at zero coverage for both CO2 and CH4 was found to be greater when the unsaturated NiII sites are available within the void space. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are among the most attractive porous materials known today, exhibiting very high surface areas, tuneable pore sizes and shapes, adjustable surface functionality, and flexible structures. Advances in the formation of MOF crystals, and in their subsequent assembly into more complex and/or composite superstructures, should expand the scope of these materials in many applications (e.g., drug delivery, chemical sensors, selective reactors and removal devices, etc.) and facilitate their integration onto surfaces and into devices. This Concept article aims to showcase recently developed synthetic strategies to control the one-, two- and three-dimensional (1-, 2- and 3D) organisation of MOF crystals. [ABSTRACT FROM AUTHOR]

Dual‐functional photocatalytic activity for simultaneous hydrogen (H2) generation and degradation of an organic pollutant is achieved under visible‐light irradiation. In article number 1806368, Kyriakos C. Stylianou and co‐workers employ a visible‐light responsive metal‐organic framework, MIL‐125‐NH2, with abundant nickel phosphide (Ni2P) nanoparticles as co‐catalysts. In a single photocatalytic process, H2 is generated in high rates and Rhodamine B is photo‐degraded. [ABSTRACT FROM AUTHOR]

Porous Materials The reaction of the chiral dipeptide glycyl ‐ L(S) ‐ glutamate with CoII ions produces chiral ladders that can be used as rigid 1D building units. Spatial separation of these building units with linkers of different lengths allows the engineering of homochiral porous MOFs with enhanced pore sizes, pore volumes, and surface areas. This strategy enables the synthesis of a family of isoreticular MOFs, in which the pore size dictates the enantioselective adsorption of chiral molecules. For more details, see the Communication by D. Maspoch et al. on page 9964 ff. [ABSTRACT FROM AUTHOR]

Frustrated Lewis pairs (FLPs) consist of sterically hindered Lewis acids and Lewis bases, which provide high catalytic activity towards non‐metal‐mediated activation of "inert" small molecules, including CO2 among others. One critical issue of homogeneous FLPs, however, is their instability upon recycling, leading to catalytic deactivation. Herein, we provide a solution to this issue by incorporating a bulky Lewis acid‐functionalized ligand into a water‐tolerant metal‐organic framework (MOF), named SION‐105, and employing Lewis basic diamine substrates for the in situ formation of FLPs within the MOF. Using CO2 as a C1‐feedstock, this combination allows for the efficient transformation of a variety of diamine substrates into benzimidazoles. SION‐105 can be easily recycled by washing with MeOH and reused multiple times without losing its identity and catalytic activity, highlighting the advantage of the MOF approach in FLP chemistry. [ABSTRACT FROM AUTHOR]

Frustrated Lewis pairs (FLPs) consist of sterically hindered Lewis acids and Lewis bases, which provide high catalytic activity towards non‐metal‐mediated activation of "inert" small molecules, including CO2 among others. One critical issue of homogeneous FLPs, however, is their instability upon recycling, leading to catalytic deactivation. Herein, we provide a solution to this issue by incorporating a bulky Lewis acid‐functionalized ligand into a water‐tolerant metal‐organic framework (MOF), named SION‐105, and employing Lewis basic diamine substrates for the in situ formation of FLPs within the MOF. Using CO2 as a C1‐feedstock, this combination allows for the efficient transformation of a variety of diamine substrates into benzimidazoles. SION‐105 can be easily recycled by washing with MeOH and reused multiple times without losing its identity and catalytic activity, highlighting the advantage of the MOF approach in FLP chemistry. Frustrated but productive: A boron‐based, water‐stable metal–organic framework heterogenous catalyst (SION‐105) for frustrated Lewis pair‐mediated conversion of CO2 is reported. Using CO2 as a C1‐feedstock, a variety of different diamine substrates were transformed into value‐added benzimidazoles. [ABSTRACT FROM AUTHOR]