Titanium metal–organic frameworks (Ti‐MOFs), as an appealing type of artificial photocatalyst, have shown great potential in the field of solar energy conversion due to their well‐studied photoredox ...activity (similar to TiO2) and good optical responsiveness of linkers, which serve as the antenna to absorb visible‐light. Although much effort has been dedicated to developing Ti‐MOFs with high photocatalytic activity, their solar energy conversion performances are still poor. Herein, we have implemented a covalent‐integration strategy to construct a series of multivariate Ti‐MOF/COF hybrid materials PdTCPP⊂PCN‐415(NH2)/TpPa (composites 1, 2, and 3), featuring excellent visible‐light utilization, a suitable band gap, and high surface area for photocatalytic H2 production. Notably, the resulting composites demonstrated remarkably enhanced visible‐light‐driven photocatalytic H2 evolution performance, especially for the composite 2 with a maximum H2 evolution rate of 13.98 mmol g−1 h−1 (turnover frequency (TOF)=227 h−1), which is much higher than that of PdTCPP⊂PCN‐415(NH2) (0.21 mmol g−1 h−1) and TpPa (6.51 mmol g−1 h−1). Our work thereby suggests a new approach to highly efficient photocatalysts for H2 evolution and beyond.
A series of covalently connected multivariate Ti‐MOF/COF hybrid materials were constructed demonstrating outstanding photocatalytic H2 evolution performance with a maximum H2 evolution rate of 13.98 mmol g−1 h−1 (TOF=227 h−1), much higher than the prototypical counterparts.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
We transformed the hydrophilic metal–organic framework (MOF) UiO‐67 into hydrophobic UiO‐67‐Rs (R=alkyl) by introducing alkyl chains into organic linkers, which not only protected hydrophilic Zr6O8 ...clusters to make the MOF interspace superoleophilic, but also led to a rough crystal surface beneficial for superhydrophobicity. The UiO‐67‐Rs displayed high acid, base, and water stability, and long alkyl chains offered better hydrophobicity. Good hydrophobicity/oleophilicity were also possible with mixed‐ligand MOFs containing metal‐binding ligands. Thus, a (super)hydrophobic MOF catalyst loaded with Pd centers efficiently catalyzed Sonogashira reactions in water at ambient temperature. Studies of the hydrophobic effects of the coordination interspace and the outer surface suggest a simple de novo strategy for the synthesis of superhydrophobic MOFs that combine surface roughness and low surface energy. Such MOFs have potential for environmentally friendly catalysis and water purification.
Simply super: Alkyl chains were introduced into the organic linkers of UiO‐67 to provide highly chemically stable hydrophobic MOFs. The alkyl groups protected the hydrophilic Zr6O8 clusters and made the MOF interspace superoleophilic, as well as generating a rough crystal surface for superhydrophobicity. The MOFs are suitable for oil/water separation and water purification, and were modified with metal‐binding ligands for environmentally friendly catalysis.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Herein, a dynamic spacer installation (DSI) strategy has been implemented to construct a series of multifunctional metal—organic frameworks (MOFs), LIFM‐61/31/62/63, with optimized pore space and ...pore environment for ethane/ethylene separation. In this respect, a series of linear dicarboxylic acids were deliberately installed in the prototype MOF, LIFM‐28, leading to a dramatically increased pore volume (from 0.41 to 0.82 cm3 g−1) and reduced pore size (from 11.1×11.1 Å2 to 5.6×5.6 Å2). The increased pore volume endows the multifunctional MOFs with much higher ethane adsorption capacity, especially for LIFM‐63 (4.8 mmol g−1), representing nearly three times as much ethane as the prototypical counterpart (1.7 mmol g−1) at 273 K and 1 bar. Meanwhile, the reduced pore size imparts enhanced ethane/ethylene selectivity of the multifunctional MOFs. Theoretical calculations and dynamic breakthrough experiments confirm that the DSI is a promising approach for the rational design of multifunctional MOFs for this challenging task.
A dynamic spacer installation (DSI) strategy has been developed to realize a series of multifunctional metal—organic frameworks (MOFs) with optimized pore space and pore environment for ethane/ethylene separation. The installation of functional spacers into the proto‐LIFM‐28 not only improves the pore volume, but also reduces the pore size, leading to enhanced C2H6/C2H4 separation performance.
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The indoor air quality is of prime importance for human daily life and health, for which the adsorbents like zeolites and silica‐gels are widely used for air dehumidification and harmful gases ...capture. Herein, we develop a pore‐nanospace post‐engineering strategy to optimize the hydrophilicity, water‐uptake capacity and air‐purifying ability of metal‐organic frameworks (MOFs) with long‐term stability, offering an ideal candidate with autonomous multi‐functionality of moisture control and pollutants sequestration. Through variant tuning of organic‐linkers carrying hydrophobic and hydrophilic groups in the pore‐nanospaces of prototypical UiO‐67, a moderately hydrophilic MOF (UiO‐67‐4Me‐NH2‐38 %) with high thermal, hydrolytic and acid‐base stability is screened out, featuring S‐shaped water sorption isotherms exactly located in the recommended comfortable and healthy ranges of relative humidity for indoor ventilation (45 %–65 % RH) and adverse health effects minimization (40–60 % RH). Its exceptional attributes of water‐uptake working capacity/efficiency, contaminants removal, recyclability and regeneration promise a great potential in confined indoor environment application.
A moderately hydrophilic MOF of UiO‐67‐4Me‐NH2‐38 % with high thermal, hydrolytic and acid‐base stability has been obtained by a pore‐nanospace post‐engineering strategy, which shows ideal S‐shaped water‐sorption isotherm, high water‐uptake working capacity and efficiency in the ASHRAE recommended humidity range, and prior capture ability of harmful organic and inorganic vapors, providing a promising candidate for autonomous indoor humidity control and air purification.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
To combine flexibility and modifiability towards a more controllable complexity of MOFs, a post‐synthetic variable‐spacer installation (PVSI) strategy is used to implement kinetic installation/ ...uninstallation of secondary ligands into/from a robust yet flexible proto‐Zr‐MOF. This PVSI process features precise positioning of spacers with different length, size, number, and functionality, enabling accurate fixation of successive breathing stages and fine‐tuning of pore surface. It shows unprecedented synthetic tailorability to create complicated MOFs in a predictable way for property modification, for example, CO2 and R22 adsorption/separation, thermal/chemical stability, and extended breathing behavior.
Bringing PSM into dynamic MOFs: Post‐synthetic modification (PSM) is used to install/uninstall varied linkers into/from a flexible Zr‐MOF. This post‐synthetic variable‐spacer installation (PVSI) strategy is used to tune elastic deformation, breathing behavior, and stabilization of the framework in controllable and predictable way. Tuning the pore surface leads to a larger surface area and improved gas separation and adsorption capacity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In multiphoton excited fluorescence (MPEF), high‐energy upconversion emission is obtained from low‐energy excitation by absorbance of two or more photons simultaneously. In a pressure‐induced ...fluorochromic process, the emission energy is switched by outer pressure stimuli. Now, five metal–organic frameworks containing the same ligand with simultaneous multiphoton absorption and pressure‐induced fluorochromic attributes were studied. One‐, two‐, and three‐photon excited fluorescence (1/2/3PEF) can be achieved in the frameworks, which exhibit pressure‐induced blue‐to‐yellow fluorochromism. The performances are closely dependent with the topologies, flexibilities, and packing states of the frameworks and chromophores therein. The multiphoton upconversion performance can be intensified by pressure‐related structural contraction. Over ten‐fold increment in the 2PA active cross‐section up to 2217 GM is achieved in pressed LIFM‐114 compared with the 210 GM for pristine sample at 780 nm.
Easy as 1/2/3: 1/2/3PEF (photon‐excited fluorescence) was correlated with pressure‐induced fluorochromism in MOFs. The multiphoton excited fluorochromic performance can be greatly enhanced after pressure stimulation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Known for excellent stability, porosity and functionality, the high‐valent Zr4+ metal–organic frameworks (Zr‐MOFs) still meets synthetic challenge in modulating the strength of Zr‐Ocarboxylate ...linkage. Herein we explore the unusual coordination dynamics of fluorinated Zr‐MOFs by designing two trifluoromethyl modified ligands with distinct geometry preference to form a family of thermodynamic and kinetic products. The low‐connecting kinetic Zr‐MOFs possess substitutable coordination sites to endow Zr6‐cluster with extra dynamic behaviors, thus opening a post‐synthetic pathway to sequential reassembly/disassembly processes. Comprehensive factors, including ligand geometry, Zr6‐cluster connectivity, acid modulator and reaction temperature/concentration, have been studied for controllable syntheses. The stability, hydrophobicity and gas adsorption/separation properties of obtained Zr‐MOFs are explored. This work sheds light on the understanding of the dynamic coordination chemistry of Zr‐MOFs beyond strong Zr−O bond, which poses a versatile platform for modification and functionalization of Zr‐MOFs.
The unusual coordination dynamics of seven fluorinated Zr‐MOFs were explored by designing two trifluorometyl functionalized ligands. Comprehensive factors for controllable syntheses and transformations have been discussed. The stability, hydrophobicity, and gas adsorption selectivities have been studied to elucidate the structure‐property relationship. This work demonstrates that dynamic Zr‐MOFs can be a versatile platform for functionalization.
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A 3D porous perchlorinated metal–organic framework (MOF), LIFM‐26, featuring dual functionality, that is, functional polar groups and open metal sites, has been synthesized using perchlorinated ...linear dicarboxylate to link trigonal prismatic Fe3(μ3‐O) units. LIFM‐26 exhibits good thermal and chemical stability, and possesses high porosity with a BET surface area of 1513 m2 g−1, compared with isoreticular MOF‐235 and Fe3O(F4BDC)3(H2O)3 (F4BDC=2,3,5,6‐tetrafluorobenzene‐1,4‐dicarboxylate). Most strikingly, LIFM‐26 features good gas sorption/separation performance at 298 K and 1 atm with IAST selectivity values reaching up to 36, 93, 23, 11, 46, and 202 for CO2/CH4, CO2/N2, C2H4/CH4, C2H6/CH4, C3H8/CH4, and R22/N2 (R22=CHClF2), respectively, showing potential for use in biogas/natural gas purification and CO2/R22 capture.
A versatile MOF: A 3D porous perchlorinated metal–organic framework (MOF), LIFM‐26, featuring dual functionality, polar functional groups, and open metal sites, has been synthesized and characterized. It shows good thermal and chemical stability. In addition, it exhibits excellent adsorption selectivities for CO2 versus N2 and CH4, C2+ hydrocarbons versus CH4, and CHClF2 (R22) versus N2.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
We present a new spatial public goods game model, which takes the individual reputation and behavior diversity into account at the same time, to investigate the evolution of cooperation. Initially, ...each player x will be endowed with an integer Rx between 1 and Rmax to characterize his reputation value, which will be adaptively varied according to the strategy action at each time step. Then, the agents play the game and the system proceeds in accordance with a Fermi-like rule, in which a multiplicative factor (wy) to denote the individual difference to perform the strategy transfer will be placed before the traditional Fermi probability. For influential participants, wy is set to be 1.0, but be a smaller value w (0<w<1) for non-influential ones. Large quantities of simulations demonstrate that the cooperation behavior will be obviously influenced by the reputation threshold (RC), and the greater the threshold, the higher the fraction of cooperators. The origin of promotion of cooperation will be attributed to the fact that the larger reputation threshold renders the higher heterogeneity in the fraction of two types of players and strategy spreading capability. Our work is conducive to a better understanding of the emergence of cooperation within many real-world systems.
•A spatial PGG model considering individual reputation and diversity is proposed.•The individual reputation can be adaptively changed as the system proceeds.•The reputation threshold determines the individual assortment.•The influential players own the stronger capability to persuade their neighbors.•The reputation assortment leads to the enhancement of individual heterogeneity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
