Photophysics of metal-organic frameworks:A brief overview

Metal-organic frameworks(MOFs),which are self-assembled porous coordination materials,have garnered considerable attention in the fields of optoelectronics,photovoltaic,photochemistry,and photocatalysis due to their diverse structures and excellent tunability.However,the performance of MOF-based optoelectronic applications currently falls short of the industry benchmark.To enhance the performance of MOF materials,it is imperative to undertake comprehensive investigations aimed at gaining a deeper understanding of photophysics and sequentially optimizing properties related to photocarrier transport,recombination,interaction,and transfer.By utilizing femtosecond laser pulses to excite MOFs,time-resolved optical spectroscopy offers a means to observe and characterize these ultrafast microscopic processes.This approach adds the time coordinate as a novel dimension for comprehending the interaction between light and MOFs.Accordingly,this review provides a comprehensive overview of the recent advancements in the photophysics of MOFs and additionally outlines potential avenues for exploring the time domain in the investigation of MOFs.

Research progress on the substrate for metal-organic framework(MOF) membrane growth for separation

During the last decade, metal-organic frameworks(MOFs) have been applied in various fields due to their unique chemical and functional advantages. One of the widespread research hotspots is MOF-based membranes for separations, specifically continuous defect-free MOF membranes, which are usually grown on porous substrates. The substrate not only serves as the MOF layer support but also has a great influence on the membrane fabrication process and the final separation performance of the resultant membrane. In this review, we mainly introduce the progress focused on the substrates for MOF membranes fabrication. The substrate modifications and seeding methods aimed at synthesizing highquality MOF membranes are also summarized systematically.

Novel in-capsule synthesis of metal-organic framework for innovative carbon dioxide capture system

Metal-Organic Frameworks(MOFs)have been developed as solid sorbents for CO_(2) capture applications and their properties can be controlled by tuning the chemical blocks of their crystalline units.A number of MOFs(e.g.,HKUST-1)have been developed but the question remains how to deploy them for gas-solid contact.Unfortunately,the direct use of MOFs as nanocrystals would lead to serious problems and risks.Here,for the first time,we report a novel MOF-based hybrid sorbent that is produced via an innovative in-situ microencapsulated synthesis.Using a custom-made double capillary microfluidic assembly,double emulsions of the MOF precursor solutions and UV-curable silicone shell fluid are produced.Subsequently,HKUST-1 MOF is successfully synthesized within the droplets enclosed in the gas permeable microcapsules.The developed MOF-bearing microcapsules uniquely allow the deployment of functional nanocrystals without the challenge of handling ultrafine particles,and further,can selectively reject undesired compounds to protect encapsulated MOFs.

一种MOF基混合基质膜的制备及其纳滤性能

对商业化的聚丙烯腈(PAN)进行预处理改性得到基底---预处理后的聚丙烯腈(HPAN),并将研磨后的金属有机框架(metal-organic framework,MOF)材料PCN-250作为填充物与聚乙烯亚胺(PEI)共混后旋涂在HPAN基底上,得到了一种可用于纳滤的PCN-250/PEI-HPAN混合基质膜。对MOF和制备后的混合基质膜的表征显示研磨后的PCN-250在水中具有较好的分散性,并且随着膜制备过程中PCN-250使用量的增加,膜表面的粗糙度增大,膜的有效面积相应增加。由于PCN-250晶粒表面带有负电荷,它的加入使膜表面整体上电负性更高,更有利于负电荷型染料分子的截留。通过SEM和AFM表征了膜的形貌结构,并研究了MOF的不同负载率和PEI质量浓度对膜性能的影响。结果表明,PCN-250负载率为75%时,膜的纳滤性能最优,对水的渗透率可达1480 L/(m^(2)·h·MPa),对染料分子甲基蓝的截留率为97.3%。

Metal-Organic Framework Materials for Electrochemical Supercapacitors

Exploring new materials with high stability and capacity is full of challenges in sustainable energy conversion and storage systems.Metal-organic frameworks(MOFs),as a new type of porous material,show the advantages of large specific surface area,high porosity,low density,and adjustable pore size,exhibiting a broad application prospect in the field of electrocatalytic reactions,batteries,particularly in the field of supercapacitors.This comprehensive review outlines the recent progress in synthetic methods and electrochemical performances of MOF materials,as well as their applications in supercapacitors.Additionally,the superiorities of MOFs-related materials are highlighted,while major challenges or opportunities for future research on them for electrochemical supercapacitors have been discussed and displayed,along with extensive experimental experiences.

An Overview of Metal-Organic Frameworks for Green Chemical Engineering

Given the current global energy and environmental issues resulting from the fast pace of industrialization,the discovery of new functional materials has become increasingly imperative in order to advance science and technology and address the associated challenges.The boom in metal–organic frameworks(MOFs)and MOF-derived materials in recent years has stimulated profound interest in exploring their structures and applications.The preparation,characterization,and processing of MOF materials are the basis of their full engagement in industrial implementation.With intensive research in these topics,it is time to promote the practical utilization of MOFs on an industrial scale,such as for green chemical engineering,by taking advantage of their superior functions.Many famous MOFs have already demonstrated superiority over traditional materials in solving real-world problems.This review starts with the basic concept of MOF chemistry and ends with a discussion of the industrial production and exploitation of MOFs in several fields.Its goal is to provide a general scope of application to inspire MOF researchers to convert their focus on academic research to one on practical applications.After the obstacles of cost,scale-up preparation,processability,and stability have been overcome,MOFs and MOF-based devices will gradually enter the factory,become a part of our daily lives,and help to create a future based on green production and green living.

A Three-dimensional Porous Metal-organic Framework Based on Cyano Unit and 1,4-Bis(1,2,4-triazol-1-yl)butane(btb):{[Cu_8(btb)_2(CN)_8].3H_2O}_n

The title coordination polymer 1,{[Cu8（btb）2（CN）8].3H2O}n（btb = 1,4-bis（1,2,4-triazol-1-yl）butane）,has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction.Complex 1 crystallizes in monoclinic,space group C2/c with a = 1.2938（3）,b = 1.9422（5）,c = 0.9406（2） nm,β = 121.891（4）°,V = 2.0066（9） nm3,C24H30Cu8N20O3,Mr = 1155.00,Dc = 1.912 g/cm3,μ（MoKα） = 4.209 mm？1,F（000） = 1140,GOF = 1.184,Z = 2,the final R = 0.0634 and wR = 0.1503 for I 2σ（I）.In complex 1,one-dimensional CuCN zigzag chains are linked by triazolyl groups of btb ligands to form two-dimensional networks,which are further bridged by 1,4-butyl moieties of btb ligands to fabricate a three-dimensional order framework,in which one-dimensional ellipsoid-like channels are observed.

Equilibrium,Kinetics and Thermodynamics of the Adsorption of Methylene Blue onto a Metal-Organic Frameworks Material,Copper Coordination Polymer with Dithiooxamide

The equilibrium, kinetics and thermodynamics of the adsorption of methylene blue( MB) from aqueous solution onto copper coordination polymer with dithiooxamide( H2dtoaCu),one of the metal-organic frameworks( MOFs),were investigated in a batch adsorption system as a function of initial pH, adsorbent concentration, contact time, initial dye concentration, and temperature. The Langmuir, Freundlich, and DubininRadushkevich( D-R) isotherm models were used for modeling the adsorption equilibrium. It was found that Langmuir model yielded a much better fit than the Freundlich model under different temperatures. The maximum monolayer adsorption capacities of MB were 192. 98,229. 86,and 297. 38 mg /g at 298,308,and 318 K,respectively. The calculated mean adsorption energy( 8. 26-11. 04 kJ /mol) using D-R model indicated that the adsorption process might take place by chemical adsorption mechanism.Otherwise,the kinetic studies revealed that the adsorption process could be well explained by pseudo-second-order rate kinetics and intraparticle diffusion was not the rate-limiting step.Thermodynamic studies indicated that this system was feasible,spontaneous,and endothermic process. Based on these studies,H2dtoaCu can be considered as a potential adsorbent for the removal of MB from aqueous solution.

Novel Metal-organic Framework Compound Pb(C_5H_4NCOO)_2 Showing One-dimensional Channel Defined as Four Leads and Four Nicotinic Acids

A novel metal-organic framework（MOF） compound of Pb（C5H4NCOO）2 was hydrothermally synthesized and structurally determined by X-ray single-crystal diffraction. The data of unit cell： orthorhombic space group Pccn, a=1.0325（2） nm, b=1.3597（3） nm, c=0.8499（2） nm, V=1.1931（4） nm^3, Z=4, Dc=2.513 g/cm^3, R1=0.047 were obtained on the basis of 1365 reflections with Fo〉2σ（Fo）. PbN2O6 polyhedron adopts the distorted cubic configuration which is assigned to the holodirected geometry. These PbN2O6 polyhedra can form the zigzag chain by edge-sharing mode along（001） direction. Pb atom is connected by six nicotinic acid molecules, leading neutral 3D metal-organic framework with a channel defined by four Pb atoms and four nicotinic acid molecules.

The effects of amino groups and open metal sites of MOFs on polymer-based electrolytes for all-solid-state lithium metal batteries

Metal-organic frameworks(MOFs) are becoming more and more popular as the fillers in polymer electrolytes in recent years. In this study, a series of MOFs(NH_(2)-MIL-101(Fe), MIL-101(Fe), activated NH_(2)-MIL-101(Fe) and activated MIL-101(Fe)) were synthesized and added to PEO-based solid composite electrolytes(SCEs). Furthermore, the role of the —NH_(2) groups and open metal sites(OMSs) were both examined. Different ratios of MOFs vs polymers were also studied by the electrochemical characterizations. At last, we successfully designed a novel solid composite electrolyte containing activated NH_(2)-MIL-101(Fe),PEO, Li TFSI and PVDF for the high-performance all-solid-state lithium-metal batteries. This work might provide new insight to understand the interactions between polymers and functional groups or OMSs of MOFs better.

Nanoscale Metal-Organic Frameworks:Stimulus-Response and Applications

Metal-organic frameworks(MOFs),a crystalline porous material with a periodic net-work structure formed by the self-assembly of transition metal ions and organic ligands,have been widely applied in various fields due to their rich composition and structural diversity.Among vari-ous types of MOFs,stimuli-responsive MOFs have gained increasing attention in recent years,because of their broad application in the field of physics,biology,and chemistry.In this review,we analyzed and classified the mechanism of stimulus-response MOFs(pH response,glucose response,GSH response,light response,temperature response)and their applications in drug delivery,adsorption and luminescence functions,magnetization and catalysis functions,probe and sensor.

MOF-5的原位电化学合成及其在提高BiOBr光催化活性方面的应用(英文)

金属有机骨架材料(MOFs)是一种重要的功能材料,通过原位电化学合成方法在离子液体1-丁基-3-甲基咪唑氯盐作为模板剂的条件下合成MOF-5(IL)(Zn4O(BDC)(BDC=1,4-苯二甲酸)。π-π堆叠作用、离子键和配位键的相互作用使得MOF-5(IL)形成球状结晶。分析结果表明:通过电化学法在离子液体中合成的MOF-5(IL)比传统溶剂热法合成的MOF-5表现出更好的结晶性和更高的热稳定性。循环伏安曲线显示该电化学合成反应是一个扩散控制的不可逆过程。对甲基橙的降解实验表明,MOF-5(IL)独特的结构特征可以提高Bi OBr的光催化活性。因此,MOFs材料可以取代贵金属来提高卤氧铋的光催化性能。

MOF基材料绿色催化CO_(2)还原研究进展

CO_(2)的资源化转化与利用是"双碳"目标达成的重要途径之一.金属-有机框架(metal-organic framework, MOF)因其充足的孔结构、丰富的活性位和可功能化等特性,在CO_(2)催化还原反应中展现出良好的应用前景.总结了基于MOF的新型功能材料依托光、电清洁能源,绿色催化CO_(2)还原的最新研究进展,分别探讨了活性MOF、MOF复合物和MOF衍生物的催化性能,并从理化特性上分析了材料性能优势的成因.在此基础上,对这类新型催化剂面临的主要问题和未来发展做出了总结与展望.

金属有机骨架在水中污染物检测中的应用研究进展

水体中的有毒重金属和有机污染物已引起全世界的广泛关注,开发有效的手段,快速检测这些污染物具有重要意义。作为新材料领域研究的热点,有机金属骨架(Metal-Organic Frameworks,MOFs)因具有高孔隙率和大内表面积正被逐步引入食品、环境监测等领域。本文对MOFs材料在水中污染物检测中的应用进行综述,为实现MOFs材料的商业化应用指明研究方向。

Dimensional reduction enhances photocatalytic carbon dioxide reduction performance of metal-organic frameworks

Metal-organic frameworks(MOFs)have shown significant potential as photocatalysts.It has been widely assumed that all catalytic active sites within MOFs are functional in photocatalytic reactions but for a three-dimensional MOF,whether the internal catalytic active sites can effectively absorb light and actively contribute to photocatalytic reactions remains to be explored.In this context,we synthesized a two-dimensional nanosheet MOF(2D-MOF)and a three-dimensional bulk MOF(3D-MOF)composed of Zr^(6) clusters and tetracarboxylic porphyrin(TCPP)by the approach described in the literature.Re(bpy)(CO)^(3)Cl(bpy=2,2’-bipyridine),which has remarkable CO_(2) photoreduction ability,was introduced to the two MOFs to create two new photocatalysts 2D-MOF-Re and 3D-MOF-Re,respectively.Photocatalytic CO_(2) reduction experiments show that based on the equal number of catalytic active sites,the CO turnover number(TON)of 2D-MOF-Re reaches 27.8 in 6 h,which is 50 times that of 3D-MOF-Re.The result shows that certain catalytic active sites inside the bulk MOF are inactive due to the inability to absorb light.This study illuminates the potential of the dimensional reduction approach in the design of photocatalysts to exploit the capabilities fully.

Enhanced carbon capture with motif-rich amino acid loaded defective robust metal-organic frameworks

The use of metal-organic frameworks(MOFs)as solid adsorption materials for carbon capture is promising,but achieving efficient and reversible adsorption with a balance of capacity and selectivity for carbon dioxide(CO_(2))over N_(2) remains a challenge.To take full advantage of the strong channel traffic and robustness of MOFs with relatively small pores,it is highly necessary to employ a defect-engineering strategy to construct a broader channel structure that can facilitate the loading of functional motif-rich amino acids(AAs).This strategy can greatly enhance the CO_(2) adsorption performance of MOF.In this study,motif-rich amino acids are loaded into the defective and robust porous frameworks via combined defect-engineering and post-synthetic methods.The defective Zr/Hf-MOF-808s modified with AAs,especially for the 18 mol%4-nitroisophthalic acid,generated defective products allowing for the loading of L-serine(L-Ser).This modification resulted in a significant improvement in both the adsorption capacity(248%improvement at 298 K,100 kPa)and the selectivity of CO_(2)/N_(2) using the ideal adsorbed solution theory(IAST),with the selectivity increasing to 120.55 and 38.27 at 15 and 100 kPa,respectively,while maintaining good cycling performance.Density functional theory(DFT)simulation,CO_(2) temperature-programmed desorption(CO_(2)-TPD),and in situ Fourier transform infrared spectroscopy(FTIR)were further employed to have a better understanding of the enhanced CO_(2) adsorption capacity.Interestingly,unlike the AAs loaded pristine MOF-808s that showed the best CO_(2) adsorption capacity with the loading of short and small glycine(Gly),the broadened channel size in our work enables the loading of functional motif-rich L-serine,which brings more active binding sites,improving CO_(2) adsorption.

Activity regulation and applications of metal-organic framework-based nanozymes

As a new generation of artificial enzymes,nanozymes show outstanding advantages such as high stability,low cost,and facile synthesis,which endow them with promising applications in biomedical and environmental fields.Among the various reported nanozymes,metal-organic frameworks(MOFs)could mimic the active center of natural enzymes and provide a hydrophobic environment,which makes MOFs attractive alternatives to natural enzymes.Owing to the highly structural diversity and tailorability of MOFs,rational design will contribute to improve the activity of MOF-based nanozymes and promote their potential applications in both biomedical and environmental fields.Therefore,a comprehensiye suminary of activity regulatory strategies of MOF-based nanozymes is urgently needed.Firstly,we summarized the activity regulatory strategies of MOFs with intrinsic enzyme-like activities via modulation of metal nodes,ligands,structures and morphologies.Then the applications of MOF-based nanozymes in biosensing,hazardous degradation,antibacterial,and cancer therapy were also introduced.Finally,the current challenges and future perspectives were discussed in depth.It is highly expected that this review will provide a better understanding on the rational design of novel high-performance MOF-based nanozymes.

Coupling metal-organic frameworks and wood-based carbon for water remediation

Fresh and clean water is highly demanded throughout the world.To effectively address the need,nanomaterials enabled nanotechnology has been explored as a means of more efficient,reliable,and environmentally friendly approach towards water treatment practices.One concern in adopting nanomaterials is how to retrieve them from water body to avoid secondary contamination.In this work,the earth abundant and sustainable wood,e.g.,basswood,was selected and carbonized into porous carbon as host skeleton,and metal-organic frameworks(MOFs),e.g.,MOF-199 with extremely high surface area,were grown throughout all channels in the porous basswood carbon.Targeting the traditional organic pollutant,methyl orange(MO),the combination of MOFs and basswood carbon(MOFs@carbon)demonstrates a remarkable adsorption capacity,which is 243%and 454%higher than basswood carbon and MOF-199,respectively.Such an outstanding adsorption performance originates from that the positively charged carbon pulls MO molecules close to carbon surface,leading to a high MO molecule concentration,and then the concentration gradient drives the MO molecules to be stored inside MOFs,functioning like pockets.These findings highlight the potential application of coupled MOFs and biomass carbon in addressing water remediation.

ROS Balance Autoregulating Core-Shell CeO_(2)@ZIF-8/Au Nanoplatform for Wound Repair

Reactive oxygen species(ROS)plays important roles in living organisms.While ROS is a double-edged sword,which can eliminate drug-resistant bacteria,but excessive levels can cause oxidative damage to cells.A core–shell nanozyme,Ce O_(2)@ZIF-8/Au,has been crafted,spontaneously activating both ROS generating and scavenging functions,achieving the multifaceted functions of eliminating bacteria,reducing inflammation,and promoting wound healing.The Au Nanoparticles(NPs)on the shell exhibit high-efficiency peroxidase-like activity,producing ROS to kill bacteria.Meanwhile,the encapsulation of Ce O_(2) core within ZIF-8 provides a seal for temporarily limiting the superoxide dismutase and catalase-like activities of Ce O_(2) nanoparticles.Subsequently,as the ZIF-8 structure decomposes in the acidic microenvironment,the Ce O_(2) core is gradually released,exerting its ROS scavenging activity to eliminate excess ROS produced by the Au NPs.These two functions automatically and continuously regulate the balance of ROS levels,ultimately achieving the function of killing bacteria,reducing inflammation,and promoting wound healing.Such innovative ROS spontaneous regulators hold immense potential for revolutionizing the field of antibacterial agents and therapies.

Classical spin liquid state in a rhombic lattice metal-organic framework

Discovering more and new geometrically frustrated systems remains an active point of inquiry in fundamental physics for the existence of unusual states of matter.Here,we report spin-liquid-like behavior in a two-dimensional(2D)rhombic lattice Fe-metal-organic framework(Fe-MOF)with frustrated antiferromagnetism.This Fe-MOF exhibits a high frustration factor f=|θCW|/TN≥315,and its long-range magnetic order is suppressed down to 180 mK.Detailed theoretical calculations demonstrate strong antiferromagnetic coupling between adjacent Fe3+ions,indicating the potential of a classical spin-liquid-like behavior.Notably,a T-linear heat capacity parameter,γ,originating from electronic contributions and with magnetic field independence up to 8 T,can be observed in the specific heat capacity measurements at low-temperature,providing further proof for the spin-liquid-like behavior.This work highlights the potential of MOF materials in geometrically frustrated systems,and will promote the research of exotic quantum physics phenomena.