Metal-organic Frameworks Research Articles

Deep-Eutectic-Solvent-Decorated Metal-Organic Framework for Food and Environmental Sample Preparation.

Deep eutectic solvent (DES) is distinguished by its unique solvent properties, chemical stability, and eco-friendly nature, which are pivotal in a spectrum of chemical processes. It enhances the sample preparation process by increasing efficiency and minimizing the environmental impact. Metal-organic frameworks (MOFs), which are porous structures formed through coordination bonds between metal ions and organic ligands, are defined by their adjustable pore dimensions, extensive surface areas, and customizable architectures. The integration of DES within MOF to create DES@MOF capitalizes on the beneficial attributes of both materials, augmenting MOFs' stability and versatility while providing a multifunctional carrier for DES. This composite material is both highly stable and readily tunable, establishing it as a leading contender for applications in sample preparation for food and environmental samples. This comprehensive review explores the application of DES-decorated MOF in food and environmental sample preparation and highlights the expansive potential of DES@MOF in diverse fields. We provide a detailed analysis of the characteristics of DES@MOF and its individual components, methods for decorating MOFs with DES, the advantages of these composite materials in sample pretreatment, and their specific applications in food safety and environmental monitoring. DESs are employed to modify MOFs, offering a multitude of benefits that can substantially improve the overall performance and applicability of MOFs. The review also discusses current challenges and future directions in this field, offering valuable insights for further research and development. The synergistic effects of DES and MOFs offer new opportunities for applications in food safety and other areas, leading to the development of more efficient, sensitive, and environmentally friendly analytical methods. This collaboration paves the way for sustainable technologies and innovative solutions to complex challenges.

Research Progress of Cobalt-Based Metal Organic Frameworks and Their Derivatives in Energy Storage and Conversion.

With the rapid development of modern society, the efficient development and utilization of new energy have become more and more important. The development of high-performance energy storage and conversion devices has a decisive impact on the sustainable and efficient use of energy. In the foreseeable future, the exploration of high-quality functional materials for energy storage and conversion will continue to be the main goal pursued by the scientific and application fields. Metal organic frameworks (MOFs) have the merits of adjustable porosity and a stable structure. Moreover, the metal elements in the MOFs could play a role as active sites during the electrochemical process. Thus, various kinds of MOFs and their derivatives have been prepared and used as functional materials for energy storage and conversion. In this work, the applications and potentials of cobalt-based MOFs (Co-MOFs) and their derivatives in supercapacitors, advanced batteries, and electrochemical catalysts have been reviewed and summarized. The electrochemical properties, energy storage and conversion mechanisms, and the effects on performance were described in depth. A large number of Co-MOFs with unique structures, as well as numerous Co-MOF derivatives and composites, have been developed, and excellent application performance has been achieved, which have already become some of the most advantageous functional materials in the energy storage and conversion field. In addition, the current research status, difficulties, and prospects of Co-based MOFs and their derivatives as energy storage and conversion functional materials were comprehensively summarized at the end of this study.

Differentiated Intra-Ligand Charge Transfer Boosting Multicolor Responsive MOF Heterostructures as Robust Anti-Counterfeiting Labels.

Metal-organic framework (MOF) heterostructures with hybrid architectures and abundant functional sites possess great potential applications in advanced information security, yet still suffer from the harsh stimuli mechanisms with restrained emission control. Herein, the differentiated design strategy on intra-ligand charge transfer is first reported to realize smart-responsive multicolor MOF heterostructures as robust anticounterfeiting labels. Designed similar MOF blocks with the differentiated intra-ligand charge transfer are integrated via time-dependent epitaxial growth to form multicolor MOF heterostructures. Different numbers of electron-donating groups in MOF blocks offer distinct space regulation on the torsion of charge transfer ligands, which trigger the diverse responsive emissions under the same mild stimuli, thus generating multiple tunable color patterns in heterostructures. These spatial-resolved MOF heterostructures with stable multicolor responsive modes permit the encoding of fingerprint information, which further functions as robust anti-counterfeiting labels with high-security convert states. These results offer a promising route for the function-oriented exploitation of smart-responsive MOF heterosystems for advanced information anticounterfeiting.

Metal‐Organic Frameworks (MOFs) for Glucose Sensing: Advancing Non‐Invasive Detection Strategies in Diabetes Management

AbstractEffective glucose monitoring is critical for managing diabetes and preventing its associated complications. While commercial glucose monitoring devices predominantly rely on blood samples, emerging research focuses on detecting glucose in alternative biofluids, harnessing advanced nanomaterials. Among these, Metal‐Organic Frameworks (MOFs), composed of metal ions and organic ligands, have garnered significant attention due to their unique properties, including tunable porosity, high surface area, and abundant active sites conducive to glucose interaction. MOFs present a versatile platform for glucose sensing, offering potential in both enzymatic and non‐enzymatic detection methods. This review delves into the recent advancements in MOFs‐based electrochemical glucose sensors, providing a comprehensive analysis of various MOFs and their composites as electrode materials. The discussion highlights the structural attributes, functionalization strategies, and electrochemical performance of MOFs in glucose sensing, emphasizing their role in the development of next‐generation, non‐invasive glucose monitoring technologies. The review provides a comprehensive overview on the application of MOFs and MOFs‐based composites in both enzymatic and non‐enzymatic electrochemical‐based glucose sensing and highlights the synthesis, mechanism, functionalization and development in the detection strategy of MOFs in glucose sensing.

Co-Carbonization of Straw and ZIF-67 to the Co/Biomass Carbon for Electrocatalytic Nitrate Reduction

Electrocatalytic nitrate reduction enables the recovery of nitrate from water under mild conditions and generates ammonia for nitrogen fertilizer feedstock in an economical and green means. In this paper, Co/biomass carbon (Co/BC) composite catalysts were prepared by co-carbonization of straw and metal–organic framework material ZIF-67 for electrocatalytic nitrate reduction using hydrothermal and annealing methods. The metal–organic framework structure disperses the catalyst components well and provides a wider specific surface area, which is conducive to the adsorption of nitrate and the provision of more reactive active sites. The introduction of biomass carbon additionally enhances the electrical conductivity of the catalyst and facilitates electron transport. After electrochemical testing, Co/BC-100 exhibited the best performance in electrocatalytic nitrate reduction to ammonia, with an ammonia yield of 3588.92 mmol gcat.−1 h−1 and faradaic efficiency of 97.01% at −0.5 V vs. RHE potential. This study provides a promising approach for the construction of other efficient cobalt-based electrocatalysts.

Synthesis and Biomedical Applications of Covalent Organic Frameworks for Disease Diagnosis and Therapy.

Covalent organic frameworks (COFs) have emerged as a distinguished class of porous materials. Owing to their ability to be constructed through covalent bonds involving light elements, such as hydrogen, boron, carbon, nitrogen, and oxygen, COFs offer greater stability and lower cytotoxicity than metal organic frameworks do, addressing critical limitations in in vivo applications. Their unique attributes, such as high surface area, customizable pore sizes, and versatile surface functionalities, make them ideal for various biomedical applications. This review aims to provide an overview of the recent advancements in modern COFs for biomedical uses. First, a variety of methods for the synthesis of COFs are outlined, which ensures their suitability for medical use. Next, we delve into innovative biomedical applications, emphasizing their role in disease diagnostics and therapies. Finally, challenges, such as clinical translation, biocompatibility, and controlled drug release, are critically discussed, providing comprehensive insight into the potential of COFs in revolutionizing biomedical technologies. Overall, this review offers a comprehensive overview of COFs' capabilities and future prospects in enhancing biomedical technologies.

Dual Signature of Chirality Induced Spin Selectivity through Spontaneous Resolution of 2D Metal–Organic Frameworks

AbstractThe Chiral‐Induced Spin Selectivity (CISS) effect has emerged as a fascinating phenomenon within the realm of electron's spin manipulation, showcasing a unique interplay between electron's spin and molecular chirality. Subsequent to its discovery, researchers have been actively involved in exploring the new chiral molecules as effective spin filters. In the realm of observing the CISS effect, the conventional approach has mandated the utilization of two distinct enantiomers of chiral molecules. However, this present study represents a significant advancement by demonstrating the ability to control both spin states of electrons in a single system. In this work, we have demonstrated the preparation of chiral metal–organic frameworks (MOFs) via a “spontaneous resolution” process, obviating the requirement for chiral sources. This resulted in the production of chiral crystals exhibiting opposite handedness (1P and 1M) and these crystals were subsequently employed as a new class of spin filters based on CISS effect. Remarkably, this work signifies the first instance of achieving dual signature of spin selectivity from a single and exclusively achiral system through a spontaneous resolution process. This holds immense potential as it facilitates the production of two distinct spin‐filtering materials from a unified system. Furthermore, we investigated the contact potential differences (CPD) of these chiral crystals and, for the first time, associated it with the preferential spin transport properties. Our findings revealed a correlation between the CPD and the chirality of the crystals, as well as the magnetization orientations of the ferromagnetic substrate, which can be elucidated by the CISS effect. In overall, the significant findings achieved using these robust and easily synthesized MOF crystals without the requirement for chiral medium represent a crucial advancement in enhancing the effectiveness of spin filtering materials to produce spintronic devices.

Robust and sensitive colorimetric detection of glutathione with double-triggering MOF-Fe(DTNB)

Glutathione (GSH) levels have been well validated to correlate with a variety of physiological and pathological conditions, such as malignancy, cardiovascular disease and aging, making the development of accurate, robust and sensitive GSH detection methods highly desirable. In this study, a novel metal–organic framework (MOF-Fe(DTNB))-based colorimetric method with a favorable dual-triggering function was proposed. MOF-Fe(DTNB) exhibits high peroxidase activity, which can catalyze the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue ox-TMB by hydrogen peroxide (H2O2). This oxidation process of TMB can be inhibited not only by the reducing action of GSH, but also by the thiol exchange reaction between DTNB and GSH, in which the disulfide bond of DTNB in MOF-Fe(DTNB) is cleaved. Thus, with this dual triggering mechanism, the GSH concentration can be robustly measured in the MOF-Fe(DTNB)-derived colorimetric strategy. Significantly, this method is accurate (RSD < 6 %), selective and sensitive in biological plasma samples, with satisfactory recovery rates (96.7–103.3 %). It requires less instrumentation and has less interference from other substances. The linear range of the method is 0–80 µM, and the detection limit is as low as 0.28 µM. This dual-triggering MOF-Fe(DTNB)-derived colorimetric strategy has greatly simplified the GSH detection processes with improved accuracy, in both acidic and basic environments, which has potent applications in biochemical analysis and point-of-care testing.

Halogen‐Driven Single‐Crystal to Single‐Crystal Transformation Engineering the Cluster‐based Spin Crossover Frameworks

AbstractCluster‐based spin crossover (SCO) frameworks are a new class of smart metal–organic frameworks (MOFs) with diverse structures and topologies and unique bistable physicochemical properties. Here, we report a cluster‐based SCO framework [Fe3{Ag4(CN)6(H2O)}2(TPBA)3](ClO4)2 ⋅ 7DMF (1) with an extremely rare 3,4,6‐T108 topology, in which the tripodal [Ag{Ag(CN)2}3(H2O)]2− clusters axially link the Fe2+ ions to form 2D→3D n‐fold Borromean entangled networks. Under the guidance of reticular chemistry, the post‐synthetic modification (PSM) from 1 with 3,4,6‐T108 topology to [Fe3{Ag8X8(CN)6}(TPBA)3] (2_X, X=Cl, Br, I) with urk topology is firstly achieved via single‐crystal to single‐crystal (SCSC) transformation. Moreover, the successive SCSC transformations from 2_Cl to 2_Br and then to 2_I are realized for the first time. Their SCO behaviors are also modified by halogen‐driven stepwise cluster transformations. Hence, these findings provide new strategies for the development of cluster‐based SCO MOFs towards the smart functional porous materials.

Low Power Gas Sensors: From Structure to Application.

Gas sensors are pivotal across industries, encompassing environmental monitoring, industrial safety, and healthcare. Recently, a surge in demand for low power gas sensors has emerged, driven by the huge need for applications in portable devices, wireless sensor networks, and the Internet of things (IoT). The practical realization of a densely interconnected sensor network demands gas sensors to have low power consumption for energy-efficient operation. This Perspective offers a comprehensive overview of the progress of low-power sensors for gas and volatile organic compound detection, with a keen focus on the interplay between sensing materials (including metal oxide semiconductors, metal-organic frameworks, and two-dimensional materials), sensor structures, and power consumption. The main gas sensing mechanisms are discussed, and we delve into the mechanisms for achieving low power consumption including material properties and sensor design. Furthermore, typical applications of low power gas sensors are also presented, including wearable technology, food safety, and environmental monitoring. The review will end by discussing some open questions and ongoing needs.

High-intensive aerogels constructed through in-situ growth of ZIF-8-NH2 on wood for efficient formaldehyde absorption

Metal-organic frameworks (MOFs) are highly advantageous due to their tunable pore size, exceptional thermal and chemical stability, and high specific surface area, making them ideal for applications in formaldehyde adsorption. However, the practical use of powdered MOFs is significantly hindered by their recycling challenges. In this research, wood-based composite aerogels (WAZN-X) were successfully prepared through loading Zeolitic Imidazolate Framework-8-NH2 (ZIF-8-NH2) inside wood aerogels. Ascribing to the elimination of lignin and hemicellulose, the enlarged pore structures of wood aerogels and the potential interactions (e.g., hydrogen bonding and electrostatic attractions) between components promoted the uniformly depositing of ZIF-8-NH2 nanocrystals. The WAZN-X aerogels displayed excellent mechanical strength (e.g., the longitudinal Young’s modulus of 68.57 MPa) and promising formaldehyde adsorption performance (e.g., a stable formaldehyde removal rate of 98.11 %), and kept commendable reusability (95.98 % after 5 cycles). This research provides a new insight for developing high-value functional composite adsorbents for efficient formaldehyde purification.

Dual Signature of Chirality Induced Spin Selectivity through Spontaneous Resolution of 2D Metal-Organic Frameworks.

The Chiral-Induced Spin Selectivity (CISS) effect has emerged as a fascinating phenomenon within the realm of electron's spin manipulation, showcasing a unique interplay between electron's spin and molecular chirality. Subsequent to its discovery, researchers have been actively involved in exploring the new chiral molecules as effective spin filters. In the realm of observing the CISS effect, the conventional approach has mandated the utilization of two distinct enantiomers of chiral molecules. However, this present study represents a significant advancement by demonstrating the ability to control both spin states of electrons in a single system. In this work, we have demonstrated the preparation of chiral metal-organic frameworks (MOFs) via a "spontaneous resolution" process, obviating the requirement for chiral sources. This resulted in the production of chiral crystals exhibiting opposite handedness (1P and 1M) and these crystals were subsequently employed as a new class of spin filters based on CISS effect. Remarkably, this work signifies the first instance of achieving dual signature of spin selectivity from a single and exclusively achiral system through a spontaneous resolution process. This holds immense potential as it facilitates the production of two distinct spin-filtering materials from a unified system. Furthermore, we investigated the contact potential differences (CPD) of these chiral crystals and, for the first time, associated it with the preferential spin transport properties. Our findings revealed a correlation between the CPD and the chirality of the crystals, as well as the magnetization orientations of the ferromagnetic substrate, which can be elucidated by the CISS effect. In overall, the significant findings achieved using these robust and easily synthesized MOF crystals without the requirement for chiral medium represent a crucial advancement in enhancing the effectiveness of spin filtering materials to produce spintronic devices.

Application and performance Enhancement of acetic acid-Regulated ligand defect engineering in NiMOF electrocatalysts

Introducing organic ligands into metal-organic frameworks (MOFs) is an effective method for preparing defective MOFs. This approach enables the fabrication of cost-effective, efficient, highly conductive, and richly active-site electrocatalysts. Herein, the defective NiMOF is synthesized via a straightforward one-pot solvothermal method by partially substituting phthalic acid (PTA) ligands with acetic acid (HOAc), which effectively regulates the micro-morphology and electronic structure of the NiMOF nanoflowers, thus creating abundant electrochemical active sites, significantly improving electronic conductivity and promoting rapid charge transfer. The resulting DE-NiMOF-0.5 nanoflowers, prepared with HOAc substitution, demonstrate excellent electrochemical performance at a current density of 10 mA cm−2, the hydrogen evolution reaction (HER) overpotential is 188 mV (Tafel slope of 175 mV dec−1), while the oxygen evolution reaction (OER) overpotential is 205 mV (Tafel slope of 37 mV dec−1). The introduction of acetic acid ligands in DE-NiMOF-0.5 not only constructs the ligand defects within the catalyst, but also increases the abundant active sites, enhancing the hydrophilicity of the catalyst and facilitating electronic transfer between the catalyst surface and the electrolyte. This study explores a strategy for preparing defective MOF catalysts through introducing modulators, providing an economically viable material pathway for electrocatalysis and opening new possibilities for designing and synthesizing efficient electrocatalysts in future research endeavors.

Structural Characteristics and DNA Groove Binding Abilities of Two Zinc-Based Isoreticular MOFs.

In this study, we have synthesized two zinc(II)-based metal-organic frameworks (MOFs) designated as [Zn(4-nvp)(bdc)] ⋅ (MeOH) (1) and [Zn2(4-nvp)2(bpdc)2] ⋅ (DMF) (2) [4-nvp=4-(1-naphthylvinyl) pyridine, H2bdc=1,4-benzendicarboxylic acid and H2bpdc=4,4'-biphenyldicarboxylic acid]. Single-crystal X-ray diffraction (SCXRD) of both compounds unveiled an interesting paddle-wheel [Zn2(O2C-C)4] secondary building block (SBB) composed of dinuclear Zn (II) centers and four dicarboxylate groups with a (4,4) square grid topology. These SBBs are interconnected giving rise to an infinite 2D layer architecture. Notably, the grid structure is composed of MeOH molecules in compound 1 and DMF molecules in compound 2, both of them arranged in a free lattice. In both compounds, 3D supramolecular architecture is ultimately formed through the stacking of 2D layers. Since the length of the bpdc ligand is higher than that of the bdc ligand, the solvent-accessible void volume is comparatively higher for compound 2. To corroborate all non-bonded interactions, Hirshfeld analysis was carried out for synthesized compounds. DNA binding application was extensively investigated through docking study. Results indicated that the synthesized compounds have strong affinities towards DNA via DNA groove binding. Henceforth, the synthesized compounds 1 and 2 would open the door for their potential applications as particular protein binders and bioactive substances.

Halogen-Driven Single-Crystal to Single-Crystal Transformation Engineering the Cluster-based Spin Crossover Frameworks.

Cluster-based spin crossover (SCO) frameworks are a new class of smart metal-organic frameworks (MOFs) with diverse structures and topologies and unique bistable physicochemical properties. Here, we report a cluster-based SCO framework [Fe3{Ag4(CN)6(H2O)}2(TPBA)3](ClO4)2 ⋅ 7DMF (1) with an extremely rare 3,4,6-T108 topology, in which the tripodal [Ag{Ag(CN)2}3(H2O)]2- clusters axially link the Fe2+ ions to form 2D→3D n-fold Borromean entangled networks. Under the guidance of reticular chemistry, the post-synthetic modification (PSM) from 1 with 3,4,6-T108 topology to [Fe3{Ag8X8(CN)6}(TPBA)3] (2_X, X=Cl, Br, I) with urk topology is firstly achieved via single-crystal to single-crystal (SCSC) transformation. Moreover, the successive SCSC transformations from 2_Cl to 2_Br and then to 2_I are realized for the first time. Their SCO behaviors are also modified by halogen-driven stepwise cluster transformations. Hence, these findings provide new strategies for the development of cluster-based SCO MOFs towards the smart functional porous materials.

Enhanced Electrocatalytic Capacity of Two POM@NH2‐MIL‐101(Fe) Composites for Oxygen Evolution Reaction

AbstractThe development and exploration of efficient bifunctional electrocatalysts for water splitting are in high demand and have garnered significant attention in recent years. Herein, by incorporating the advantages of catalytically active polyoxometalates (POMs) and structural stable metal–organic frameworks (MOFs), two POM@MOFs composite materials, Ni4Mo12@Fe and Co4Mo12@Fe, have been successfully prepared via the encapsulation of POMs anions, [MoV12O30(μ2‐OH)10H2{NiII4(H2O)12}]∙14H2O (noted as Ni4Mo12) and [MoV12O30(μ2‐OH)10 H2{CoII(H2O)3}4]∙12H2O (noted as Co4Mo12), into the cavities of MOFs NH2‐MIL‐101(Fe), respectively. Compared to each individual components, Ni4Mo12@Fe and Co4Mo12@Fe composites, as heterogeneous electrocatalysts, both showed enhanced electrocatalytic capacities for efficient oxygen evolution reaction (OER) under alkaline conditions with overpotentials of 332.64 mV for Ni4Mo12@Fe and 352.64 mV for Co4Mo12@Fe at 10 mA cm−2. Additionally, the enhanced electrocatalytic capacities of these two composites could also achieve towards hydrogen evolution reaction (HER). Such a POMs‐assisted strategy for the formation of POM@MOFs composites, described here, paves a new avenue for the development of highly economical, active nonnoble metal bifunctional electrocatalysts for OER and HER.

Dual-doped metalloporphyrin MOFs-based nanoagent increases low-dose radiotherapy efficacy by apoptosis-ferroptosis for hepatocellular carcinoma

Radiotherapy (RT) represents a cornerstone therapeutic approach in clinical practice for locally control of hepatocellular carcinoma (HCC). However, its efficacy in treating liver cancer is significantly hampered by radiation resistance, which attributed to the insufficient reactive oxygen species (ROS) generation within the tumor microenvironment (TME). To augment RT efficacy, we have developed a novel radiosensitizer termed PTFM. The compound has the features of meso-tetra (4-carboxyphenyl) porphine (TCPP) porphyrin metal–organic frameworks (MOF, PCN-224(Fe)) co-doped with high-atomic element Ta. Under X-ray excitation, the porous PTFM acts as a proficient radio-sensitization, absorbs X-ray energy to promote hydroxyl radicals generation for RT, thereby disrupting the redox balance and intensifying the cytotoxic effect on tumor cells. The incorporation of Fe3+ into the macrocycle of TCPP within the MOFs shell, facilitates the reactions with GSH and H2O2 in the TME, leads to ROS production that promotes ferroptosis and apoptosis, while also releases O2 to alleviate tumor hypoxia. Furthermore, PTFM with thermo-metal serves as a dual-mode MR/CT imaging contrast agent, enabling precise RT monitoring and imaging guidance. In conclusion, the radiosensitizer we developed integrates dual-mode imaging capabilities and enhances RT sensitization for HCC through ROS-induced cell apoptosis and ferroptosis, thereby ameliorating tumor hypoxia.

Enhancing ethanol/water separation in UTSA-280 by a pore engineering strategy

Dehydration of ethanol is the key issue for the production of bioethanol fuel. Based on energy-efficient water-adsorptive mechanism and size sieving effect of ultramicroporous metal–organic framework, UTSA-280 is a promising candidate for high purity ethanol production. But it is still a challenge to improve the water adsorption capacity of UTSA-280 without compromising the separation selectivity. Here, we present a post-synthetic pore engineering strategy towards coordinated water adjustment for UTSA-280 to address this challenge. Partial coordinated water molecules have been successfully removed in UTSA-280·xPCW. By reversible desorption and resorption of water to Ca ions, the saturated water adsorption of UTSA-280·xPCW increased up to 2.6 mol/mol (exceeding 60 % that of original UTSA-280). The enhancing effect were supported by both kinetics and thermodynamics mechanisms. Dynamic vapor breakthrough results showed that UTSA-280·41PCW produced the largest amount of pure ethanol (22.46 mmol/g) and highest water/ethanol separation factor (15.9), providing a synchronized enhancement of water adsorption and ethanol/water separation. UTSA-280·xPCW are promising candidates for the dehydration of ethanol.

Polymer‐Assisted Nucleation for Stable Single‐Crystal Perovskite Thin Films

AbstractOrganic‐inorganic hybrid perovskite single crystals have emerged as a strong candidate in photovoltaic and general optoelectronic applications. However, the high supersaturation of the precursor solution leads to the rapid formation of a significant number of nuclei and a diminished concentration of perovskite solute. Consequently, the inadequate availability of precursors poses challenges in sustaining the subsequent crystal growth phase, culminating in the development of small‐sized single crystals. In this work, we report a controlled nucleation process to foster the growth of large‐size single crystals. This method through the coordination interaction between polyacrylic acid and Pb2+ ions, and substitution of the coordination with I− ions. This reduces the formation of the Pb‐I6 complex, which promptly emerges in a state of supersaturation and acts as a nucleus, thereby effectively reducing the number of nuclei formed. The single crystals produced using this method exhibit a lateral size exceeding 5 mm, an extended absorption range, a longer carrier lifetime of 10.93 ns, and enhanced stability. These crystals demonstrate the ability to remain stable even after storage in an ambient environment (T=20±5 °C, RH=60±5 %) for a period of 20 days.

Amino-Functionalized Metal-Organic Framework-Mediated Cellulose Aerogels for Efficient Cr(VI) Reduction.

Industrialization activities have increased the discharge of wastewater that is polluted with hexavalent chromium (Cr(VI)), posing risks to ecosystems and humans. The photocatalytic reduction of Cr(VI) is viewed as a promising method for the removal of Cr(VI) species. However, developing photocatalysts with the desired catalytic activity, recyclability, and reusability remains a challenge. Herein, a composite aerogel was designed and fabricated with a Ti-based metal-organic framework (MIL-125-NH2) and carboxylated nanocellulose. MIL-125-NH2 presents a strong visible-light response, and the interactions between the amino groups of MIL-125-NH2 and the carboxyl groups of cellulose produce a strong interface affinity in the composites. The as-prepared aerogels exhibited a micro/macroporous structure. At an optimal MIL-125-NH2 loading of 55 wt%, the MC-5 sample showed a specific surface area of 582 m2·g-1. MC-5 achieved a photocatalytic Cr(VI) removal efficiency of 99.8%. Meanwhile, the aerogel-type photocatalysts demonstrated good stability and recycling ability, as MC-5 maintained a removal rate of 82% after 10 cycles. This work sheds light on the preparation of novel photocatalysts with three-dimensional structures for environmental remediation.