Multifunctional Metal-organic Frameworks Research Articles

Construction of two isomorphic multifunctional MOFs via a dual-ligand strategy for aromatic compounds detection and photocatalytic degradation performance

The development of multifunctional and structurally unique metal−organic frameworks (MOFs) presents a highly attractive yet challenging endeavor for chemists. In this study, we employ a dual-ligand strategy to synthesize two isomorphic Co/Zn MOFs, {[Co4(BMIP)3(MIP)4]·3DMF·H2O}n (SNUT-35-Co) and {[Zn4(BMIP)3(MIP)4]·2DMF·2H2O}n (SNUT-35-Zn). The photocatalytic performance of SNUT-35-Co and SNUT-35-Zn was evaluated using methylene blue (MB). Under UV/visible-light irradiation, the photocatalytic decolorization rates of MB for SNUT-35-Co and SNUT-35-Zn reached 95% within 140 min and 120 min, respectively, indicating their superior degradation. Notably, SNUT-35-Zn demonstrated exceptional detection capabilities for aromatic compounds, such as aniline and nitrobenzene, at lower concentration range without interference from other components. The detection limits for these two small molecules were found to be 0.430 and 0.431 μM, respectively. Additionally, both MOFs exhibited larger transient photocurrents and lower impedance in electrochemical measurements. The results suggested that the photocatalytic activities of MOF are influenced by their three-dimensional structures, which facilitate electrons passing due to the inherent semiconductor properties.

Molecular Architecture @ MOFs: Designing a Multifunctional Catalyst for the Cascade Reaction of Olefins via Epoxides to Cyclic Carbonates

Employing enzymatic reaction cascade principles to synthesize artificial materials with multiple autonomously operating active sites is one of the holy grails in modern catalysis research. In this regard, metal‐organic frameworks (MOFs) are promising host platforms. Yet, applying MOFs as enzyme‐mimicking catalysts is synthetically challenging. Herein, we present a design strategy for the synthesis of porphyrin‐based MOFs for the cascade catalysis of the conversion of olefins to epoxides and their cycloaddition with CO2 to cyclic carbonates. The MOFs feature tunable dual active sites with synthetically controllable metal variations. A clear dependence of the metal combination on the catalytic performance of the MOF catalysts is shown. This work advances the understanding essential for designing sophisticated, multifunctional porphyrin MOFs for efficient one‐pot cascade catalysis.

A porous three-dimensional Cu-MOF: Preparation and application in supercapacitors, low temperature hydrogen storage and gas separation

Due to its unique porosity, metal–organic frameworks (MOFs) have great application prospects in the fields of gas adsorption and separation. However, the synthesis of multi-functional MOFs is still a great challenge. Herein, a multi-functional Cu-MOF of {[Cu2(TPTA)(H2O)2]·2DMF·NMP·4H2O}n with a porosity of 62.0 % was designed and synthesized. The H2 adsorption amount of Cu-MOF is about 289.2 cm3 g−1 at 77 K and 1 bar. Meanwhile, the selectivity adsorption of Cu-MOF towards CO2 over CH4 (V:V = 0.5:0.5), CO2/N2 (V:V = 0.5:0.5) and CO2/H2 (V:V = 0.5:0.5) is 95.1, 139.2 and 147.5, respectively, which is 1.5 times higher than the previously reported Cu-MOFs. The Cu-MOF@NF//AC asymmetric supercapacitor demonstrates high specific capacitance (53.4 F g−1) and stability (90.3 % after 2000 cycles). Furthermore, this work presents a novel approach to design multifunctional materials with low temperature hydrogen storage, gas separation and energy storage properties.

Multifunctional Ni-MOF (3D) with N-rich structures for self-generated reactive oxygen species and enhanced electron transfer for synergistic degradation of organic pollutants and removal of Hg(II)

Metal–organic frameworks (MOFs) can effectively adsorb or remove pollutants; however, their application to water treatment remains limited. Herein, we report the preparation of two novel multifunctional Ni-based MOFs (2D and 3D), via the design and synthesis of multi-nitrogen-like ligands. The introduction of polynitrogen-containing organic macrocyclic ligands improved the structure and electron transfer capability of the MOF, and its adsorption and synergistic degradation performance were further enhanced via coordination with Ni. The 3D MOF (MOF-2) had a maximum adsorption capacity of 948 mg/g for Hg(II). The adsorption and synergistic degradation capacities of MOF-2 for tetracycline (TC, 18 mg/L), 17α-ethynylestradiol (EE2, 3 mg/L), rhodamine B (RhB, 6 mg/L), and methylene blue (MB, 6 mg/L) were 98.54%, 97.32%, 91.08%, and 85.02%, respectively. The addition of KHSO5 (PMS, 0.01 g/L) resulted in nearly 100% degradation of the organic pollutants within 100 min. MOF-2 alone simultaneously degraded more than 90.73% (360 min Hg(II) adsorption equilibrium) of five pollutants in ultrapure water, tap water, and lake water. MOF-2+PMS degraded 99.13% of TC within 60 min, and the remaining four pollutants were completely adsorbed and degraded. DFT calculations and experiments indicated that the efficient adsorption of Hg(II) and efficient degradation of the organic pollutants by MOF-2 were mainly attributed to its abundant N atoms, which provide active sites for Hg(II) capture; and the structure itself has strong electron transfer ability and self-produced reactive oxygen species (ROS), which can effectively degrade organic pollutants and activate PMS to enhance the degradation efficiency. MOF-2 also exhibited 100% antibacterial activity against Escherichia coli and Staphylococcus aureus. This work provides a basis for designing synthesis pathways for MOFs and elucidates the electron-transfer mechanism underlying the enhanced synergistic removal of complex pollutants from water.

Aggregation-induced emission-based competitive immunoassays for “signal-on” detection of proteins with multifunctional metal–organic frameworks as signal tags

An aggregation-induced emission (AIE)-based strategy was proposed for fluorescence immunoassays of protein biomarkers using Cu-based metal–organic frameworks (Cu-MOFs) to load recombinant targets and enzymes for dual signal amplification. The immunosensing platform was built based on the sequestration and consumption of the substrates of pyrophosphate (PPi) ions by Cu-MOFs and enzymatic catalysis. The negatively charged PPi could trigger the aggregation of positively charged tetraphenylethene (TPE)-substituted pyridinium salt nanoparticles (TPE-Py NPs) by electrostatic interactions, lighting up the fluorescence due to the AIE phenomenon. The consumption of PPi by the captured Cu-MOFs through the Cu2+-PPi chelation interaction and ALP–enzymatic hydrolysis depressed the aggregation of TPE-Py NPs. Capture of the tested targets in samples by the antibodies on the plate surface could prevent the attachment of target/ALP-loaded Cu-MOFs due to the competitive immunoreactions. The “signal-on” competitive immunoassay was applied for the detection of procalcitonin (PCT) as the model analyte with a linear range of 0.01–10 pg/mL and a detection limit down to 8 pg/mL. The conceptual integration of AIE with enzymatic and MOFs–based dual signal amplification endowed fluorescence immunoassays with high sensitivity and selectivity. The surface modification of Cu-MOFs with hexahistine (His6)-tagged recombinant proteins through metal coordination interactions should be evaluable for the design of novel biosensors.

Evaluating the effect of different ligands on the supercapacitance and hydrogen evolution reaction studies of Zn-Co MOF

Metal-Organic Frameworks (MOFs) have recently attracted a lot of interest because of their potential uses in energy storage and catalysis. In this study, we investigate the impact of various ligands on the electrochemical performance of Zn-Co MOFs for both energy storage and hydrogen evolution reaction (HER) studies. Specifically, Zn-Co MOFs are synthesized using different ligands, and their structural and electrochemical properties are characterized by a range of analytical techniques. 2,5-dihydroxybenzoic acid (DBA) and benzene-1,2,4,5-tetracarboxylic acid (BTC) are employed due to their distinct structural features and potential effects on MOF performance. Subsequently, electrochemical studies are conducted to assess the supercapattery performance and HER activity of these MOFs. The specific capacitance and overpotential value at 10 mA/cm2 of Zn-Co/DBA MOF is observed to be 1775.3 F/g and 186 mV, whereas that of Zn-Co/BTC MOF is found to be 136.6 F/g and 279 mV. The MOF synthesis using DBA as a ligand is more effective for energy-related applications. This study aims to report a multifunctional MOF composite for energy and environmental applications with better efficiency than other reported systems. Our findings provide insights into how the choice of ligand influences the structural properties and electrochemical behavior of Zn-Co MOFs, shedding light on the potential of these MOFs as versatile materials for energy storage and HER applications.

Combining electron transfer, spin crossover, and redox properties in metal-organic frameworks

Hofmann coordination polymers (CPs) that couple the well-studied spin transition of the FeII central ion with electron-responsive ligands provide an innovative strategy toward multifunctional metal-organic frameworks (MOFs). Here, we developed a 2D planar network consisting of metal-cyanide-metal sheets in an unusual coordination mode, brought about by infinitely π-stacked redox-active bipyridinium derivatives as axial ligands. The obtained family of materials show vivid thermochromism attributed to electron transfer and/or electronic spin state change processes that can occur either independently or concomitantly. Importantly, the redox activity of the ligands within the structure leads to the quasi-reversible electrochemical reduction reaction on a spin-crossover complex at solid state. These observations have been confirmed via temperature-dependent single-crystal X-ray diffraction, magnetic measurements, Mössbauer, EPR, optical and vibrational spectroscopies as well as quantum chemical calculations.

One-Pot Preparation of Nitro-Functionalized Bimetallic UiO-66(Zr-Hf) with Hierarchical Porosity for Oxidative Desulfurization Performance.

Preparation of multifunctional metal-organic frameworks (MOFs) offers new opportunities to obtain ultrahigh synergistic catalytic performance for heterogeneous reactions; however, the application of a one-pot method for preparing multifunctional MOFs remains challenging. Herein, we develop a one-pot green route for synthesizing bimetallic nitro-functionalized UiO-66(Zr-Hf)-NO2 with hierarchical porosity under solvent-free conditions. The optimal UiO-66(Zr-Hf0.6)-NO2 shows an ultrahigh enhancement of oxidative desulfurization (ODS) efficiency to oxidize sulfur compounds (1000 ppm sulfur) in a model fuel at 40 °C within 12 min due to the introduction of more active Hf sites in the nodes, the increased Lewis acidity of Zr/Hf-O nodes by the electron-withdrawing NO2 group, and the enhanced diffusion rates by the mesopores. The turnover frequency (TOF) over UiO-66(Zr-Hf0.6)-NO2 at 40 or 50 °C reaches 145.3 or 217.0 h-1 that surpasses the TOF of most reported MOF-based catalysts in the ODS reaction. Quenching and electron paramagnetic resonance experiments confirm that the formed Hf-OH on the Zr/Hf-O nodes can easily decompose the oxidant (H2O2) for generating a Hf-OOH-active intermediate and dominate the ODS efficiency. This contribution provides a one-pot solvent-free avenue to synthesize multifunctional MOFs for enhancing their catalytic activities for targeted applications.

Zn-based metal–organic framework for detection and ultra-adsorption of Fe3+ ion and catalytic degradation of methylene blue

Metal-organic frameworks (MOFs) had shown a wide range of application prospects in the removal of pollutants in water because of its designability. In this work, a multifunctional MOF material (S-MOF) had been designed by selecting ligand in advance and introducing specific groups in synthesis process. The S-MOF showed excellent stability. S-MOF could specifically identify Fe3+ ion in water and can selectively remove (442 mg/g) them ultra-efficiently (>99.9 %). Moreover, it can stably identify and remove Fe3+ ion in complex water where many ions exist. It was worth emphasizing that the adsorbed waste (Fe@S-MOF) of S-MOF was also recovered and its properties were studied. Fe@S-MOF exhibited highly efficient catalytic degradation of methylene blue, which could degrade more than 98.7 % of methylene blue, and its pseudo-first-order rate constant was as high as 0.829 min−1. Moreover, the successful preparation of S-MOF and Fe@S-MOF membrane had also simplified the recovery and expanded its application. In general, not only a multi-functional MOF material with application potential had been obtained, but also its recycling promoted the green and sustainable development of MOFs and broadened the road of MOFs materials in development and application.

Separable Metal-Organic Framework-Based Materials for the Adsorption of Emerging Contaminants.

Thousands of chemicals have been released into the environment in recent decades. The presence of emerging contaminants (ECs) in water has emerged as a pressing concern. Adsorption is a viable solution for the removal of ECs. Metal-organic frameworks (MOFs) have shown great potential as efficient adsorbents, but their dispersed powder form limits their practical applications. Recently, researchers have developed various separable MOF-based adsorbents to improve their recyclability. The purpose of this review is to summarize the latest developments in the construction of separable MOF-based adsorbents and their applications in adsorbing ECs. The construction strategies for separable MOFs are classified into four categories: magnetic MOFs, MOF-fiber composites, MOF gels, and binder-assisted shaping. Typical emerging contaminants include pesticides, pharmaceuticals and personal care products, and endocrine-disrupting compounds. The adsorption performance of different materials is evaluated based on the results of static and dynamic adsorption experiments. Additionally, the regeneration methods of MOF-based adsorbents are discussed in detail to facilitate effective recycling and reuse. Finally, challenges and potential future research opportunities are proposed, including reducing performance losses during the shaping process, developing assessment systems based on dynamic purification and real polluted water, optimizing regeneration methods, designing multifunctional MOFs, and low-cost, large-scale synthesis of MOFs.

Highly sensitive and selective electrochemical detection of Aflatoxin B1 in water and Pistachio samples with MOF/MXene composite based sensor

Aflatoxins are poisonous secondary metabolites capable of causing toxicity in several food items and water. The routine monitoring of Aflatoxins has assumed great analytical significance. The electrochemical biosensors are attractive tools to screen the Aflatoxin-laden samples. The present study reports on a new type of electrochemical biosensor, based on an electrode prepared of multifunctional MOF (Metal-organic framework)/MXene composite material. Molybdenum-based 2-dimensional (2D) MOF and Ti3C2 MXene have been mixed to prepare the composite, which is then deposited over a screen-printed electrode (SPE). The anti-Aflatoxin B1 (AFB1) antibodies (Ab) are covalently complexed, and the prepared Ab-MOF/MXene sensor is investigated for its applicability to detect AFB1. Utilizing the electrochemical impedance spectroscopic (EIS) analysis, the Ab-MOF/MXene sensor has allowed the detection of AFB1 from 0.06 to 50 ng/mL with a very low limit of detection, i.e., 8 pg/mL. The sensor performs well with respect to all the major quality parameters, such as long-term stability, specificity in co-presence of interfering species, reproducibility, and repeatability. It is demonstrated successfully to detect AFB1 in the spiked samples of Pistachio.

A Highly Stable Multifunctional Bi-Based MOF for Rapid Visual Detection of S2- and H2S Gas with High Proton Conductivity.

Metal organic frameworks (MOFs) constructed with bismuth metal have not been widely reported, especially multifunctional Bi-MOFs. Therefore, developing multifunctional MOFs is of great significance due to the increasing requirements of materials. In this work, a 3D Bi-MOF (Bi-TCPE) with multifunctionality was successfully constructed, demonstrating high thermal stability, water stability, a porous structure, and strong blue fluorescence emission. We evaluated the properties of Bi-TCPE in detecting anions (S2-, Cr2O72-, and CrO42-) in aqueous solution, along with the rapid visual detection of H2S gas and proton conduction. In terms of anion detection, Bi-TCPE achieved the rapid detection of trace S2- in aqueous solutions, while the Ksv value was 1.224 × 104 M-1 with a limit of detection (LOD) value of 1.93 μM through titration experiments. Furthermore, Bi-TCPE could sensitively detect Cr2O72- and CrO42-, with Ksv values of 1.144 × 104 and 1.066 × 104 M-1, respectively, while LOD reached 2.07 and 2.18 μM. Subsequently, we conducted H2S gas detection experiments, and the results indicated that Bi-TCPE could selectively detect H2S gas at extremely low concentrations (2.08 ppm) and with a fast response time (<10 s). We also observed significant color changes under both UV light and sunlight. Therefore, we developed a H2S detection test paper for the rapid visual detection of H2S gas. Finally, we evaluated the proton conductivity of Bi-TCPE, and the experimental results showed that the proton conductivity of Bi-TCPE reached 4.77 × 10-2 S·cm-1 at 98% RH and 90 °C, achieving an excellent value for unmodified and encapsulated MOFs. In addition, Bi-TCPE showed high stability in proton conduction experiments (it remained stable after 21 consecutive days of testing and 12 cycles of testing), demonstrating relatively high application value. These results indicate that Bi-TCPE is a multifunctional MOF material with great application potential.

Multifunctional Metal-Organic Frameworks Driven Three-Dimensional Folded Paper-Based Microfluidic Analysis Device for Chlorpyrifos Detection.

Chlorpyrifos (CPF) residues in food pose a serious threat to ecosystems and human health. Herein, we propose a three-dimensional folded paper-based microfluidic analysis device (3D-μPAD) based on multifunctional metal-organic frameworks, which can achieve rapid quantitative detection of CPF by fluorescence-colorimetric dual-mode readout. Upconversion nanomaterials were first coupled with a bimetal organic framework possessing peroxidase activity to create a fluorescence-quenched nanoprobe. After that, the 3D-μPAD was finished by loading the nanoprobe onto the paper-based detection zone and spraying it with a color-developing solution. With CPF present, the fluorescence intensity of the detection zone gradually recovers, the color changes from colorless to blue. This showed a good linear relationship with the concentration of CPF, and the limits of detection were 0.028 (fluorescence) and 0.043 (colorimetric) ng/mL, respectively. Moreover, the 3D-μPAD was well applied in detecting real samples with no significant difference compared with the high-performance liquid chromatography method. We believe it has huge potential for application in the on-site detection of food hazardous substance residues.

Active Site Isolation and Enhanced Electron Transfer Facilitate Photocatalytic CO2 Reduction by A Multifunctional Metal–Organic Framework

Active Site Isolation and Enhanced Electron Transfer Facilitate Photocatalytic CO₂ Reduction by A Multifunctional Metal–Organic Framework

Recycling waste plastic to construct ultra-stable and multifunctional metal-organic framework for fast efficient dye adsorption and acetone vapor detection

Plastic pollution and water pollution are currently two major environmental problems. Exploring a strategy that can convert waste plastics into high value-added functional materials will be an effective solution to relieve above issues. Herein, we realized that the waste plastic of polyethylene terephthalate (PET) was converted into ultra-stable and multifunctional 3D pillared-layer Eu-based metal-organic framework (MOF) material (labelled as Eu-PET) through one-pot solvothermal method. The effects of reaction conditions on the waste plastic PET upcycling were explored in detail. The Eu-PET exhibits excellent Congo red (CR; Concentration: 1 g/L) adsorption capacity of 2312 mg/g in 2 h at nature pH (2988.11 mg/g at pH = 4). Moreover, the influence parameters containing dye concentration, adsorbent dosage, pH, temperature and simulated dye wastewater were studied. The adsorption mechanism was explained by pseudo-second order and Langmuir models, revealing the adsorption of CR on Eu-PET was mainly defined by electrostatic interaction, hydrogen bonding interaction and π-π interaction. Furthermore, Eu-PET as fluorescent sensor, a portable Eu-PET fluorescent film was developed. Experiments have shown that a noticeable fluorescent quenching response occurred within 10 s contact to acetone vapor, and the theoretically detectable limit (LOD) was as low as 0.048 % (v/v), and Eu-PET/acetone system was static quenching. Finally, Eu-PET has excellent water, acid-base and thermal stability, and recyclability over 7 cycles of CR adsorption and acetone detection. This work opens an avenue for the green recycling/utilization of plastic waste, providing meaningful insights into the effective processing of dyes wastewater and fluorescence sensing of volatile organic compounds.

A novel treatment modality for rheumatoid arthritis: Inflammation-targeted multifunctional metal-organic frameworks with synergistic phototherapy and chemotherapy

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease with complex pathogenesis. Single chemotherapy struggles to eliminate the disease permanently and reduce the pain owing to drug resistance and inadequate delivery to target cells. This study developed hyaluronic acid (HA)-modified and methotrexate (MTX)-load metal-organic frameworks (denoted as FT-HA-MTX NPs), combining photothermal therapy (PTT), photodynamic therapy (PDT), and chemotherapy to inhibit the progression of RA. In vitro experiments proved that the obtained NPs exhibited good biocompatibility and commendable photothermal conversion efficiency of 36.3 %. Additionally, they promoted ∙OH and O2 production via the Fenton reaction, which dramatically alleviated hypoxia and enhanced ROS generation, and induced substantial mortality in activated RAW 264.7 cells, with cell viability of 31.72 %. Cellular uptake and in vivo imaging confirmed that the modification of HA enabled the NPs to specifically target activated macrophage, ensured prolonged retention of NPs in inflamed synovial tissues, and reduced systemic toxicity. In vivo, after FT-HA-MTX NPs treatment with laser irradiation, the levels of TNF-α and IL-1β in the synovial tissue were reduced by approximately 50 % compared to those in the inflamed synovium, demonstrating a significant enhancement in the anti-inflammatory effect (p < 0.001). In conclusion, FT-HA-MTX NPs are promising inflammation-targeted multifunctional nanoparticles that combine PTT, PDT, and chemotherapy, thereby significantly inhibiting the progression of RA while reducing systemic toxicity.

A Multimode Optical Sensor for Selective and Sensitive Detection of Harmful Heavy Metal Cr(VI) in Fresh Water and Sea Water.

Water pollution originating from heavy metals has shown great impacts on the ecological environment and human health due to their extremely low biodegradability. Hexavalent chromium Cr(VI), as one harmful heavy metal with strong oxidation, high biological permeability, and high carcinogenicity, is becoming an increasingly serious threat to human health. Therefore, conveniently but accurately, monitoring the Cr(VI) level in water to maintain its normal level and ensuring the stability of the ecosystem and human health become very valuable. However, most of these heavy metal sensors reported are turn-off type single-emission sensors. In this work, a ratiometric fluorescence/colorimetry/smartphone triple-mode turn-on optical sensor for Cr(VI) was developed based on a multifunctional metal-organic framework platform. The detection limits for these three mutual verification modes were only 1.28, 4.89, and 68.4 nM, respectively. Additionally, the color changes of the detection system under sunlight can also be observed directly by the naked eye. The accuracy and practicability of this multimode sensor were further proved by the detection of Cr(VI) in actual water and seawater samples, and the recovery rate ranged from 97.308 to 104.041%.

Multifunctional hydrophobic MOFs modified by rosin acid with oil–water separation and room temperature catalysis

Metal-organic frameworks (MOFs) are high surface area porous materials with uniform pores. MOFs are among the widely investigated porous materials because of their potential applications in adsorption, oil–water separation, catalysis, and other such applications. However, MOFs are not stable enough in aqueous environments, which restricts their application in practice. We converted hydrophilic UiO-66-SH into hydrophobic UiO-66-RA by introducing rosin acid into organic linkers. The material was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The superhydrophobic UiO-66-RA was successfully constructed and the water droplet contacts angle reached 157.2°. Importantly, the obtained UiO-66-RA demonstrated stable oil–water separation performance, with separation efficiencies of up to 96.1% and 96.8% for both light and heavy oils. The separation efficiencies also reached more than 95.1% after five repetitions. For stable oil–water emulsions, UiO-66-RA also achieved effective separation. In addition, the catalyst Pd@UiO-66-RA was successfully prepared by hybridization of palladium chloride with UiO-66-RA. The catalytic yields of Pd@UiO-66-RA was 95.4%. And the yield could also be kept above 60% after five cycles of Sonogashira reaction catalyzed. This work offers a new type of superhydrophobic MOFs, the multifunctional MOFs has the potential for environmentally benign catalysis and purification of wastewater.

Solar Gas-Phase CO2 Hydrogenation by Multifunctional UiO-66 Photocatalysts.

Solar-assisted CO2 conversion into fuels and chemical products involves a range of technologies aimed at driving industrial decarbonization methods. In this work, we report on the development of a series of multifunctional metal-organic frameworks (MOFs) based on nitro- or amino-functionalized UiO-66(M) (M: Zr or Zr/Ti) supported RuOx NPs as photocatalysts, having different energy band level diagrams, for CO2 hydrogenation under simulated concentrated sunlight irradiation. RuOx(1 wt %; 2.2 ± 0.9 nm)@UiO-66(Zr/Ti)-NO2 was found to be a reusable photocatalyst, to be selective for CO2 methanation (5.03 mmol g-1 after 22 h;, apparent quantum yield at 350, 400, and 600 nm of 1.67, 0.25, and 0.01%, respectively), and to show about 3-6 times activity compared with previous investigations. The photocatalysts were characterized by advanced spectroscopic techniques like femto- and nanosecond transient absorption, spin electron resonance, and photoluminescence spectroscopies together with (photo)electrochemical measurements. The photocatalytic CO2 methanation mechanism was assessed by operando FTIR spectroscopy. The results indicate that the most active photocatalyst operates under a dual photochemical and photothermal mechanism. This investigation shows the potential of multifunctional MOFs as photocatalysts for solar-driven CO2 recycling.

Dual-Track Multifunctional Bimetallic Metal-Organic Frameworks for Antibiotic Enrichment and Detection.

The improper use and overuse of antibiotics have led to significant burdens and detrimental effects on the environment, food supply, and human health. Herein, a magnetic solid-phase extraction program and an optical immunosensor based on bimetallic Ce/Zr-UiO 66 for the detection of antibiotics are developed. A magnetic Fe3O4@SiO2@Ce/Zr-UiO 66 metal-organic framework (MOF) is prepared to extract and enrich chloramphenicol from fish, wastewater, and urine samples, and a horseradish peroxidase (HRP)-Ce/Zr-UiO 66@bovine serum protein-chloramphenicol probe is used for the sensitive detection of chloramphenicol based on the dual-effect catalysis of Ce and HRP. In this manner, the application of Ce/Zr-UiO 66 in integrating sample pretreatment and antibiotic detection is systematically investigated and the associated mechanisms are explored. It is concluded that Ce/Zr-UiO 66 is a versatile dual-track material exhibiting high enrichment efficiency (6.37mg g-1) and high sensitivity (limit of detection of 51.3 pg mL-1) for chloramphenicol detection and serving as a multifunctional MOF for safeguarding public health and hygiene.