Mesoporous Framework Research Articles

Tea/Coffee Sustainable Nanoarchitectures Purify Wastewater.

Transforming spent coffee grounds and tea residues into valuable hierarchical porous materials presents a sustainable solution for environmental remediation due to the low cost, extensive availability, and versatile functionalized interface. Here, we systematically investigated tea polyphenol-mediated morphological transformation of spent coffee grounds to the synthesis of three-dimensional (3D) mesoporous metal-organic framework (MOF)-derived nanoarchitectured carbon composites. We adopted the sustainable cost-effective tea-coffee derivative to remove typical marine micropollutants, such as antibiotic wastewater, radioactive pollutants, and microplastics. This innovative adsorbent shows remarkable efficiency in antibiotic adsorption, achieving up to 99.62% removal of tetracycline (TC), with an impressive maximum adsorption capacity of 373.1 mg/g. It also demonstrates a remarkable ability to remove marine microplastics and radioactive pollutants with immediate nuclear threats and global sanitation and health crisis posed by Fukushima nuclear waste toward the world. The innovative strategy of treating waste with waste highlights economic potential in wastewater treatment.

Spatiotemporal Encapsulation of Tandem Enzymes in Hierarchical Metal-Organic Frameworks for Cofactor-Dependent Photoenzymatic CO2 Conversion.

The photo-enzyme coupling system (PECS) holds immense potential in "green" biomanufacturing, encompassing the realms of pharmaceuticals, fuels, and carbon sequestration. Nevertheless, the intricate nature of enzymes' structures significantly impedes the seamless integration of multiple enzymes in a precise, tandem fashion, with exact control over their distribution, posing a formidable challenge. Herein, it has devised a mesoporous csq-type metal organic framework (Zr-MOF) from meso-tetrakis-(4-((phenyl)ethynyl)benzoate)porphyrin (Por-PTP) and Zr6(μ3-O)4(μ3-OH)4(OH)4(H2O)4) nodes (Zr6clusters), featuring intricate hierarchical hexagonal (5.8nm) and triangular (2.9nm) channels, enabling the simultaneous encapsulation of Formate dehydrogenase from Candida boidinii (CbFDH)and ferredoxin-NADP+ reductase (FNR) via a spatiotemporally controlled strategy for cofactor-dependent photoenzymatic carbon dioxide (CO2) conversion. Upon illumination, photoexcited electrons originating from the Zr-MOF frameworks migrate to the adjacent FNR for cofactor NADH regeneration, which is then harnessed by proximal CbFDH for CO2 fixation. Concurrently, the resulting holes are neutralized by AA for system recovery. The results demonstrated the confinement of tandem enzymes within MOF channels significantly enhanced the performance of multi-enzyme cascade pathways as well as augmenting the local NAD+/NADH, which leading to a further improvement in the efficiency of tandem biocatalytic formic acid generation (55mm) from CO2. Crucially, the photo-enzyme-coupled factories exhibited remarkable stability alongside exceptional recyclability, attributed to the preservation of MOF skeletons.

Fast Production of Covalent Organic Frameworks for Covalent Enzyme Immobilization with Boosted Enzymatic Catalysis by Solar‐Driven Photothermal Effect

AbstractDeveloping new enzyme‐immobilization systems to stabilize their dynamic structures and meanwhile enhance their catalytic activity is of great significance but very challenging. Herein, we design and fabricate a class of robust mesoporous covalent organic frameworks (COFs) via Michael addition‐elimination reaction. It is found that highly crystalline COFs can be produced in 10 min, which is attributed to the promoting effect of the intramolecular hydrogen bond activation. The COFs rich in hydroxyl groups can be facilely post‐modified by epibromohydrin to covalently immobilize enzymes with both high loading and activity. Furthermore, we create a solar‐driven photothermal‐promoted strategy by introducing photoactive azo groups to COF carriers, which can boost the enzyme catalytic performance (lipase) with much higher conversion of various racemic substrates and chiral resolution upon solar light irradiation. The heterogeneous biocatalysts also demonstrate exceptional reusability and stability. This work provides a green and energy‐efficient approach to facilitate the scale application of enzyme‐immobilized biocatalysts.

Fast Production of Covalent Organic Frameworks for Covalent Enzyme Immobilization with Boosted Enzymatic Catalysis by Solar-Driven Photothermal Effect.

Developing new enzyme-immobilization systems to stabilize their dynamic structures and meanwhile enhance their catalytic activity is of great significance but very challenging. Herein, we design and fabricate a class of robust mesoporous covalent organic frameworks (COFs) via Michael addition-elimination reaction. It is found that highly crystalline COFs can be produced in 10 min, which is attributed to the promoting effect of the intramolecular hydrogen bond activation. The COFs rich in hydroxyl groups can be facilely post-modified by epibromohydrin to covalently immobilize enzymes with both high loading and activity. Furthermore, we create a solar-driven photothermal-promoted strategy by introducing photoactive azo groups to COF carriers, which can boost the enzyme catalytic performance (lipase) with much higher conversion of various racemic substrates and chiral resolution upon solar light irradiation. The heterogeneous biocatalysts also demonstrate exceptional reusability and stability. This work provides a green and energy-efficient approach to facilitate the scale application of enzyme-immobilized biocatalysts.

Photoresponse enhanced CsPbBr3 quantum dots quantum-confined in mesoporous PCN-600 single crystal microwires

In this work, the CsPbBr3 quantum dots (QDs) are encapsulated into the mesoporous iron-based metal-organic framework (PCN-600) by using a two-step solvothermal method. The success formation of CsPbBr3@PCN-600 composite is confirmed via SEM, TEM, XRD, FTIR, EDS and other measurements. Besides, the characterization of fluorescence lifetime of CsPbBr3@PCN-600 composite reveals the presence of the electron transfer between PCN-600 and CsPbBr3 QDs. Especially, CsPbBr3@PCN-600 exhibits a prominent emission peak at 473 nm due to the quantum confinement effect, and the photoluminescence quantum yield of CsPbBr3 QDs protected by the mesoporous PCN-600 increases to 71% compared to 52% of the pristine CsPbBr3 QDs. Also, the protection of CsPbBr3 QDs by the PCN-600 channel enhances the luminescence stability, thermal stability and blue-light stability of CsPbBr3. In fact, under light illumination, the photogenerated carriers from the encapsulated CsPbBr3 QDs could be captured by catalytically active sites on the inner surface of the PCN-600 channel. This charge capture effect can increase the photocurrent and implies much effective separation of electron-hole pairs of the CsPbBr3@PCN-600 composite. These results make this composite a promising candidate for high-performance photoelectronic devices.

Unlocking of Hidden Mesopores for Enzyme Encapsulation by Dynamic Linkers in Stable Metal-Organic Frameworks.

Mesoporous metal-organic frameworks (MOFs) are promising supports for the immobilization of enzymes, yet their applications are often limited by small pore apertures that constrain the size of encapsulated enzymes to below 5 nm. In this study, we introduced labile linkers (4,4',4''-(2,4,6-boroxintriyl)-tribenzoate, TBTB) with dynamic boroxine bonds into mesoporous PCN-333, resulting in PCN-333-TBTB with enhanced enzyme loading and protection capabilities. The selective breaking of B-O bonds creates defects in PCN-333, which effectively expands both window and cavity sizes, thereby unlocking hidden mesopores for enzyme encapsulation. Consequently, this strategy not only increases the adsorption kinetics of small enzymes (<5 nm) such as cytochrome c (Cyt C) and horseradish peroxidase (HRP), but also enables the immobilization of various large-sized enzymes (>5 nm), such as glycoenzymes. The glycoenzymes@PCN-333-TBTB platform was successfully applied to synthesize thirteen complex oligosaccharides and polysaccharides, demonstrating high activity and enhanced enzyme stability. The dynamic linker-mediated enzyme encapsulation strategy enables the immobilization of enzymes exceeding the inherent pore size of MOFs, thus broadening the scope of enzymatic catalytic reactions achievable with MOF materials.

A review on progress and prospects of diatomaceous earth as a bio-template material for electrochemical energy storage: synthesis, characterization, and applications

AbstractThis comprehensive review explores the remarkable progress and prospects of diatomaceous earth (DE) as a bio-template material for synthesizing electrode materials tailored explicitly for supercapacitor and battery applications. The unique structures within DE, including its mesoporous nature and high surface area, have positioned it as a pivotal material in energy storage. The mesoporous framework of DE, often defined by pores with diameters between 2 and 50 nm, provides a substantial surface area, a fundamental element for charge storage, and transfer in electrochemical energy conversion and storage. Its bio-templating capabilities have ushered in the creation of highly efficient electrode materials. Moreover, the role of DE in enhancing ion accessibility has made it an excellent choice for high-power applications. As we gaze toward the future, the prospects of DE as a bio-template material for supercapacitor and battery electrode material appear exceptionally promising. Customized material synthesis, scalability challenges, multidisciplinary collaborations, and sustainable initiatives are emerging as key areas of interest. The natural abundance and eco-friendly attributes of DE align with the growing emphasis on sustainability in energy solutions, and its contribution to electrode material synthesis for supercapacitors and batteries presents an exciting avenue to evolve energy storage technologies. Its intricate structures and bio-templating capabilities offer a compelling path for advancing sustainable, high-performance energy storage solutions, marking a significant step toward a greener and more efficient future. Graphical Abstract

Ultrasound-assisted rapid growth of chemically bonded bifunctional mesoporous covalent organic framework submicrospheres on a nickel-chromium alloy support for efficient solid-phase microextraction of bisphenols from water and milk samples

A layer-by-layer chemical bonding strategy was developed for fast in situ growth of bifunctional mesoporous covalent organic framework submicrospheres (COF SMSs) on the nickel-chromium alloy (Ni-Cr) fiber substrate via the ultrasound-assisted Schiff-base reaction for the first time. COF SMSs showed well-defined morphology, extraordinary high surface area (1211 m2·g−1) and narrow mesopore (2.50 nm) as well as excellent stability. Furthermore, the resulting Ni-Cr fiber presented outstanding adsorption capability and improved selectivity for bisphenols (BPs). Consequently, an attractive SPME-HPLC-UV approach with the Ni-Cr@Ni-Cr LDHs NSs@COF SMSs fiber was proposed for rapid preconcentration and sensitive determination of BPs. By optimizing adsorption parameters, the SPME-HPLC-UV method presented good linearity for five BPs in the ranges of 0.02–200 ng·mL−1 with coefficients of determination (R2) higher than 0.999. Limits of detection and limits of quantitation were obtained from 0.003 ng·mL−1 to 0.006 ng·mL−1 and from 0.010 to 0.019 ng·mL−1, respectively. Moreover, the intra-day and inter-day precision expressed as relative standard deviations (RSDs) was 1.57–3.52 % and 2.65–4.38 % for the proposed method with a single fiber, respectively. RSDs of the proposed method with different duplicate fibers were 3.25–6.72 %. The proposed SPME-HPLC-UV method was available for efficient preconcentration and sensitive detection of five BPs from real water and milk samples. The relative recoveries at three spiking levels of BPs were achieved in the range of 80.00–118.8 % with RSDs below 7.81 %. In addition, the prepared fiber still exhibited satisfactory adsorption performance after 120 adsorption-desorption cycles.

Stability Assessment in Aqueous and Organic Solvents of Metal-Organic Framework PCN 333 Nanoparticles through a Combination of Physicochemical Characterization and Computational Simulations.

Mesoporous metal-organic frameworks (MOFs) have been recognized as powerful platforms for drug delivery, especially for biomolecules. Unfortunately, the application of MOFs is restricted due to their relatively poor stability in aqueous media, which is crucial for drug delivery applications. An exception is the porous coordination network (PCN)-series (e.g., PCN-333 and PCN-332), a series of MOFs with outstanding stability in aqueous media at the pH range from 3 to 9. In this study, we fabricate PCN-333 nanoparticles (nPCN) and investigate their stability in different solvents, including water, ethanol, and methanol. Surprisingly, the experimental characterizations in terms of X-ray diffraction, Brunauer-Emmett-Teller (BET), and scanning electron microscopy demonstrated that nPCN is not as stable in water as previously reported. Specifically, the crystalline structure of nPCN lost its typical octahedral shape and even decomposed into an irregular amorphous form when exposed to water for only 2 h, but not when ethanol and methanol were used. Meanwhile, the porosity of nPCN substantially diminished while being exposed to water, as demonstrated by the BET measurement. With the assistance of computational simulations, the mechanism behind the collapse of PCN-333 is illuminated. By molecular dynamics simulation and umbrella sampling, we elucidate that the degradation of PCN-333 occurs by hydrolysis, wherein polar solvent molecules initiate the attack and subsequent breakage of the metal-ligand reversible coordination bonds.

Enantiospecific profiling of D-amino acid for gastric cancer diagnosis by using a biocatalytic MHOF nanoreactor

The dynamic variation of D-amino acids (D-AAs) in human saliva has great potential as the indicator for individual physiological states and disease progression; however, enantiospecific profiling of D-AAs is a great challenge. In this work, a nanoreactor based on mesoporous hydrogen-bonded organic framework (MHOF) has been fabricated for the enantiospecific profiling of D-AAs. The nanoreactor is prepared by using MHOFs as the scaffold to organize the biocatalytic cascade of D-AA oxidase (DAAO) and horseradish peroxidase (HRP). In the meanwhile, the large, stable, and robust transport channels of MHOFs allow the unimpeded transport of the involved biocatalytic substrates. Once D-AA substrates efficiently transport into MHOFs, the chromogenic reactions of 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2 can be activated. So, using this MHOF nanoreactor, enantiospecific and visual detection of D-AAs can be achieved. Moreover, the stable nanoreactor can be operated in complex solution and utilized for the profiling of D-AA levels in saliva samples collected from gastric cancer patients, suggesting that D-AAs may be a powerful fingerprint for the diagnosis of gastric cancer. Therefore, the fabricated MHOF-based nanoreactor may provide an emerging tool for the enantiospecific profiling of D-AAs and supports the D-AA fingerprint as the indicator of gastric cancer diagnosis.

Bifunctional mesoporous HMUiO-66-NH2 nanoparticles for bone remodeling and ROS scavenging in periodontitis therapy

Periodontal bone defects represent an irreversible consequence of periodontitis associated with reactive oxygen species (ROS). However, indiscriminate removal of ROS proves to be counterproductive for tissue repair and insufficient for addressing existing bone defects. In the treatment of periodontitis, it is crucial to rationally alleviate local ROS while simultaneously promoting bone regeneration. In this study, Zr-based large-pore hierarchical mesoporous metal-organic framework (MOF) nanoparticles (NPs) HMUiO-66-NH2 were successfully proposed as bifunctional nanomaterials for bone regeneration and ROS scavenging in periodontitis therapy. HMUiO-66-NH2 NPs demonstrated outstanding biocompatibility both in vitro and in vivo. Significantly, these NPs enhanced the osteogenic differentiation of bone mesenchymal stem cells (BMSCs) under normal and high ROS conditions, upregulating osteogenic gene expression and mitigating oxidative stress. Furthermore, in vivo imaging revealed a gradual degradation of HMUiO-66-NH2 NPs in periodontal tissues. Local injection of HMUiO-66-NH2 effectively reduced bone defects and ROS levels in periodontitis-induced C57BL/6 mice. RNA sequencing highlighted that differentially expressed genes (DEGs) are predominantly involved in bone tissue development, with notable upregulation in Wnt and TGF-β signaling pathways. In conclusion, HMUiO-66-NH2 exhibits dual functionality in alleviating oxidative stress and promoting bone repair, positioning it as an effective strategy against bone resorption in oxidative stress-related periodontitis.

Bifunctionally Electrocatalytic Bromine Redox Reaction by Single-Atom Catalysts for High-Performance Zinc Batteries.

Aqueous zinc-bromine (Zn||Br2) batteries are regarded as one of the most promising energy storage devices due to their high safety, theoretical energy density, and low cost. However, the sluggish bromine redox kinetics and the formation of a soluble tribromide (Br3 -) hinder their practical applications. Here, it is proposed dispersed single iron atom coordinated with nitrogen atoms (FeN5) in a mesoporous carbon framework (FeSAC-CMK) as a conductive catalytic bromine host, which possesses porous structure and electrocatalytic functionality of FeN5 species for enhanced confinement and electrocatalytic effect. The active FeN5 species can fix the bromine (Br0) species to suppress the formation of Br3 - effectively and bifunctionally catalyze the bromide (Br-)/Br° conversion. These free up 1/3 Br- locked by Br3 - complexing agent for enhanced bromine utilization efficiency and conversion reversibility. Accordingly, the Zn||Br2 battery with FeSAC-CMK delivers an impressive specific capacity of 344 mAh g-1 at 0.2 A g-1 and superior rate capability with 164 mAh g-1 achieved even at 20 A g-1, much higher than that of inactive CMK (262 mAh g-1 at 0.2 A g-1; 6 mAh g-1 at only 8 A g-1). Furthermore, the battery demonstrates excellent cycling performance of 88% capacity retention after 2000 cycles.

Immobilization of laccase on mesoporous metal organic frameworks for efficient cross-coupling of ethyl ferulate.

Laccases act as green catalysts for oxidative cross-coupling of phenolic antioxidnt compounds, but low stability and non-recyclability limit its application. To address that, metal-organic frameworks Cu-BTC and Cr-MOF were synthesized as supports to immobilize the efficient laccase from Cerrena sp. HYB07. The Brunauer-Emmett-Teller surface area of Cu-BTC and Cr-MOF were 1213.2 and 907.1m2/g, respectively. The two carriers respectively presented pore diameters of 1.2-10nm and 1.4-12nm as octahedron, indicating nano-scale mesoporosity. These Cu-BTC and Cr-MOF carriers could adsorb laccase with enzyme loading of 1933.2 and 1564.4U/g carrier, respectively. The stability and organic solvent tolerance of Cu-BTC-laccase and Cr-MOF-laccase were both obviously improved compared to free laccase. Thermal inactivation kinetics showed that both the two immobilized laccases displayed lower thermal inactivation rate constants. Importantly, the Cu-BTC-laccase and Cr-MOF-laccase both showed much higher activity for cross-coupling of ethyl ferulate than free laccase, which had 2.5-fold higher cross-coupling efficiency than that by free laccase. The ethyl ferulate coupling product was also analyzed by mass spectroscopy and the synthesis pathway of ethyl ferulate dimer was proposed. The cross coupling of ethyl ferulate required the formation of radical intermediates of ethyl ferulate generated by laccase mediated oxidation. This work paved the way for MOFs immobilized laccase for cross coupling of antioxidant phenols.

Y and ZSM-5 Hierarchical Zeolites Prepared Using a Surfactant-Mediated Strategy: Effect of the Treatment Conditions.

Diffusional limitations associated with zeolite microporous systems can be overcome by developing hierarchical zeolites, i.e., materials with a micro- and mesoporous framework. In this work, Y and ZSM-5 zeolites were modified using a surfactant-mediated hydrothermal alkaline method, with NaOH and cetyltrimethylammonium bromide (CTAB). For Y zeolite, after a mild acidic pretreatment, the effect of the NaOH+CTAB treatment time was investigated. For ZSM-5 zeolite, different concentrations of the base and acid solutions were tested in the two-step pretreatment preceding the hydrothermal treatment. The properties of the materials were studied with different physical-chemical techniques. Hierarchical Y zeolites were characterized by 3.3-5 nm pores formed during the alkaline treatment through the structure reconstruction around the surfactant aggregates. The effectiveness of the NaOH+CTAB treatment was highly dependent on the duration. For intermediate treatment times (6-12 h), both smaller and larger mesopores were also obtained. Hierarchical ZSM-5 zeolites showed a disordered mesoporosity, mainly resulting from the pretreatment rather than from the subsequent hydrothermal treatment. High mesoporosity was obtained when the concentration of the pretreating base solution was sufficiently high and that of the acid one was not excessive. Hierarchical materials can be obtained for both zeolite structures, but the pretreatment and treatment conditions must be tailored to the starting zeolite and the desired type of mesoporosity.

One-Dimensional Single-Crystal Mesoporous TiO2 Supported CuW6O24 Clusters as Photocatalytic Cascade Nanoreactor for Boosting Reduction of CO2 to CH4.

Constructing nanoreactors with multiple active sites in well-defined crystalline mesoporous frameworks is an effective strategy for tailoring photocatalysts to address the challenging of CO2 reduction. Herein, one-dimensional (1-D) mesoporous single-crystal TiO2 nanorod (MS-TiO2-NRs, ≈110nm in length, high surface area of 117 m2 g-1, and uniform mesopores of ≈7.0nm) based nanoreactors are prepared via a droplet interface directed-assembly strategy under mild condition. By regulating the interfacial energy, the 1-D mesoporous single-crystal TiO2 can be further tuned to polycrystalline fan- and flower-like morphologies with different oxygen vacancies (Ov). The integration of single-crystal nature and mesopores with exposed oxygen vacancies make the rod-like TiO2 nanoreactors exhibit a high-photocatalytic CO2 reduction selectivity to CO (95.1%). Furthermore, photocatalytic cascade nanoreactors by in situ incorporation of CuW6O24 (W-Cu) clusters onto MS-TiO2-NRs via Ov are designed and synthesized, which improved the CO2 adsorption capacity and achieved two-step CO2-CO-CH4 photoreduction. The second step CO-to-CH4 reaction induced by W-Cu sites ensures a high generation rate of CH4 (420.4µmol g-1 h-1), along with an enhanced CH4 selectivity (≈94.3% electron selectivity). This research provides a platform for the design of mesoporous single-crystal materials, which potentially extends to a range of functional ceramics and semiconductors for various applications.

Spatially Separated Cu/Ru on Ordered Mesoporous Carbon for Superior Ammonia Electrosynthesis from Nitrate over a Wide Potential Window.

Nitrate (NO3-) in wastewater poses a serious threat to human health and the ecological environment. The electrocatalytic NO3- reduction to ammonia (NH3) reaction (NO3-RR) emerges as a promising carbon-free energy route for enabling NO3- removal and sustainable NH3 synthesis. However, it remains a challenge to achieve high Faraday efficiencies at a wide potential window due to the complex multiple-electron reduction process. Herein, spatially separated dual-metal tandem electrocatalysts made of a nitrogen-doped ordered mesoporous carbon support with ultrasmall and high-content Cu nanoparticles encapsulated inside and large and low-content Ru nanoparticles dispersed on the external surface (denoted as Ru/Cu@NOMC) are designed. In electrocatalytic NO3-RR, the Cu sites can quickly convert NO3- to adsorbed NO2- (*NO2-), while the Ru sites can efficiently produce active hydrogen (*H) to enhance the kinetics of converting *NO2- to NH3 on the Cu sites. Due to the synergistic effect between the Cu and Ru sites, Ru/Cu@NOMC exhibits a maximum NH3 Faradaic efficiency (FENH3) of approximately 100% at -0.1 V vs reversible hydrogen electrode (RHE) and a high NH3 yield rate of 1267 mmol gcat-1 h-1 at -0.5 V vs RHE. Finite element method (FEM) simulation and electrochemical in situ Raman spectroscopy revealed that the mesoporous framework can enhance the intermediate concentration due to the in situ confinement effect. Thanks to the Cu-Ru synergistic effect and the mesopore confinement effect, a wide potential window of approximately 500 mV for FENH3 over 90% and a superior stability for NH3 production over 156 h can be achieved on the Ru/Cu@NOMC catalyst.

Synthesis of Jasminaldehyde (α-pentylcinnamaldehyde) using Cs-AlMCM-41 Nanoparticle as Heterogeneous Solid Base Catalyst

In this study, the ultra-small mesoporous Cs-AlMCM-41 nanoparticle materials were obtained with high specific BET surface areas in the range of 426 m2g-1 with 1.97 nm pore size. The pore volume was found to be 0.86 cm3. The material possesses a basic site due to caesium ions (Cs+) counterbalancing the negative rise by Al in the mesoporous framework. The basicity of the sample was found to be 115.48 mol g-1. The basicity was proven via the condensation reaction of heptanal and benzaldehyde using microwave irradiation with a microwave power of 800 W. The sample (Cs-MCM-41) gave a higher conversion of heptanal (73.8%) with (70.1%) selectivity to jasminaldehyde. The CsMCM-41 can be a promising base catalyst in aldol condensation reaction for the synthesis of jasminaldehyde under autogenous pressure. Hence, the solid catalyst is easily recycled up to five (5) times with minimal loss of activity due to washing.

Single-Atom Au-Functionalized Mesoporous SnO2 Nanospheres for Ultrasensitive Detection of Listeria monocytogenes Biomarker at Low Temperatures.

Semiconductor metal oxide gas sensors have been proven to be capable of detecting Listeria monocytogenes, one kind of foodborne bacteria, through monitoring the characteristic gaseous metabolic product 3-hydroxy-2-butanone. However, the detection still faces challenges because the sensors need to work at high temperatures and output limited gas sensing performance. The present study focuses on the design of single-atom Au-functionalized mesoporous SnO2 nanospheres for the sensitive detection of ppb-level 3-hydroxy-2-butanone at low temperatures (50 °C). The fabricated sensors exhibit high sensitivity (291.5 ppm-1), excellent selectivity, short response time (10 s), and ultralow detection limit (10 ppb). The gas sensors exhibit exceptional efficacy in distinguishing L. monocytogenes from other bacterial strains (e.g., Escherichia coli). Additionally, wireless detection of 3-hydroxy-2-butanone vapor is successfully achieved through microelectromechanical systems sensors, enabling real-time monitoring of the biomarker 3-hydroxy-2-butanone. The superior sensing performance is ascribed to the mesoporous framework with accessible active Au-O-Sn sites in the uniform sensing layer consisting of single-atom Au-modified mesoporous SnO2 nanospheres, and such a feature facilitates the gas diffusion, adsorption, and catalytic conversion of 3-hydroxy-2-butanone molecules in the sensing layer, resulting in excellent sensing signal output at relatively low temperature that is favorable for developing low-energy-consumption gas sensors.

Design of Three-Dimensional Mesoporous Adamantane-Based Covalent Organic Framework with Exceptionally High Surface Areas.

The development of three-dimensional (3D) covalent organic frameworks (COFs) with large pores and high specific surface areas is of critical for practical applications. However, it remains a tremendous challenge to reconcile the contradiction between high porosity and high specific surface areas, and increasing the length of building blocks leads to structural interpenetration in 3D COFs. Here, we report the preparation of mesoporous three-dimensional COF by a new steric hindrance engineering method. By incorporating adamantane into the monomers instead of carbon centers, we successfully achieve 2-fold interpenetrated diamondoid-structured 3D COFs, featuring permanent mesopores (up to 33 Å), exceptionally high surface areas (>3400 m2 g-1), and low crystal densities (0.123 g cm-3). These properties far surpass those of most conventional 3D COFs with similar topologies. This work not only aims to construct 3D COFs with low interpenetration but also to establish a foundation for the systematic design and structural control of 3D COFs.

Structural Diversity Enables Dramatic Changes in Photocatalytic Efficiency of Porphyrinosilica Particles in Chem-Bio Binary Applications

Because of their potential applications in catalysis, separation, and gas storage, porous materials such as metal–organic frameworks (MOFs), porous coordination polymers (PCPs), porous organic polymers (POPs), and polymers with intrinsic microporosity (PIMs) have received much attention. Various building blocks have been introduced with various functional groups. Among the various organic building blocks, porphyrin has become one of the most important building blocks for the construction of such materials witnessed by a wide range of molecular architectures using porphyrin derivatives with various applications. In addition, they are often used to modify the surface of porous silica materials such as SBA-15, MCM-41 and MCM-48, because these porous silica materials exhibit narrow pore size distributions, high thermal stability and easy accessibility.In this presentation, a series of highly ordered mesoporous porphyrinosilicas akin to MCM-41 will be discussed, as novel recyclable heterogeneous photocatalysts, demonstrating their efficacy in the selective oxidation. Porphyrins are recognized as efficient photocatalysts for oxidation reactions, attributed to their capacity to generate reactive oxygen species (ROS). Integrating them into a mesoporous silica framework can mitigate self-degradation, thereby yielding an efficient catalytic system with an extended operational lifetime.