This research explores the influence of crystallinity on gas chromatographic(GC) separation using covalent organic frameworks(COFs) as stationary phases.Three COF materials(CTF-DCBs) with varying crystallinity were sy...This research explores the influence of crystallinity on gas chromatographic(GC) separation using covalent organic frameworks(COFs) as stationary phases.Three COF materials(CTF-DCBs) with varying crystallinity were synthesized and characterized.CTF-DCB-1,with superior crystallinity,demonstrated highselectivity GC separation of benzene isomers as well as styrene/phenylacetylene mixtures,while CTFDCB-2 and CTF-DCB-3 exhibited lower crystallinity and worse separation performance.Thermodynamic and kinetic tests showed that CTF-DCB-1 had the worst thermodynamic adsorption but low diffusion mass transfer resistance,which resulted in the best separation.Therefore,optimizing the crystallinity of COFs is necessary for balancing the kinetic diffusion and thermodynamic interactions towards the analytes,achieving high-performance GC stationary phases.展开更多
For chromatographic separation,the reasonable modulation of stationary phases is the key factor to achieve high separation performance.We proposed that developing MOF stationary phases through precisely modulating the...For chromatographic separation,the reasonable modulation of stationary phases is the key factor to achieve high separation performance.We proposed that developing MOF stationary phases through precisely modulating the thermodynamic interactions between MOFs and analytes is conducive to improving the separation resolution.MIL-125,MIL-125-NH_(2),MIL-143-BTB,and MIL-143-TATB were developed as stationary phases with the careful modulation of organic ligands.MIL-125-NH_(2)and MIL-143-TATB coated columns exhibited much better separation performance than their counterparts,MIL-125 and MIL-143-BTB,respectively.The investigation of the separation mechanism indicated that thermodynamic interaction,rather than kinetic diffusion,was responsible for the separation improvement.MIL-125-NH_(2)and MIL-143-TATB provided stronger and distinguishable interactions with targets than corresponding MIL-125 and MIL-143-BTB,respectively,resulting in enhanced separation performance.This work demonstrates a guide to improving the separation performance of MOF stationary phases by increasing the thermodynamic interactions between MOFs and analytes.展开更多
Cu-based metal-organic frameworks(MOFs)are widely employed in CO_(2)reduction reactions(CO_(2)RR).Mostly,the in-situ reconstructed derivatives such as Cu or Cu oxides during CO_(2)RR are regarded as the catalytic acti...Cu-based metal-organic frameworks(MOFs)are widely employed in CO_(2)reduction reactions(CO_(2)RR).Mostly,the in-situ reconstructed derivatives such as Cu or Cu oxides during CO_(2)RR are regarded as the catalytic active center for the formation of catalytic products.However,in many cases,the pristine MOFs still exist during the catalytic process,the key role of these pristine MOFs is often ignored in revealing the catalytic mechanism.Here,we designed two Cu(imidazole)with different coordination environments,namely CuN_(2)and Cu_(2)N_(4)for CO_(2)RR.The structures of the two MOFs were still remained after the catalytic reaction.We discovered that the pristine MOFs served as activation catalysts for converting CO_(2)into CO.Sequentially,the Cu-based derivatives,in the two cases,Cu(111)converted the CO into C_(2+)products.The CuN_(2)with more exposed Cu-N centers showed a higher FE_(CO)and a higher final FEC_(2+)than Cu_(2)N_(4).This auto-tandem catalytic mechanism was supported by electrocatalytic performance,TPD-CO,HRTEM,SAED,XPS,in-situ XANES and XES and DFT computation.The auto-tandem catalytic mechanism provides a new route to design Cu-based MOF electrocatalysts for high product selectivity in CO_(2)RR.展开更多
Enantiomer identification is of paramount industrial value and physiological significance.Construction of sensitive chiral sensors with high enantiomeric discrimination ability is highly desirable.In this work,a chira...Enantiomer identification is of paramount industrial value and physiological significance.Construction of sensitive chiral sensors with high enantiomeric discrimination ability is highly desirable.In this work,a chiral covalent organic framework/anodic aluminum oxide(c-COF/AAO)membrane was prepared for electrochemical enantioselective recognition and sensing.Benefiting from the remarkable asymmetry,the asprepared nanofluidic c-COF/AAO presents a distinct ion current rectification(ICR)characteristic,enabling sensitive bioanalysis.In addition,owing to the large surface area,high chemical stability and perfect ion selectivity of chiral COF,the prepared c-COF/AAO membrane presents exceptionally selective mass transport and thereby enables excellent chiral discrimination for S-/R-Naproxen(S-/R-Npx)enantiomers.It is especially noteworthy that the detection limit is achieved as low as 3.88 pmol/L.These results raise the possibility for a facile,stable and low-cost method to carry out sensitive enantioselective recognition and detection.展开更多
Although molybdenum disulfide (MoS_(2))-based materials are generally known as active electrocatalysts for the hydrogen evolution reaction (HER), the inert performance for the oxygen evolution reaction (OER) seriously...Although molybdenum disulfide (MoS_(2))-based materials are generally known as active electrocatalysts for the hydrogen evolution reaction (HER), the inert performance for the oxygen evolution reaction (OER) seriously limits their wide applications in alkaline electrolyzers due to there exists too strong metal-sulfur (M−S) bond in MoS_(2). Herein, by means of surface reorganization engineering of bimetal Al, Co-doped MoS_(2) (devoted as AlCo_(3)-MoS_(2)) through in situ substituting partial oxidation, we successfully significantly activate the OER activity of MoS_(2), which affords a considerably low overpotential of 323 mV at −30 mA cm^(−2), far lower than those of MoS_(2), Al-MoS_(2) and Co-MoS_(2) catalysts. Essentially, the AlCo_(3)-MoS_(2) substrate produces lots of M−O (M=Al, Co and Mo) species with oxygen vacancies, which trigger the surface self-reconstruction of pre-catalysts and simultaneously boost the electrocatalytic OER activity. Moreover, benefiting from the moderate M−O species formed on the surface, the redistribution of surface electron states is induced, thus optimizing the adsorption of OH* and OOH* intermediates on metal oxyhydroxides and awakening the OER activity of MoS_(2).展开更多
The saccharification of cellulosic biomass to produce biofuels and chemicals is one of the most promising industries for gree n-power production and sustainable development.Cellulase is the core component in the sacch...The saccharification of cellulosic biomass to produce biofuels and chemicals is one of the most promising industries for gree n-power production and sustainable development.Cellulase is the core component in the saccharification process.Simple and efficient assay method to determine cellulase activity in saccharification is thus highly required.In this work,a boronate-affinity surface based renewable and ultrasensitive electrochemical sensor for cellulase activity determination has been fabricated.Through bo ronate-sugar interaction,celluloses are attached to the electrode surface,forming the cellulose na nonetwork at the sensing interface.Cellulase degradation can lead to the variation of electrochemical impedance.Thus,electrochemical impedance signal can reflect the cellulase activity.Importantly,via fully utilizing the boronate-affinity chemistry that enables reversible fabrication of cellulose nanonetwork,a renewable sensing surface has been firstly constructed for cellulase activity assay.Thanks to interfacial diffusion process of electrochemical sensor,the product inhibitory effect in the cellulase activity assays can be circumvented.The proposed electrochemical sensor is ultrasensitive for label-free cellulase activity detection with a very simple fabrication process,showing great potential for activity screen of new enzymes in saccharification conversion.展开更多
Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. The research field of solid-state nanopore starts from mimicking...Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. The research field of solid-state nanopore starts from mimicking the biological nanopore in living cells. Understanding the transport mechanism of biological nanopore in vivo is a big challenge because of the experimental difficulty, so it is essential to establish the basic research of artificial nanopores in vitro especially for the analysis of ions and small molecules. The performance of solid-state nanopores could be evaluated by monitoring currents when ions and molecules passed through. The comparison of the two types of nanopores based on current-derived information can reveal the principle of biological nanopores, while the solid-state nanopores are applied into practical bioanalysis. In this review, we focus on the researches of the solid-state nanopores in the fabrication process and in the analysis of ions and small molecules. Fabrication methods of nanopores,ion transport mechanism, small molecule analysis and theoretical studies are discussed in detail.展开更多
The searches for large-gap quantum spin Hall insulators are important for both practical and fundamental inter- ests. In this work, we present a theoretical observation of the two-dimensional fully fluorinated stanene...The searches for large-gap quantum spin Hall insulators are important for both practical and fundamental inter- ests. In this work, we present a theoretical observation of the two-dimensional fully fluorinated stanene （SnF） by means of density functional theory. Remarkably, a significant spin-orbit coupling is observed for the SnF monolayer in the valence band at the F point, with a considerable indirect band gap of 278 meV. The direct gap of the SnF monolayer is at the F point, which is slightly larger by as much as 381 meV. In addition, the elastic modulus of the SnF monolayer is about 20J/m^2, which is comparable with the in-plane stiffness of black phos- phorus monolayer along the x-direction （~28.94 J/m^2）. Finally, the optical properties of stanene, SnF monolayer and stanene/SnF bilayer are calculated, in which the stanene/SnF bilayer is supposed to be an attractive sunlight absorber.展开更多
To identify the aggregates causing the alkali-silica reaction, and the reactivity of rocks in different parts of China, the mineral and texture characteristics of some typical coarse ag gregates and the alkali reactiv...To identify the aggregates causing the alkali-silica reaction, and the reactivity of rocks in different parts of China, the mineral and texture characteristics of some typical coarse ag gregates and the alkali reactivity of these aggregates were systematically investigated. On one hand, petrographic examination of aggregates, combined with X-ray diffraction analysis, chemical analysis, scanning electron microscopy, was conducted for analyzing their mineralogy and texture. It was found that not only mineral characteristics, but also their interior structure would affect their potential alkali-silica reactivity. Furthermore, the alkali-silica reactivity of aggregates is due to their mineral compositions, such as containing different alkali-reactive minerals, while, different stuctures of those aggregates with similar minerals affect their reactivity to some extent. There are some amount of micro-aperture and cracks across the quartz in the aggregate, which may become the natural accesses for Na^＋, K^＋, and OH^- ions to intrude in the mortar or concrete during the process of alkali-silica reaction. Alkali-silica reactivity of the aggregates was detected by the accelerated mortar bars test. It was revealed that all the aggregates tested were alkali-silica reactive and the results were also in accordance with their mineral and structure analysis.展开更多
A general,facile and eco-friendly iron catalysis enables oxidation of unstrained tertiary aromatic alcohols to ketones through C-C bond cleavage even with H_(2)O_(2) as the oxidant.Notably,this transformation can tole...A general,facile and eco-friendly iron catalysis enables oxidation of unstrained tertiary aromatic alcohols to ketones through C-C bond cleavage even with H_(2)O_(2) as the oxidant.Notably,this transformation can tolerate oxidation-labile functional groups.The robustness of this method is further demonstrated on the late-stage oxidation of complex bioactive molecules.展开更多
Designing new two-dimensional （2D） semiconductors with novel topological characters is highly desirable for further material innovation. We propose a theoretical design of a stable 2D inorganic material, namely, bor...Designing new two-dimensional （2D） semiconductors with novel topological characters is highly desirable for further material innovation. We propose a theoretical design of a stable 2D inorganic material, namely, borane, which is jointly stabilized by traditional B B localized and unique B-H-B delocalized chemical bonds. In borane, the bonding natures along different directions are distinguishing, which lead to huge differences in mechanical strengths of 142.73 and 97.47N/m for a and b directions, respectively. In a unit cell, each hydrogen atom binds to two boron atoms forming a three-center-two-electron （3c-2e） bridge bond B H B. This can be considered as an extension of diborane molecules from OD to 2D. The collaboration of localized and delocalized chemical bonds endows borane with high structural stability, as indicated by its favorable cohesive energy, high mechanical strength, absence of imaginary modes in the phonon spectrum, and moderate melting point. Remarkably, borane has a fascinating electronic property featured with a Dirae-like ring in the electronic band structure. The unique bonding nature and electronic property in borane would attract intensive interests in both theory and experiment.展开更多
Titania microspheres were synthesized using hydrothermal methods to exploit a new liquid chromatography stationary phase. The prepared titania microspheres were approximately 7 μm in diameter, and the particle size d...Titania microspheres were synthesized using hydrothermal methods to exploit a new liquid chromatography stationary phase. The prepared titania microspheres were approximately 7 μm in diameter, and the particle size distribution was relatively narrow and uniform. Furthermore, the average specific surface area was 276.0 m2·g·1, the average pore volume was approximately 0.25 mL·g·1, and the pore diameter was approximately 35.9 nm for sintering titania microspheres. These parameters indicate that the titania microspheres prepared for this study have excellent surface properties for chromatography. Additionally, columns filled with the titania microspheres were able to separate basic compounds, including benzene, nitrobenzene and o-nitroanisole. It could be proposed that the titania microspheres prepared for this study would be a promising stationary phase for liquid chromatography.展开更多
Practical,undirected and selective catalytic functionalization of unactivated arenes remains a challenging problem in organic synthesis.We herein report a bioinspired L-cystine-derived ligand BCPOM/Fe-enabled innate C...Practical,undirected and selective catalytic functionalization of unactivated arenes remains a challenging problem in organic synthesis.We herein report a bioinspired L-cystine-derived ligand BCPOM/Fe-enabled innate C-H difluoromethylation of unactivated arenes as limiting reagents with stable and inexpensive BrCF_(2)CO_(2)Et as the difluoromethylation source in high efficiency.Notably,this method uses environmentally benign H_(2)O_(2) as the sole oxidant,and enables late-stage functionalization and exceptionally functional-group tolerance,even including oxidation-labile aldehyde,phenolic hydroxy,primary amine,and boronic acid groups,which is difficult to access by current means.展开更多
Mass transport processes across multiple length scales underpin a wide range of natural phenomena and technological applications.Among them,the chimney effect,widely observed at the macroscopic scale,refers to the con...Mass transport processes across multiple length scales underpin a wide range of natural phenomena and technological applications.Among them,the chimney effect,widely observed at the macroscopic scale,refers to the convective flow induced by density differences within a hollow channel,where warm air rises and cooler air flows in to replace it,creating a natural pressure difference[1,2].This effect has been extensively harnessed in diverse applications,including solar chimney power plants,building ventilation systems,and photothermal evaporation platforms[3,4].展开更多
Niobium oxide(Nb_(2)O_(5))is a promising material in photocatalytic,solar cell,electronic like electron field emitters,and especially lithium-ion batteries(LIBs)because of its adjustable morphologies,controllable crys...Niobium oxide(Nb_(2)O_(5))is a promising material in photocatalytic,solar cell,electronic like electron field emitters,and especially lithium-ion batteries(LIBs)because of its adjustable morphologies,controllable crystal type,stable structure,and environmental friendliness.However,its low electrical conductivity lowers the rate performance and limits the practical applications in LIBs.Herein,we present a one-step solid-state synthesis of orthogonal Nb_(2)O_(5) nanocrystals/graphene composites(Nb_(2)O_(5)/G)as high-performance anode materials in LIBs.Benefiting from the nanoscale crystalline structure Nb_(2)O_(5) and highly-conductive graphene substrate,the as-prepared Nb_(2)O_(5)/G exhibits excellent electrochemical performances.Impressively,a reversible structural phase transition between orthogonal Nb_(2)O_(5) and tetragonal Li1-xNbO_(2)(0<x<1)was verified by ex-situ transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).After coupling with graphite cathode based on PF6-intercalation/deintercalation mechanisms,Nb_(2)O_(5)/G||graphite dual-ion batteries(DIBs)full cell delivers good electrochemical performance in terms of cyclic performance and rate capability.We believe this work can provide a clear route towards developing advanced transition metal oxide/graphene composite anode and a comprehension of its electrochemical reaction mechanism.展开更多
Analyzing single organelles within the intricate compartmentalizedsystems of eukaryotic cells poses significantchallenges in biomedical research. Presently,assessment of organelle functions frequently relies onthe dis...Analyzing single organelles within the intricate compartmentalizedsystems of eukaryotic cells poses significantchallenges in biomedical research. Presently,assessment of organelle functions frequently relies onthe disjointed application of multiple techniques, resultingin constraints on the promptness and precision ofdata acquisition. Herein, a dual-nanopore electrochemicalbiosensor has been designed in this work to housedetection channels directly in living cells for in situ andconcurrent acquisition of multiple key characteristicsof a single mitochondrion. In one channel, mitochondrialreactive oxygen species (ROS) and associated adenosinetriphosphate (ATP) production are electrochemicallymeasured with a redox activatable probe(Apt-MB), while the parallel channel facilitates the measurementof mitochondrial ΔΨm via proton responsiveness.Quantitative assessment of the relationshipbetween ROS and ΔΨm against ATP production hasbeen achieved, which allows in-depth analysis of mitochondrialfunctions. With this approach, the resultsclearly show evolutionary stages of the apoptosis pathway,and highlight that mitochondrial proton circuitdecoupling may serve as an earlier event preceding thewell-known ROS accumulation stage. Hence, this studyunderscores the considerable usage of this approachfor comprehensive analysis of single mitochondrialfunctionality, and may further inspire the developmentof micro/nanoscale tools for multiparameter, high-fidelity,single-organelle analysis directly within cells.展开更多
Overall seawater splitting driven by regenerable electricity is an ideal pathway formass production of green hydrogen.Nonetheless,its anodic oxygen evolution half-reaction(OER)confronts sluggish kinetics,competitive c...Overall seawater splitting driven by regenerable electricity is an ideal pathway formass production of green hydrogen.Nonetheless,its anodic oxygen evolution half-reaction(OER)confronts sluggish kinetics,competitive chlorine evolution,and chloride corrosion or poisoning problems,needing to develop high-efficient and robust electrocatalysts toward those challenges.Herein,novel defect-rich single-phase(NiCoMnCrFe)_(3)O_(4) high-entropy spinel oxide(HEO)is fabricated by low-temperature annealing of highentropy layered double hydroxide precursor.Due to the presence of abundant defects,unique“cocktail”effect,and efficient electronic structure regulation,such(NiCoMnCrFe)_(3)O_(4) can deliver 500 mA cm^(−2) current density at the overpotentials of 268/384 mV in alkaline freshwater/seawater,outperforming its counterparts,commercial IrO_(2),and most reported OER catalysts.Moreover,it manifests exceptional OER durability and anticorrosion capability.Theoretical calculations reveal that the eg occupancies of surface Mn atoms are closer to 1.0,which may be the activity origin of such HEO.Importantly,the constructed(NiCoMnCrFe)_(3)O_(4)||Pt/C electrolyzer only requires 1.57 V cell voltage for driving overall seawater splitting to reach 500 mA cm^(−2) current under real industrial conditions.This work may spur the development of advanced OER electrocatalysts by combining entropy and defect engineering and accelerate their applications in seawater splitting,metal–air batteries,or marine biomass electrocatalytic conversion fields.展开更多
Meniscus injuries present significant therapeutic challenges due to their limited self-healing capacity and the diverse biological and mechanical properties across the tissue.Conventional repair strategies do not repl...Meniscus injuries present significant therapeutic challenges due to their limited self-healing capacity and the diverse biological and mechanical properties across the tissue.Conventional repair strategies do not replicate the complex zonal characteristics within the meniscus,resulting in suboptimal outcomes.In this study,we introduce an innovative fetal/adult and stiffness-tunable meniscus decellularized extracellular matrix(DEM)-based hydrogel system designed for precision repair of heterogeneous,zonal-dependent meniscus injuries.By syn-thesizing fetal and adult DEM hydrogels,we identified distinct cellular responses,including that hydrogels with adult meniscus-derived DEM promote more fibrochondrogenic phenotypes.The incorporation of methacrylated hyaluronic acid(MeHA)further refined the mechanical properties and injectability of the DEM-based hydrogels.The combination of fetal and adult DEM with MeHA allowed for precise tuning of stiffness,influencing cell differentiation and closely mimicking native tissue environments.In vivo tests confirmed the biocompatibility of hydrogels and their integration with native meniscus tissues.Furthermore,advanced 3D bioprinting techniques enabled the fabrication of hybrid hydrogels with biomaterial and mechanical gradients,effectively emulating the zonal properties of meniscus tissue and enhancing cell integration.This study represents a significant advance in meniscus tissue engineering,providing a promising platform for customized regenerative therapies across a range of heterogeneous fibrous connective tissues.展开更多
This paper reports a simple method for immobilization of acetylcholinesterase(AChE)on one-dimensional(1D)gold(Au)nanoparticles for detection of organophosphorous(OP)insecticides.1D Au nanoparticles were prepared by el...This paper reports a simple method for immobilization of acetylcholinesterase(AChE)on one-dimensional(1D)gold(Au)nanoparticles for detection of organophosphorous(OP)insecticides.1D Au nanoparticles were prepared by electrodeposition in the pores of an alumina template which was subsequently removed by 2.0 M NaOH solution.They were characterized by XRD and FESEM.The immobilized AChE retained its biological activity and catalyzed the hydrolysis of acetylthiocholine to form thiocholine,which was subsequently oxidized to produce detectable signals.Based on the inhibition toward the enzymatic activity of AChE by OP insecticides,sensitive detection of methamidophos(an OP insecticide)was performed.Under optimal conditions,the sensors could be used for the determination of methamidophos ranging from 0.004 to 24μg/mL with the detection limit of 0.001μg/mL.The developed OP insecticide biosensors exhibited satisfactory stability and reproducibility.This work demonstrated that 1D Au nanoparticles could serve as an ideal carrier for immobilization of AChE to fabricate the corresponding biosensor.展开更多
基金supported by the National Natural Science Foundation of China (Nos.22174067,22204078,and 22374077)the Natural Science Foundation of Jiangsu Province of China (No.BK20220370)+3 种基金Jiangsu Provincial Department of Education (No.22KJB150009)State Key Laboratory of Analytical Chemistry for Life Science (No.SKLACLS2218)the Priority Academic Program Development of Jiangsu Higher Education Institutions,Jiangsu Association for Science and Technology (No.TJ-2023-076)Shanghai Synchrotron Radiation Facility Beamline BL17B1 (No.2021-NFPSPT-006657)。
文摘This research explores the influence of crystallinity on gas chromatographic(GC) separation using covalent organic frameworks(COFs) as stationary phases.Three COF materials(CTF-DCBs) with varying crystallinity were synthesized and characterized.CTF-DCB-1,with superior crystallinity,demonstrated highselectivity GC separation of benzene isomers as well as styrene/phenylacetylene mixtures,while CTFDCB-2 and CTF-DCB-3 exhibited lower crystallinity and worse separation performance.Thermodynamic and kinetic tests showed that CTF-DCB-1 had the worst thermodynamic adsorption but low diffusion mass transfer resistance,which resulted in the best separation.Therefore,optimizing the crystallinity of COFs is necessary for balancing the kinetic diffusion and thermodynamic interactions towards the analytes,achieving high-performance GC stationary phases.
基金supported by the National Natural Science Foundation of China(Nos.22174067,22204078,22374077,and 22474059)the Natural Science Foundation of Jiangsu Province of China(No.BK20220370)+2 种基金Jiangsu Provincial Department of Education(No.22KJB150009)Jiangsu Association for Science and Technology(No.TJ-2023-076)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘For chromatographic separation,the reasonable modulation of stationary phases is the key factor to achieve high separation performance.We proposed that developing MOF stationary phases through precisely modulating the thermodynamic interactions between MOFs and analytes is conducive to improving the separation resolution.MIL-125,MIL-125-NH_(2),MIL-143-BTB,and MIL-143-TATB were developed as stationary phases with the careful modulation of organic ligands.MIL-125-NH_(2)and MIL-143-TATB coated columns exhibited much better separation performance than their counterparts,MIL-125 and MIL-143-BTB,respectively.The investigation of the separation mechanism indicated that thermodynamic interaction,rather than kinetic diffusion,was responsible for the separation improvement.MIL-125-NH_(2)and MIL-143-TATB provided stronger and distinguishable interactions with targets than corresponding MIL-125 and MIL-143-BTB,respectively,resulting in enhanced separation performance.This work demonstrates a guide to improving the separation performance of MOF stationary phases by increasing the thermodynamic interactions between MOFs and analytes.
基金supported by the National Natural Science Foundation of China(Nos.22174067 and 22204078)the Natural Science Foundation of Jiangsu Province of China(No.BK20220370)+2 种基金Jiangsu Provincial Department of Education(No.22KJB150009)State Key Laboratory of Analytical Chemistry for Life Science(No.SKLACLS2218)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Cu-based metal-organic frameworks(MOFs)are widely employed in CO_(2)reduction reactions(CO_(2)RR).Mostly,the in-situ reconstructed derivatives such as Cu or Cu oxides during CO_(2)RR are regarded as the catalytic active center for the formation of catalytic products.However,in many cases,the pristine MOFs still exist during the catalytic process,the key role of these pristine MOFs is often ignored in revealing the catalytic mechanism.Here,we designed two Cu(imidazole)with different coordination environments,namely CuN_(2)and Cu_(2)N_(4)for CO_(2)RR.The structures of the two MOFs were still remained after the catalytic reaction.We discovered that the pristine MOFs served as activation catalysts for converting CO_(2)into CO.Sequentially,the Cu-based derivatives,in the two cases,Cu(111)converted the CO into C_(2+)products.The CuN_(2)with more exposed Cu-N centers showed a higher FE_(CO)and a higher final FEC_(2+)than Cu_(2)N_(4).This auto-tandem catalytic mechanism was supported by electrocatalytic performance,TPD-CO,HRTEM,SAED,XPS,in-situ XANES and XES and DFT computation.The auto-tandem catalytic mechanism provides a new route to design Cu-based MOF electrocatalysts for high product selectivity in CO_(2)RR.
基金supported by grants from the National Natural Science Foundation of China(Nos.22274076,22304084)the Primary Research&Development Plan of Jiangsu Province(No.BE2022793)+1 种基金the Natural Science Foundation of Jiangsu Province of China(No.BK20230377)Jiangsu Provincial Department of Education(No.211090B52303)。
文摘Enantiomer identification is of paramount industrial value and physiological significance.Construction of sensitive chiral sensors with high enantiomeric discrimination ability is highly desirable.In this work,a chiral covalent organic framework/anodic aluminum oxide(c-COF/AAO)membrane was prepared for electrochemical enantioselective recognition and sensing.Benefiting from the remarkable asymmetry,the asprepared nanofluidic c-COF/AAO presents a distinct ion current rectification(ICR)characteristic,enabling sensitive bioanalysis.In addition,owing to the large surface area,high chemical stability and perfect ion selectivity of chiral COF,the prepared c-COF/AAO membrane presents exceptionally selective mass transport and thereby enables excellent chiral discrimination for S-/R-Naproxen(S-/R-Npx)enantiomers.It is especially noteworthy that the detection limit is achieved as low as 3.88 pmol/L.These results raise the possibility for a facile,stable and low-cost method to carry out sensitive enantioselective recognition and detection.
基金This work was supported by the NSFC(21501096,22075223)Natural Science Foundation of Jiangsu(BK20150086,BK20201120)+1 种基金the Foundation of the Jiangsu Education Committee(15KJB150020)the Six Talent Peaks Project in Jiangsu Province(JY-087)and the Innovation Project of Jiangsu Province.
文摘Although molybdenum disulfide (MoS_(2))-based materials are generally known as active electrocatalysts for the hydrogen evolution reaction (HER), the inert performance for the oxygen evolution reaction (OER) seriously limits their wide applications in alkaline electrolyzers due to there exists too strong metal-sulfur (M−S) bond in MoS_(2). Herein, by means of surface reorganization engineering of bimetal Al, Co-doped MoS_(2) (devoted as AlCo_(3)-MoS_(2)) through in situ substituting partial oxidation, we successfully significantly activate the OER activity of MoS_(2), which affords a considerably low overpotential of 323 mV at −30 mA cm^(−2), far lower than those of MoS_(2), Al-MoS_(2) and Co-MoS_(2) catalysts. Essentially, the AlCo_(3)-MoS_(2) substrate produces lots of M−O (M=Al, Co and Mo) species with oxygen vacancies, which trigger the surface self-reconstruction of pre-catalysts and simultaneously boost the electrocatalytic OER activity. Moreover, benefiting from the moderate M−O species formed on the surface, the redistribution of surface electron states is induced, thus optimizing the adsorption of OH* and OOH* intermediates on metal oxyhydroxides and awakening the OER activity of MoS_(2).
基金supported by the National Natural Science Foundation of China (Nos.21625502,21705079,21671105 and 21974070)the Natural Science Foundation of Jiangsu Province (Nos.BK20192008 and BK20171033)the financial support from the PAPD。
文摘The saccharification of cellulosic biomass to produce biofuels and chemicals is one of the most promising industries for gree n-power production and sustainable development.Cellulase is the core component in the saccharification process.Simple and efficient assay method to determine cellulase activity in saccharification is thus highly required.In this work,a boronate-affinity surface based renewable and ultrasensitive electrochemical sensor for cellulase activity determination has been fabricated.Through bo ronate-sugar interaction,celluloses are attached to the electrode surface,forming the cellulose na nonetwork at the sensing interface.Cellulase degradation can lead to the variation of electrochemical impedance.Thus,electrochemical impedance signal can reflect the cellulase activity.Importantly,via fully utilizing the boronate-affinity chemistry that enables reversible fabrication of cellulose nanonetwork,a renewable sensing surface has been firstly constructed for cellulase activity assay.Thanks to interfacial diffusion process of electrochemical sensor,the product inhibitory effect in the cellulase activity assays can be circumvented.The proposed electrochemical sensor is ultrasensitive for label-free cellulase activity detection with a very simple fabrication process,showing great potential for activity screen of new enzymes in saccharification conversion.
基金financially supported by the National Natural Science Foundation of China (No. 21505076)the Young Elite Scholar Support (YESS) Program from China Association for Science and Technology (No. YESS20150009)+2 种基金the Program of Jiangsu Specially-Appointed Professor, the Natural Science Foundation of Jiangsu Province of China (No. BK20150967)the Innovation Team Program of Jiangsu Province of Chinathe Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. The research field of solid-state nanopore starts from mimicking the biological nanopore in living cells. Understanding the transport mechanism of biological nanopore in vivo is a big challenge because of the experimental difficulty, so it is essential to establish the basic research of artificial nanopores in vitro especially for the analysis of ions and small molecules. The performance of solid-state nanopores could be evaluated by monitoring currents when ions and molecules passed through. The comparison of the two types of nanopores based on current-derived information can reveal the principle of biological nanopores, while the solid-state nanopores are applied into practical bioanalysis. In this review, we focus on the researches of the solid-state nanopores in the fabrication process and in the analysis of ions and small molecules. Fabrication methods of nanopores,ion transport mechanism, small molecule analysis and theoretical studies are discussed in detail.
基金Supported by the Science Foundation of Nanjing University of Posts and Telecommunications under Grant No NY215064the China Postdoctoral Science Foundation under Grant No 2015M581824the Jiangsu Post-doctoral Foundation under Grant No1501070B
文摘The searches for large-gap quantum spin Hall insulators are important for both practical and fundamental inter- ests. In this work, we present a theoretical observation of the two-dimensional fully fluorinated stanene （SnF） by means of density functional theory. Remarkably, a significant spin-orbit coupling is observed for the SnF monolayer in the valence band at the F point, with a considerable indirect band gap of 278 meV. The direct gap of the SnF monolayer is at the F point, which is slightly larger by as much as 381 meV. In addition, the elastic modulus of the SnF monolayer is about 20J/m^2, which is comparable with the in-plane stiffness of black phos- phorus monolayer along the x-direction （~28.94 J/m^2）. Finally, the optical properties of stanene, SnF monolayer and stanene/SnF bilayer are calculated, in which the stanene/SnF bilayer is supposed to be an attractive sunlight absorber.
基金Funded by the State "Key Base Development Foudation" Project("973") of China(201CD610706)Natural Science Foundation of Jiangsu Province,China(2007191SB90098)+1 种基金Analysis and Testing Method Projext of Department of Natural Science Foundation of Jiangsu Provice, China (2006191TS90140)the Scientific Research Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China (2006191XLH0132)
文摘To identify the aggregates causing the alkali-silica reaction, and the reactivity of rocks in different parts of China, the mineral and texture characteristics of some typical coarse ag gregates and the alkali reactivity of these aggregates were systematically investigated. On one hand, petrographic examination of aggregates, combined with X-ray diffraction analysis, chemical analysis, scanning electron microscopy, was conducted for analyzing their mineralogy and texture. It was found that not only mineral characteristics, but also their interior structure would affect their potential alkali-silica reactivity. Furthermore, the alkali-silica reactivity of aggregates is due to their mineral compositions, such as containing different alkali-reactive minerals, while, different stuctures of those aggregates with similar minerals affect their reactivity to some extent. There are some amount of micro-aperture and cracks across the quartz in the aggregate, which may become the natural accesses for Na^＋, K^＋, and OH^- ions to intrude in the mortar or concrete during the process of alkali-silica reaction. Alkali-silica reactivity of the aggregates was detected by the accelerated mortar bars test. It was revealed that all the aggregates tested were alkali-silica reactive and the results were also in accordance with their mineral and structure analysis.
基金the Natural Science Foundation of China(No.21776139)the“Qing Lan Project”Young and Middle-aged Academic Leaders of Jiangsu Provincial Colleges and Universities,and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘A general,facile and eco-friendly iron catalysis enables oxidation of unstrained tertiary aromatic alcohols to ketones through C-C bond cleavage even with H_(2)O_(2) as the oxidant.Notably,this transformation can tolerate oxidation-labile functional groups.The robustness of this method is further demonstrated on the late-stage oxidation of complex bioactive molecules.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61605087 and 61704083the International Postdoctoral Exchange Fellowship Program between JUELICH and OCPC under Grant No 20161001+2 种基金the Natural Science Foundation of Jiangsu Province under Grant No BK20160881the Jiangsu Provincial Natural Science Research Project under Grant No16KJB140010the Science Foundation of Nanjing University of Posts and Telecommunications under Grant No NY215064
文摘Designing new two-dimensional （2D） semiconductors with novel topological characters is highly desirable for further material innovation. We propose a theoretical design of a stable 2D inorganic material, namely, borane, which is jointly stabilized by traditional B B localized and unique B-H-B delocalized chemical bonds. In borane, the bonding natures along different directions are distinguishing, which lead to huge differences in mechanical strengths of 142.73 and 97.47N/m for a and b directions, respectively. In a unit cell, each hydrogen atom binds to two boron atoms forming a three-center-two-electron （3c-2e） bridge bond B H B. This can be considered as an extension of diborane molecules from OD to 2D. The collaboration of localized and delocalized chemical bonds endows borane with high structural stability, as indicated by its favorable cohesive energy, high mechanical strength, absence of imaginary modes in the phonon spectrum, and moderate melting point. Remarkably, borane has a fascinating electronic property featured with a Dirae-like ring in the electronic band structure. The unique bonding nature and electronic property in borane would attract intensive interests in both theory and experiment.
文摘Titania microspheres were synthesized using hydrothermal methods to exploit a new liquid chromatography stationary phase. The prepared titania microspheres were approximately 7 μm in diameter, and the particle size distribution was relatively narrow and uniform. Furthermore, the average specific surface area was 276.0 m2·g·1, the average pore volume was approximately 0.25 mL·g·1, and the pore diameter was approximately 35.9 nm for sintering titania microspheres. These parameters indicate that the titania microspheres prepared for this study have excellent surface properties for chromatography. Additionally, columns filled with the titania microspheres were able to separate basic compounds, including benzene, nitrobenzene and o-nitroanisole. It could be proposed that the titania microspheres prepared for this study would be a promising stationary phase for liquid chromatography.
基金sponsored by the Natural Science Foundation of China(Nos.22371126,21776139 and 22072067)the“Qing Lan Project”Young and Middle-aged Academic Leaders of Jiangsu Provincial Colleges and Universities,the Natural Science Foundation of Jiangsu Province(No.BK20161553)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Practical,undirected and selective catalytic functionalization of unactivated arenes remains a challenging problem in organic synthesis.We herein report a bioinspired L-cystine-derived ligand BCPOM/Fe-enabled innate C-H difluoromethylation of unactivated arenes as limiting reagents with stable and inexpensive BrCF_(2)CO_(2)Et as the difluoromethylation source in high efficiency.Notably,this method uses environmentally benign H_(2)O_(2) as the sole oxidant,and enables late-stage functionalization and exceptionally functional-group tolerance,even including oxidation-labile aldehyde,phenolic hydroxy,primary amine,and boronic acid groups,which is difficult to access by current means.
基金supported by the National Natural Science Foundation of China(22374077,22474059,and 22308319)the Priority Academic Program Development of Jiangsu Higher Education InstitutionsThis work was carried out with the support of BL17B1 at the Shanghai Synchrotron Radiation Facility(proposal 2023-NFPS-PT-500772).
文摘Mass transport processes across multiple length scales underpin a wide range of natural phenomena and technological applications.Among them,the chimney effect,widely observed at the macroscopic scale,refers to the convective flow induced by density differences within a hollow channel,where warm air rises and cooler air flows in to replace it,creating a natural pressure difference[1,2].This effect has been extensively harnessed in diverse applications,including solar chimney power plants,building ventilation systems,and photothermal evaporation platforms[3,4].
基金supported by the National Natural Science Foundation of China for the project(Nos.52201222,22234005,and 21974070)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Niobium oxide(Nb_(2)O_(5))is a promising material in photocatalytic,solar cell,electronic like electron field emitters,and especially lithium-ion batteries(LIBs)because of its adjustable morphologies,controllable crystal type,stable structure,and environmental friendliness.However,its low electrical conductivity lowers the rate performance and limits the practical applications in LIBs.Herein,we present a one-step solid-state synthesis of orthogonal Nb_(2)O_(5) nanocrystals/graphene composites(Nb_(2)O_(5)/G)as high-performance anode materials in LIBs.Benefiting from the nanoscale crystalline structure Nb_(2)O_(5) and highly-conductive graphene substrate,the as-prepared Nb_(2)O_(5)/G exhibits excellent electrochemical performances.Impressively,a reversible structural phase transition between orthogonal Nb_(2)O_(5) and tetragonal Li1-xNbO_(2)(0<x<1)was verified by ex-situ transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).After coupling with graphite cathode based on PF6-intercalation/deintercalation mechanisms,Nb_(2)O_(5)/G||graphite dual-ion batteries(DIBs)full cell delivers good electrochemical performance in terms of cyclic performance and rate capability.We believe this work can provide a clear route towards developing advanced transition metal oxide/graphene composite anode and a comprehension of its electrochemical reaction mechanism.
基金supported by the National Natural Science Foundation of China(grant nos.22234005 and 22074064)the Jiangsu Province’s Innovation Program(grant no.JSSCTD202142)+1 种基金The authors extend their appreciation to the financial support from the Young Science and Technology Talents Promotion Project of Jiangsu Science and Technology Association(grant no.JSTJ20201116)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Analyzing single organelles within the intricate compartmentalizedsystems of eukaryotic cells poses significantchallenges in biomedical research. Presently,assessment of organelle functions frequently relies onthe disjointed application of multiple techniques, resultingin constraints on the promptness and precision ofdata acquisition. Herein, a dual-nanopore electrochemicalbiosensor has been designed in this work to housedetection channels directly in living cells for in situ andconcurrent acquisition of multiple key characteristicsof a single mitochondrion. In one channel, mitochondrialreactive oxygen species (ROS) and associated adenosinetriphosphate (ATP) production are electrochemicallymeasured with a redox activatable probe(Apt-MB), while the parallel channel facilitates the measurementof mitochondrial ΔΨm via proton responsiveness.Quantitative assessment of the relationshipbetween ROS and ΔΨm against ATP production hasbeen achieved, which allows in-depth analysis of mitochondrialfunctions. With this approach, the resultsclearly show evolutionary stages of the apoptosis pathway,and highlight that mitochondrial proton circuitdecoupling may serve as an earlier event preceding thewell-known ROS accumulation stage. Hence, this studyunderscores the considerable usage of this approachfor comprehensive analysis of single mitochondrialfunctionality, and may further inspire the developmentof micro/nanoscale tools for multiparameter, high-fidelity,single-organelle analysis directly within cells.
基金supported by the National Natural Science Foundation of China(21671106,22102073,and 62288102)the Priority Academic Program Development of Jiangsu Higher Education Institutions,the funding from Minjiang Scholars Award Program(2023)+1 种基金the Start-Up Fund for High-Leveled Talents from Fujian Normal University(Y0720316K13)the opening research foundations of the State Key Laboratory of Coordination Chemistry,Nanjing National Laboratory of Solid State Microstructures,Nanjing University.We thank the BL14W1 beamlines for XAFS tests at the Shanghai Synchrotron Radiation Facility(SSRF)(Shanghai,China).
文摘Overall seawater splitting driven by regenerable electricity is an ideal pathway formass production of green hydrogen.Nonetheless,its anodic oxygen evolution half-reaction(OER)confronts sluggish kinetics,competitive chlorine evolution,and chloride corrosion or poisoning problems,needing to develop high-efficient and robust electrocatalysts toward those challenges.Herein,novel defect-rich single-phase(NiCoMnCrFe)_(3)O_(4) high-entropy spinel oxide(HEO)is fabricated by low-temperature annealing of highentropy layered double hydroxide precursor.Due to the presence of abundant defects,unique“cocktail”effect,and efficient electronic structure regulation,such(NiCoMnCrFe)_(3)O_(4) can deliver 500 mA cm^(−2) current density at the overpotentials of 268/384 mV in alkaline freshwater/seawater,outperforming its counterparts,commercial IrO_(2),and most reported OER catalysts.Moreover,it manifests exceptional OER durability and anticorrosion capability.Theoretical calculations reveal that the eg occupancies of surface Mn atoms are closer to 1.0,which may be the activity origin of such HEO.Importantly,the constructed(NiCoMnCrFe)_(3)O_(4)||Pt/C electrolyzer only requires 1.57 V cell voltage for driving overall seawater splitting to reach 500 mA cm^(−2) current under real industrial conditions.This work may spur the development of advanced OER electrocatalysts by combining entropy and defect engineering and accelerate their applications in seawater splitting,metal–air batteries,or marine biomass electrocatalytic conversion fields.
基金supported by the National Institutes of Health(K01 AR07787,R21 R077700,P30 AR069619,R01 AR056624,R01 HL163168)National Science Foundation(CMMI 1548571)+2 种基金Department of Veterans Affairs(CReATE Motion Center,I50 RX004845)in the United Statessupported by the Korea Health Technology R&D Project through the Korea Health Industry Develop-ment Institute(KHIDI)funded by the Ministry of Health and Welfare(HI19C1095)National R&D Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(RS-2024-00405574)in the Republic of Korea.
文摘Meniscus injuries present significant therapeutic challenges due to their limited self-healing capacity and the diverse biological and mechanical properties across the tissue.Conventional repair strategies do not replicate the complex zonal characteristics within the meniscus,resulting in suboptimal outcomes.In this study,we introduce an innovative fetal/adult and stiffness-tunable meniscus decellularized extracellular matrix(DEM)-based hydrogel system designed for precision repair of heterogeneous,zonal-dependent meniscus injuries.By syn-thesizing fetal and adult DEM hydrogels,we identified distinct cellular responses,including that hydrogels with adult meniscus-derived DEM promote more fibrochondrogenic phenotypes.The incorporation of methacrylated hyaluronic acid(MeHA)further refined the mechanical properties and injectability of the DEM-based hydrogels.The combination of fetal and adult DEM with MeHA allowed for precise tuning of stiffness,influencing cell differentiation and closely mimicking native tissue environments.In vivo tests confirmed the biocompatibility of hydrogels and their integration with native meniscus tissues.Furthermore,advanced 3D bioprinting techniques enabled the fabrication of hybrid hydrogels with biomaterial and mechanical gradients,effectively emulating the zonal properties of meniscus tissue and enhancing cell integration.This study represents a significant advance in meniscus tissue engineering,providing a promising platform for customized regenerative therapies across a range of heterogeneous fibrous connective tissues.
基金support from the National Natural Science Foundation of China(Grant Nos.20875046,20871070&20901041)
文摘This paper reports a simple method for immobilization of acetylcholinesterase(AChE)on one-dimensional(1D)gold(Au)nanoparticles for detection of organophosphorous(OP)insecticides.1D Au nanoparticles were prepared by electrodeposition in the pores of an alumina template which was subsequently removed by 2.0 M NaOH solution.They were characterized by XRD and FESEM.The immobilized AChE retained its biological activity and catalyzed the hydrolysis of acetylthiocholine to form thiocholine,which was subsequently oxidized to produce detectable signals.Based on the inhibition toward the enzymatic activity of AChE by OP insecticides,sensitive detection of methamidophos(an OP insecticide)was performed.Under optimal conditions,the sensors could be used for the determination of methamidophos ranging from 0.004 to 24μg/mL with the detection limit of 0.001μg/mL.The developed OP insecticide biosensors exhibited satisfactory stability and reproducibility.This work demonstrated that 1D Au nanoparticles could serve as an ideal carrier for immobilization of AChE to fabricate the corresponding biosensor.
