In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]...In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]^(2-)species on Fe_(2)O_(3) nanorod array followed by the hydrolysis in alkaline solution.The resulting CoOOH/Fe_(2)O_(3) exhibits a remarkably improved photocurrent density of 2.10 mA cm^(-2) at 1.23 V vs.RHE,which is ca.2.8 times that of bare Fe_(2)O_(3).In addition,a negative shift of onset potential ca.200 mV is achieved.The structural characterizations reveal the chelate EDTA plays important roles that enhance the adsorption of Co species and the formation of contact between CoOOH and Fe_(2)O_(3).(Photo)electrochemical analysis suggests,besides providing active sites for water oxidation,CoOOH at large extent promotes the charge separation and the charge transfer via passivating surface states and suppressing charge recombination.It also found CoOOH possesses some oxygen vacancies,which could act as trapping centers for photogenerated holes and facilitate the charge separation.Intensity modulated photocurrent spectroscopy(IMPS)shows that,under low applied potential the water oxidation mainly occurs on CoOOH,while under high applied potential the water oxidation could occur on both CoOOH and Fe_(2)O_(3).The findings not only provide an efficient strategy for designing ultrathin(oxy)hydroxides on semiconductors for PEC applications but also put forward a new insight on the role of CoOOH during water oxidation.展开更多
Carbon and oxygen-rich corrosion barrier layer formed on Mg by a simple and scalable CO_(2) atmospheric plasma(CO_(2)-AP)process.The reactive CO_(2)-AP interacts with the Mg surface and forms a unique layered structur...Carbon and oxygen-rich corrosion barrier layer formed on Mg by a simple and scalable CO_(2) atmospheric plasma(CO_(2)-AP)process.The reactive CO_(2)-AP interacts with the Mg surface and forms a unique layered structure with the top MgCO_(3)/MgO-intermixed particulates pillars and the bottom dense layer.The surface features were simultaneously formed on the nano-/micro-structured MgO layer by carbonate molecules,plasma-active CO_(2) molecules,and/or other volatile organic compounds on the nano-/micro-structured MgO particle layer.The resulting surfaces after CO_(2)-AP were either hydrophobic or hydrophilic and exhibited lower anodic current or high resistance for Mg corrosion.For the hydrophobic surfaces of CO_(2)-AP treated Mg,molecular dynamic simulations were performed to understand the origin of hydrophobicity and identified that the amorphous carbon layers formed on the Mg surface are the source.The environmentally benign abundant-gas-based process enables the cost reduction associated with waste treatment,generation of by-product,and supply of raw material.展开更多
Phosphorylated mesoporous carbons (PMCs) were investigated as catalysts in the dehydration of fructose to hydroxymethylfurfural (HMF). The acidic PMCs show better selectivity to HMF compared to sulfonated carbon c...Phosphorylated mesoporous carbons (PMCs) were investigated as catalysts in the dehydration of fructose to hydroxymethylfurfural (HMF). The acidic PMCs show better selectivity to HMF compared to sulfonated carbon catalyst (SC) despite lower activity. The concentration of P-O groups on the PMC was correlated with the activity/selectivity of the catalysts; the higher the P-O concentration, the higher the activity. However, the higher the P-O content, the lower the selectivity to HME Indeed, a lower concentration of the P-O groups minimized the degradation of HMF to levulinic acid and the formation of by-products, such as humines. Stability tests showed that these systems deactivate due to the formation of humines and water insoluble by-products derived from the dehydration of fructose which blocked the catalytically active sites.展开更多
Electron beam curing is demonstrated as a promising method for high speed,low cost and environmentally friendly battery electrode manufacturing.This work reports transfer of this process to pilot scale equipment and e...Electron beam curing is demonstrated as a promising method for high speed,low cost and environmentally friendly battery electrode manufacturing.This work reports transfer of this process to pilot scale equipment and evaluation of electrochemical performance in prototype 1.5 Ah pouch cells.Thick LiNi0.5Mn0.3Co0.2O2(NMC532)composite electrodes with an areal loading of 25 mg cm^-2(~4 mAh cm^-2)are successfully cured at a line speed of 500 feet per minute at 275 keV.Compared to the NMC532 cathode processed via a conventional coating method,the electron beam cured electrodes show higher capacity fade in the first 100 cycles,but similar fade rate afterwards.Further improvement strategies are proposed and discussed.This work demonstrates that electron beam curing is a promising method for manufacturing thick battery electrodes at high speeds and low capital/operation cost.展开更多
Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs ...Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs is still plagued by the low specific capacity and poor rate capability.Herein,highly crystalline Mn2O3 materials with interconnected mesostructures and controllable pore sizes are obtained via a ligand-assisted self-assembly process and used as high-performance electrode materials for reversible aqueous ZIBs.The coordination degree between Mn2+and citric acid ligand plays a crucial role in the formation of the mesostructure,and the pore sizes can be easily tuned from 3.2 to 7.3 nm.Ascribed to the unique feature of nanoporous architectures,excellent zinc-storage performance can be achieved in ZIBs during charge/discharge processes.The Mn2O3 electrode exhibits high reversible capacity(233 mAh g−1 at 0.3 A g−1),superior rate capability(162 mAh g−1 retains at 3.08 A g−1)and remarkable cycling durability over 3000 cycles at a high current rate of 3.08 A g−1.Moreover,the corresponding electrode reaction mechanism is studied in depth according to a series of analytical methods.These results suggest that rational design of the nanoporous architecture for electrode materials can effectively improve the battery performance.展开更多
Posttranslational modifications of antibody products affect their stability,charge distribution,and drug activity and are thus a critical quality attribute.The comprehensive mapping of antibody modifications and diffe...Posttranslational modifications of antibody products affect their stability,charge distribution,and drug activity and are thus a critical quality attribute.The comprehensive mapping of antibody modifications and different charge isomers(CIs)is of utmost importance,but is challenging.We intended to quantitatively characterize the posttranslational modification status of CIs of antibody drugs and explore the impact of posttranslational modifications on charge heterogeneity.The CIs of antibodies were fractionated by strong cation exchange chromatography and verified by capillary isoelectric focusing-whole column imaging detection,followed by stepwise structural characterization at three levels.First,the differences between CIs were explored at the intact protein level using a top-down mass spectrometry approach;this showed differences in glycoforms and deamidation status.Second,at the peptide level,common modifications of oxidation,deamidation,and glycosylation were identified.Peptide mapping showed nonuniform deamidation and glycoform distribution among CIs.In total,10 N-glycoforms were detected by peptide mapping.Finally,an in-depth analysis of glycan variants of CIs was performed through the detection of enriched glycopeptides.Qualitative and quantitative analyses demonstrated the dynamics of 24 N-glycoforms.The results revealed that sialic acid modification is a critical factor accounting for charge heterogeneity,which is otherwise missed in peptide mapping and intact molecular weight analyses.This study demonstrated the importance of the comprehensive analyses of antibody CIs and provides a reference method for the quality control of biopharmaceutical analysis.展开更多
High-quality graphene flakes have long been desirable for numerous applications including energy stor- age, printable electronics, and catalysis. In this contribution, we report a green, efficient, facile gas-driven e...High-quality graphene flakes have long been desirable for numerous applications including energy stor- age, printable electronics, and catalysis. In this contribution, we report a green, efficient, facile gas-driven exfoliation process for the preparation of high-quality graphene in large scale. The gas exfoliation process was realized by the interplay between the expansion of interlayer at high temperature and the gasifi- cation of liquid nitrogen within the interlayer. Detailed experiments demonstrated that the higher tem- perature was critical to the formation of fewer layers. The exfoliated graphene was proved to be of high quality. We further investigated the electrochemical behavior of this exfoliated graphene. As a result, this few-layered graphene demonstrated an enhanced capability as a supercapacitor, much higher than its counterpart parent material.展开更多
Ni_xWO_(2.72) nanorods(NRs) are synthesized by a one-pot reaction of Ni(acac)_2 and WCl_4. In the rod structure, Ni(Ⅱ) intercalates in the defective perovskite-type WO_(2.72) and is stabilized. The Ni_xWO_(2.72) NRs ...Ni_xWO_(2.72) nanorods(NRs) are synthesized by a one-pot reaction of Ni(acac)_2 and WCl_4. In the rod structure, Ni(Ⅱ) intercalates in the defective perovskite-type WO_(2.72) and is stabilized. The Ni_xWO_(2.72) NRs show the x-dependent electrocatalysis for the oxygen evolution reaction(OER) in 0.1 M KOH with Ni_(0.78)WO_(2.72) being the most efficient, even outperforming the commercial Ir-catalyst. The synthesis is not limited to Ni_xWO_(2.72) but can be extended to M_xWO_(2.72)(M = Co, Fe) as well,providing a new class of oxide-based catalysts for efficient OER and other energy conversion reactions.展开更多
Activation and surface reactions of CO and H2 on ZnO powders and nanoplates under CO hydrogenation reaction conditions were(quasi) in situ studied using temperature programmed surface reaction spectra, diffuse reflect...Activation and surface reactions of CO and H2 on ZnO powders and nanoplates under CO hydrogenation reaction conditions were(quasi) in situ studied using temperature programmed surface reaction spectra, diffuse reflectance Fourier transform infrared spectroscopy, inelastic neutron scattering spectroscopy and electron paramagnetic resonance. CO undergoes disproportion reaction to produce gaseous CO2 and surface carbon adatoms, and adsorbs to form surface formate species. H2 adsorption forms dominant irreversibly-adsorbed surface hydroxyl groups and interstitial H species and very minor surface Zn-H species. Surface formate species and hydroxyl groups react to produce CO2 and H2, while surface carbon adatoms are hydrogenated by surface Zn-H species sequentially to produce CH(a), CH2(a), CH3(a)and eventually gaseous CH4. The ZnO nanoplates, exposing a higher fraction of Zn-ZnO(0001) and OZnO(000–1) polar facets, are more active than the ZnO powders to catalyze CO hydrogenation to CH4.These results provide fundamental understanding of the reaction mechanisms and structural effects of CO hydrogenation reaction catalyzed by ZnO-based catalysts.展开更多
High-temperature phases of solids are often dynamically stable only.First-principles study of point defects in such solids at 0 K is prohibited by their static instability,which results in random structures of the def...High-temperature phases of solids are often dynamically stable only.First-principles study of point defects in such solids at 0 K is prohibited by their static instability,which results in random structures of the defect-containing supercell so that the total energy of the supercell is randomly affected by structural distortions far away from the defect.Taking cubic perovskiteα-Cs Pb I_(3) as an example,we first present the problem incurred by the static instability and then propose an approach based on molecular dynamics to carry out ensemble average for tackling the problem.Within affordable simulation time,we obtain converged defect ionization energies,which are unattainable by a standard approach and allow us to evaluate its defect tolerance property.Our work paves the way for studying defects in statically unstable solids.展开更多
The cathode of biofuel cell reduces molecular oxygen to water using four electrons, an enzyme of multicopper oxidase family, laccase, is contained, though its electron transfer efficiency from the electrode resulted i...The cathode of biofuel cell reduces molecular oxygen to water using four electrons, an enzyme of multicopper oxidase family, laccase, is contained, though its electron transfer efficiency from the electrode resulted in rate determining process. To improve this electron, transfer via mediators, we have investigated several mediator metal complexes between the electrode and laccase, in particular hydrophobic pocket on the surface. We have discussed DFT computational results and selected experimental data of new Mn(III/II) Schiff base complexes having redox active (anthraquinone) ligands and photochromic (azobenzene) ligands about azobenzene moiety at the sole molecular level. Moreover, we carried out computational docking simulation of laccase and complexes considering trans-cis photoisomerization (electronic states) and Weigert effect (molecular orientation to fit better) of azobenzene moiety. Additionally, actual experimental data also presented to indicate the expected merits for mediators.展开更多
Mechanochemistry has been recognized as an efficient and sustainable methodology to provide a unique driven force and reaction environments under ambient and neat conditions for the construction of functionalized mate...Mechanochemistry has been recognized as an efficient and sustainable methodology to provide a unique driven force and reaction environments under ambient and neat conditions for the construction of functionalized materials possessing promising properties.Among them,highly porous conjugated scaffolds with attractive electronic conductivities and high surface areas are one of the representative categories exhibiting diverse taskspecific applications,especially in electrochemical energy storage.In recent years,the mechanochemistry-driven procedures have been deployed to construct conjugated scaffolds with engineered structures and properties leveraging the tunability in chemical structures of building blocks and polymerization capability of diverse catalysts.Therefore,a thorough review of related works is required to gain an in-depth understanding of the mechanochemical synthesis procedure and property-performance relationship of the as-produced conjugated scaffolds.Herein,the mechanochemistry-driven construction of conjugated porous networks(CPNs),the carbon-based materials(e.g.,graphite and graphyne),and carbon supported single atom catalysts(CS-SACs)are discussed and summarized.The electrochemical performance of the afforded conductive scaffolds as electrode materials in supercapacitors and alkali-ion batteries is elucidated.Finally,the challenges and potential opportunities related to the construction of conjugated scaffolds driven by mechanochemistry are also discussed and concluded.展开更多
Herein,we report the synthesis and structures of two novel mixed-metal clusters denoted as Th_(9)Ag_(6)and Th_(9)Ag_(12).Both clusters feature unprecedented Th_(9)cores.The cores are tricapped trigonal prism moieties ...Herein,we report the synthesis and structures of two novel mixed-metal clusters denoted as Th_(9)Ag_(6)and Th_(9)Ag_(12).Both clusters feature unprecedented Th_(9)cores.The cores are tricapped trigonal prism moieties that are novel among actinides.Attempted alternative synthesis routes indicate that the Th_(9)clusters are accessible only through slow introduction of Ag_(+)into a solution containing a Th6 cluster modified with 2-picolinic acid.Alternative rapid addition of Ag_(+)leads to dissociation of the Th6 cluster with formation of a high-purity(ThAg)_(∞)two-dimensional layered structure material.A mechanism for cluster dissociation and reassembly to yield Th_(9)from Th6 is proposed that is consistent with spectroscopic observations and computational results.Because of Ag⋯Ag andπ–πinteractions,the Th_(9)Ag_(12)cluster exhibits high stability in air,at elevated temperature,underγ-irradiation,and in common solvents.展开更多
Organic moieties-derived salts with permanent porosity and polarized channels have shown unique features and attractive performance in the field of adsorption,separation,and conduction.However,state-of-the-art organic...Organic moieties-derived salts with permanent porosity and polarized channels have shown unique features and attractive performance in the field of adsorption,separation,and conduction.However,state-of-the-art organic salts generally rely on ionic interaction and hydrogen bonding formation to maintain the porous channels.The synthesis of organic moiety-derived saltswith permanent accessible pores even after removal of the trapped guest molecules,and without the constraint of hydrogen bonding formation still remains a great challenge.Herein,we present an expeditious construction pathway to generate hierarchically nanoporous barium salts without hydrogen bonding formation.The strong ionic interaction of the bariumcation and sulfonate anions led to rapid reaction equilibrium(∼2 min),affording diverse barium-derived ionic polymer(Ba-IP)with permanent porosity and highly polarized channels.The produced Ba-IP materials with abundant cations and anions displayed high CO_(2)/N2 and CO_(2)/CH_(4)separation performance,with the selectivities reaching up to 89.5 and 280,respectively,at 273 K,surpassingmost of the organic polymers functionalized by ionic moieties.展开更多
Dynamic polymers with both physical interactions and dynamic covalent bonds exhibit superior performance,but achieving such dry polymers in an effi-cient manner remains a challenge.Herein,we report a novel organic sol...Dynamic polymers with both physical interactions and dynamic covalent bonds exhibit superior performance,but achieving such dry polymers in an effi-cient manner remains a challenge.Herein,we report a novel organic solvent quenched polymer synthesis using the natural molecule thioctic acid(TA),which has both a dynamic disulfide bond and carboxylic acid.The effects of the solvent type and concentration along with reaction times on the proposed reaction were thoroughly explored for polymer synthesis.Solid-state proton nuclear magnetic resonance(1 H NMR)and first-principles simulations were carried out to investigate the reaction mechanism.They show that the chlorinated solvent can efficiently stabilize and mediate the depolymerization of poly(TA),which is more kinetically favorable upon lowering the temperature.Attributed to the numerous dynamic covalent disulfide bonds and noncovalent hydrogen bonds,the obtained poly(TA)shows high extensibility,self-healing,and reprocessable properties.It can also be employed as an efficient adhesive even on a Teflon surface and 3D printed using the fused deposition modeling technique.This new polymer synthesis approach of using organic solvents as catalysts along with the unique reaction mechanism provides a new pathway for efficient polymer synthesis,especially for multifunctional dynamic polymers.展开更多
Polymer-coated mesoporous carbon nanocomposites were prepared from the immobilization of acrylonitrile and acrylic acid copolymers with divinylbenzene as a crosslinker onto a mesoporous carbon framework.High surface a...Polymer-coated mesoporous carbon nanocomposites were prepared from the immobilization of acrylonitrile and acrylic acid copolymers with divinylbenzene as a crosslinker onto a mesoporous carbon framework.High surface areas were maintained after polymerization with accessible porosity.This functional nanocomposite was tested as an adsorbent for uranium from high salinity solutions.Uranium adsorption results have shown that the adsorption capacities are strongly influenced by the density of the amidoxime groups and the specific surface area.展开更多
基金supported by the National Natural Science Foundation of China(51502078)the Major Project of Science and Technology,Education Department of Henan Province(19A150019 and 19A150018)+2 种基金the Science and Technology Research Project of Henan Province(192102310490 and 182102410090)the program for Science&Technology Innovation Team in Universities of Henan Province(19IRTSTHN029)supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Chemical Sciences,Geosciences,and Biosciences Division,Catalysis Science program。
文摘In this work,a facile chelation-mediated route was developed to fabricate ultrathin cobalt(oxy)hydroxides(CoOOH)nanosheets on hematite photoanode(Fe_(2)O_(3)).The route contains two steps of the adsorption of[Co-EDTA]^(2-)species on Fe_(2)O_(3) nanorod array followed by the hydrolysis in alkaline solution.The resulting CoOOH/Fe_(2)O_(3) exhibits a remarkably improved photocurrent density of 2.10 mA cm^(-2) at 1.23 V vs.RHE,which is ca.2.8 times that of bare Fe_(2)O_(3).In addition,a negative shift of onset potential ca.200 mV is achieved.The structural characterizations reveal the chelate EDTA plays important roles that enhance the adsorption of Co species and the formation of contact between CoOOH and Fe_(2)O_(3).(Photo)electrochemical analysis suggests,besides providing active sites for water oxidation,CoOOH at large extent promotes the charge separation and the charge transfer via passivating surface states and suppressing charge recombination.It also found CoOOH possesses some oxygen vacancies,which could act as trapping centers for photogenerated holes and facilitate the charge separation.Intensity modulated photocurrent spectroscopy(IMPS)shows that,under low applied potential the water oxidation mainly occurs on CoOOH,while under high applied potential the water oxidation could occur on both CoOOH and Fe_(2)O_(3).The findings not only provide an efficient strategy for designing ultrathin(oxy)hydroxides on semiconductors for PEC applications but also put forward a new insight on the role of CoOOH during water oxidation.
基金the US Department of Energy’s(DOE’s)Office of Energy Efficiency and Renewable Energy,Vehicle Technology Office,Powertrain Materials Core and Light Metals Core ProgramsSample characterization is also partially supported by the Technology Commercialization Fund Fiscal Year 2020 of DOE’s Office of Technology Transitionsby the Creative Materials Discovery Program through the National Research Foundation of Korea,with computational modeling of amorphous carbons funded by the Ministry of Science,ICT and Future Planning(NRF-2016M3D1A1919181)。
文摘Carbon and oxygen-rich corrosion barrier layer formed on Mg by a simple and scalable CO_(2) atmospheric plasma(CO_(2)-AP)process.The reactive CO_(2)-AP interacts with the Mg surface and forms a unique layered structure with the top MgCO_(3)/MgO-intermixed particulates pillars and the bottom dense layer.The surface features were simultaneously formed on the nano-/micro-structured MgO layer by carbonate molecules,plasma-active CO_(2) molecules,and/or other volatile organic compounds on the nano-/micro-structured MgO particle layer.The resulting surfaces after CO_(2)-AP were either hydrophobic or hydrophilic and exhibited lower anodic current or high resistance for Mg corrosion.For the hydrophobic surfaces of CO_(2)-AP treated Mg,molecular dynamic simulations were performed to understand the origin of hydrophobicity and identified that the amorphous carbon layers formed on the Mg surface are the source.The environmentally benign abundant-gas-based process enables the cost reduction associated with waste treatment,generation of by-product,and supply of raw material.
基金supported by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle,LLC, for the U. S. Department of Energy (GMV). TEM studies were performed through Oak Ridge National Laboratory’s Center for Nanophase Materials Science (CNMS) which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U. S. Department of Energy
文摘Phosphorylated mesoporous carbons (PMCs) were investigated as catalysts in the dehydration of fructose to hydroxymethylfurfural (HMF). The acidic PMCs show better selectivity to HMF compared to sulfonated carbon catalyst (SC) despite lower activity. The concentration of P-O groups on the PMC was correlated with the activity/selectivity of the catalysts; the higher the P-O concentration, the higher the activity. However, the higher the P-O content, the lower the selectivity to HME Indeed, a lower concentration of the P-O groups minimized the degradation of HMF to levulinic acid and the formation of by-products, such as humines. Stability tests showed that these systems deactivate due to the formation of humines and water insoluble by-products derived from the dehydration of fructose which blocked the catalytically active sites.
基金sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO) (Deputy Director: David Howell) Applied Battery Research subprogram (Program Manager: Peter Faguy)
文摘Electron beam curing is demonstrated as a promising method for high speed,low cost and environmentally friendly battery electrode manufacturing.This work reports transfer of this process to pilot scale equipment and evaluation of electrochemical performance in prototype 1.5 Ah pouch cells.Thick LiNi0.5Mn0.3Co0.2O2(NMC532)composite electrodes with an areal loading of 25 mg cm^-2(~4 mAh cm^-2)are successfully cured at a line speed of 500 feet per minute at 275 keV.Compared to the NMC532 cathode processed via a conventional coating method,the electron beam cured electrodes show higher capacity fade in the first 100 cycles,but similar fade rate afterwards.Further improvement strategies are proposed and discussed.This work demonstrates that electron beam curing is a promising method for manufacturing thick battery electrodes at high speeds and low capital/operation cost.
基金the Young Thousand Talented Program and the National Natural Science Foundation of China (21671073 and 21621001)the “111” Project of the Ministry of Education of China (B17020)Program for JLU Science and Technology Innovative Research Team
文摘Manganese oxides are regarded as one of the most promising cathode materials in rechargeable aqueous Zn-ion batteries(ZIBs)because of the low price and high security.However,the practical application of Mn2O3 in ZIBs is still plagued by the low specific capacity and poor rate capability.Herein,highly crystalline Mn2O3 materials with interconnected mesostructures and controllable pore sizes are obtained via a ligand-assisted self-assembly process and used as high-performance electrode materials for reversible aqueous ZIBs.The coordination degree between Mn2+and citric acid ligand plays a crucial role in the formation of the mesostructure,and the pore sizes can be easily tuned from 3.2 to 7.3 nm.Ascribed to the unique feature of nanoporous architectures,excellent zinc-storage performance can be achieved in ZIBs during charge/discharge processes.The Mn2O3 electrode exhibits high reversible capacity(233 mAh g−1 at 0.3 A g−1),superior rate capability(162 mAh g−1 retains at 3.08 A g−1)and remarkable cycling durability over 3000 cycles at a high current rate of 3.08 A g−1.Moreover,the corresponding electrode reaction mechanism is studied in depth according to a series of analytical methods.These results suggest that rational design of the nanoporous architecture for electrode materials can effectively improve the battery performance.
基金the financial support from the National Key Program for Basic Research of China(Grant Nos.:2018YFC0910302 and 2017YFF0205400)the National Natural Science Foundation of China(Grant No.:81530021)Innovation Foundation of Medicine(Grant Nos.:BWS14J052 and 16CXZ027)
文摘Posttranslational modifications of antibody products affect their stability,charge distribution,and drug activity and are thus a critical quality attribute.The comprehensive mapping of antibody modifications and different charge isomers(CIs)is of utmost importance,but is challenging.We intended to quantitatively characterize the posttranslational modification status of CIs of antibody drugs and explore the impact of posttranslational modifications on charge heterogeneity.The CIs of antibodies were fractionated by strong cation exchange chromatography and verified by capillary isoelectric focusing-whole column imaging detection,followed by stepwise structural characterization at three levels.First,the differences between CIs were explored at the intact protein level using a top-down mass spectrometry approach;this showed differences in glycoforms and deamidation status.Second,at the peptide level,common modifications of oxidation,deamidation,and glycosylation were identified.Peptide mapping showed nonuniform deamidation and glycoform distribution among CIs.In total,10 N-glycoforms were detected by peptide mapping.Finally,an in-depth analysis of glycan variants of CIs was performed through the detection of enriched glycopeptides.Qualitative and quantitative analyses demonstrated the dynamics of 24 N-glycoforms.The results revealed that sialic acid modification is a critical factor accounting for charge heterogeneity,which is otherwise missed in peptide mapping and intact molecular weight analyses.This study demonstrated the importance of the comprehensive analyses of antibody CIs and provides a reference method for the quality control of biopharmaceutical analysis.
基金supported by the U.S.Department of Energy’s Office of Basic Energy Science,Division of Materials Sciences and Engineering,under contract with UT-Battelle,LLC
基金the China National Natural Science Foundation of China (Nos. 21722604, 21576122, 21376111)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)+1 种基金a scholarship from the China Scholarship Council (CSC)the Postgraduate Innovation Project of Jiangsu Province (NO. KYLX15_1067)
文摘High-quality graphene flakes have long been desirable for numerous applications including energy stor- age, printable electronics, and catalysis. In this contribution, we report a green, efficient, facile gas-driven exfoliation process for the preparation of high-quality graphene in large scale. The gas exfoliation process was realized by the interplay between the expansion of interlayer at high temperature and the gasifi- cation of liquid nitrogen within the interlayer. Detailed experiments demonstrated that the higher tem- perature was critical to the formation of fewer layers. The exfoliated graphene was proved to be of high quality. We further investigated the electrochemical behavior of this exfoliated graphene. As a result, this few-layered graphene demonstrated an enhanced capability as a supercapacitor, much higher than its counterpart parent material.
基金supported by the U.S.Army Research Laboratory and the U.S. Army Research Office under grant W911NF-15-1-0147 on "New Composite Catalysts Based on Nitrogen-Doped Graphene and Nanoparticles for Advanced Electrocatalysis"Part of electron microscopy work used resources of the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704
文摘Ni_xWO_(2.72) nanorods(NRs) are synthesized by a one-pot reaction of Ni(acac)_2 and WCl_4. In the rod structure, Ni(Ⅱ) intercalates in the defective perovskite-type WO_(2.72) and is stabilized. The Ni_xWO_(2.72) NRs show the x-dependent electrocatalysis for the oxygen evolution reaction(OER) in 0.1 M KOH with Ni_(0.78)WO_(2.72) being the most efficient, even outperforming the commercial Ir-catalyst. The synthesis is not limited to Ni_xWO_(2.72) but can be extended to M_xWO_(2.72)(M = Co, Fe) as well,providing a new class of oxide-based catalysts for efficient OER and other energy conversion reactions.
基金the National Key R&D Program of Ministry of Science and Technology of China(2017YFB0602205)the National Natural Science Foundation of China(21525313,91745202,91945301)+4 种基金the Chinese Academy of Sciencesthe Changjiang Scholars Program of Ministry of Education of Chinathe financial support of the China Scholarship Councilsupported by the Scientific User Facilities Division,Office of Basic Energy Sciences,US DOE,under Contract No.DE-AC0500OR22725 with UT Battelle,LLCsupported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Chemical Sciences,Geosciences,and Biosciences Division,Catalysis Science Program。
文摘Activation and surface reactions of CO and H2 on ZnO powders and nanoplates under CO hydrogenation reaction conditions were(quasi) in situ studied using temperature programmed surface reaction spectra, diffuse reflectance Fourier transform infrared spectroscopy, inelastic neutron scattering spectroscopy and electron paramagnetic resonance. CO undergoes disproportion reaction to produce gaseous CO2 and surface carbon adatoms, and adsorbs to form surface formate species. H2 adsorption forms dominant irreversibly-adsorbed surface hydroxyl groups and interstitial H species and very minor surface Zn-H species. Surface formate species and hydroxyl groups react to produce CO2 and H2, while surface carbon adatoms are hydrogenated by surface Zn-H species sequentially to produce CH(a), CH2(a), CH3(a)and eventually gaseous CH4. The ZnO nanoplates, exposing a higher fraction of Zn-ZnO(0001) and OZnO(000–1) polar facets, are more active than the ZnO powders to catalyze CO hydrogenation to CH4.These results provide fundamental understanding of the reaction mechanisms and structural effects of CO hydrogenation reaction catalyzed by ZnO-based catalysts.
基金supports from Shanghai International Cooperation Project(Grant No.20520760900)the Major Science and Technology Programs of Yunnan(Grant No.202002AB080001-1)+2 种基金supports from the Natural Science Foundation of Shanghai(Grant No.19ZR1421800)supports from the US National Science Foundation(Grant No.CBET-1510948)Part of the calculations was conducted at Stampede supercomputer resources at TACC made available by Extreme Science and Engineering Discovery Environment(XSEDE)through Allocation(Grant No.TG-DMR180114),which was supported by US National Science Foundation(Grant No.ACI-1548562)。
文摘High-temperature phases of solids are often dynamically stable only.First-principles study of point defects in such solids at 0 K is prohibited by their static instability,which results in random structures of the defect-containing supercell so that the total energy of the supercell is randomly affected by structural distortions far away from the defect.Taking cubic perovskiteα-Cs Pb I_(3) as an example,we first present the problem incurred by the static instability and then propose an approach based on molecular dynamics to carry out ensemble average for tackling the problem.Within affordable simulation time,we obtain converged defect ionization energies,which are unattainable by a standard approach and allow us to evaluate its defect tolerance property.Our work paves the way for studying defects in statically unstable solids.
文摘The cathode of biofuel cell reduces molecular oxygen to water using four electrons, an enzyme of multicopper oxidase family, laccase, is contained, though its electron transfer efficiency from the electrode resulted in rate determining process. To improve this electron, transfer via mediators, we have investigated several mediator metal complexes between the electrode and laccase, in particular hydrophobic pocket on the surface. We have discussed DFT computational results and selected experimental data of new Mn(III/II) Schiff base complexes having redox active (anthraquinone) ligands and photochromic (azobenzene) ligands about azobenzene moiety at the sole molecular level. Moreover, we carried out computational docking simulation of laccase and complexes considering trans-cis photoisomerization (electronic states) and Weigert effect (molecular orientation to fit better) of azobenzene moiety. Additionally, actual experimental data also presented to indicate the expected merits for mediators.
基金supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,Materials Sciences,and Engineering Division
文摘Mechanochemistry has been recognized as an efficient and sustainable methodology to provide a unique driven force and reaction environments under ambient and neat conditions for the construction of functionalized materials possessing promising properties.Among them,highly porous conjugated scaffolds with attractive electronic conductivities and high surface areas are one of the representative categories exhibiting diverse taskspecific applications,especially in electrochemical energy storage.In recent years,the mechanochemistry-driven procedures have been deployed to construct conjugated scaffolds with engineered structures and properties leveraging the tunability in chemical structures of building blocks and polymerization capability of diverse catalysts.Therefore,a thorough review of related works is required to gain an in-depth understanding of the mechanochemical synthesis procedure and property-performance relationship of the as-produced conjugated scaffolds.Herein,the mechanochemistry-driven construction of conjugated porous networks(CPNs),the carbon-based materials(e.g.,graphite and graphyne),and carbon supported single atom catalysts(CS-SACs)are discussed and summarized.The electrochemical performance of the afforded conductive scaffolds as electrode materials in supercapacitors and alkali-ion batteries is elucidated.Finally,the challenges and potential opportunities related to the construction of conjugated scaffolds driven by mechanochemistry are also discussed and concluded.
基金the National Science Fund for Distinguished Young Scholars(grant no.21925603)support of the National Natural Science Foundation of China(grant nos.22076187,11975152,11875057).The work of J.K.G.was supported by the U.S.Departme。
文摘Herein,we report the synthesis and structures of two novel mixed-metal clusters denoted as Th_(9)Ag_(6)and Th_(9)Ag_(12).Both clusters feature unprecedented Th_(9)cores.The cores are tricapped trigonal prism moieties that are novel among actinides.Attempted alternative synthesis routes indicate that the Th_(9)clusters are accessible only through slow introduction of Ag_(+)into a solution containing a Th6 cluster modified with 2-picolinic acid.Alternative rapid addition of Ag_(+)leads to dissociation of the Th6 cluster with formation of a high-purity(ThAg)_(∞)two-dimensional layered structure material.A mechanism for cluster dissociation and reassembly to yield Th_(9)from Th6 is proposed that is consistent with spectroscopic observations and computational results.Because of Ag⋯Ag andπ–πinteractions,the Th_(9)Ag_(12)cluster exhibits high stability in air,at elevated temperature,underγ-irradiation,and in common solvents.
基金The research was supported financially by the Division of Chemical Sciences,Geosciences,and Biosciences,Office of Basic Energy Sciences,US Department of Energy.
文摘Organic moieties-derived salts with permanent porosity and polarized channels have shown unique features and attractive performance in the field of adsorption,separation,and conduction.However,state-of-the-art organic salts generally rely on ionic interaction and hydrogen bonding formation to maintain the porous channels.The synthesis of organic moiety-derived saltswith permanent accessible pores even after removal of the trapped guest molecules,and without the constraint of hydrogen bonding formation still remains a great challenge.Herein,we present an expeditious construction pathway to generate hierarchically nanoporous barium salts without hydrogen bonding formation.The strong ionic interaction of the bariumcation and sulfonate anions led to rapid reaction equilibrium(∼2 min),affording diverse barium-derived ionic polymer(Ba-IP)with permanent porosity and highly polarized channels.The produced Ba-IP materials with abundant cations and anions displayed high CO_(2)/N2 and CO_(2)/CH_(4)separation performance,with the selectivities reaching up to 89.5 and 280,respectively,at 273 K,surpassingmost of the organic polymers functionalized by ionic moieties.
基金research at the Oak Ridge National Laboratory,managed by UT Battelle,LLC,for the U.S.Department of Energy(DOE)under Contract No.DE-AC05-00OR22725sponsored by the Laboratory Directed Research and Development Program at Oak Ridge National Laboratory.P.-F.C.acknowledges financial support by Fundamental Research Funds for the Central Universities(buctrc202222)。
文摘Dynamic polymers with both physical interactions and dynamic covalent bonds exhibit superior performance,but achieving such dry polymers in an effi-cient manner remains a challenge.Herein,we report a novel organic solvent quenched polymer synthesis using the natural molecule thioctic acid(TA),which has both a dynamic disulfide bond and carboxylic acid.The effects of the solvent type and concentration along with reaction times on the proposed reaction were thoroughly explored for polymer synthesis.Solid-state proton nuclear magnetic resonance(1 H NMR)and first-principles simulations were carried out to investigate the reaction mechanism.They show that the chlorinated solvent can efficiently stabilize and mediate the depolymerization of poly(TA),which is more kinetically favorable upon lowering the temperature.Attributed to the numerous dynamic covalent disulfide bonds and noncovalent hydrogen bonds,the obtained poly(TA)shows high extensibility,self-healing,and reprocessable properties.It can also be employed as an efficient adhesive even on a Teflon surface and 3D printed using the fused deposition modeling technique.This new polymer synthesis approach of using organic solvents as catalysts along with the unique reaction mechanism provides a new pathway for efficient polymer synthesis,especially for multifunctional dynamic polymers.
基金sponsored by the US Department of EnergyOffice of Nuclear Energy+2 种基金under contract DE-AC05-00OR22725 with Oak Ridge National Laboratorymanaged by UT-BattelleLLC
文摘Polymer-coated mesoporous carbon nanocomposites were prepared from the immobilization of acrylonitrile and acrylic acid copolymers with divinylbenzene as a crosslinker onto a mesoporous carbon framework.High surface areas were maintained after polymerization with accessible porosity.This functional nanocomposite was tested as an adsorbent for uranium from high salinity solutions.Uranium adsorption results have shown that the adsorption capacities are strongly influenced by the density of the amidoxime groups and the specific surface area.