Electrochemical energy storage becomes indispensable due to the wide-scale implementation of intermittent renewable energy and the growing market for portable electronic devices. Nowadays, lithium-ion batteries are pr...Electrochemical energy storage becomes indispensable due to the wide-scale implementation of intermittent renewable energy and the growing market for portable electronic devices. Nowadays, lithium-ion batteries are prevalent and mature.展开更多
Transplantation of probiotics to the intestine can positively regulate the gut microbiota,thereby promoting the immune system and treating various diseases.However,the harsh gastrointestinal environment and short rete...Transplantation of probiotics to the intestine can positively regulate the gut microbiota,thereby promoting the immune system and treating various diseases.However,the harsh gastrointestinal environment and short retention time in the gastrointestinal tract significantly limit the bioavailability and intestinal colonization of probiotics.Herein,we present a double-layer polysaccharide hydrogel(DPH)in the form of a double-layer structure composed of a carboxymethyl cellulose(CMCL)supramolecular inner layer and a dialdehyde alginate(DAA)cross-linked carboxymethyl chitosan(CMCS)outer layer.This doublelayer structure allows DPH to encapsulate and deliver probiotics in a targeted manner within the body.In the stomach,the cage structure of the DPH is closed,and the outer layer absorbs surrounding liquids to form a barrier to protect the probiotics from gastric fluids.In the intestine,the cage structure opens and disintegrates,releasing the probiotics.Thus,DPH endows probiotics with excellent intestine-targeted delivery,improved oral bioavailability,enhanced gastrointestinal tract tolerance,and robust mucoadhesion capacity.The encapsulated probiotics exhibit almost unchanged bioactivity in the gastrointestinal tract before release,as well as improved oral delivery.In particular,probiotics encapsulated by DPH exhibit 100.1 times higher bioavailability and 10.6 times higher mucoadhesion than free probiotics in an animal model 48 h post-treatment.In addition,with a remarkable ability to survive and be retained in the intestine,probiotics encapsulated by DPH show excellent in vitro and in vivo competition with pathogens.Notably,DAA-mediated dynamic crosslinking not only maintains the overall integrity of the hydrogels but also controls the release timing of the probiotics.Thus,it is expected that encapsulated substances(probiotics,proteins,etc.)can be delivered to specific sites of the intestinal tract by means of DPH,by controlling the dynamic covalent crosslinking.展开更多
An ancient hexaploidization event in the most but not all Asteraceae plants,may have been responsible for shaping the genomes of many horticultural,ornamental,and medicinal plants that promoting the prosperity of the ...An ancient hexaploidization event in the most but not all Asteraceae plants,may have been responsible for shaping the genomes of many horticultural,ornamental,and medicinal plants that promoting the prosperity of the largest angiosperm family on the earth.However,the duplication process of this hexaploidy,as well as the genomic and phenotypic diversity of extant Asteraceae plants caused by paleogenome reorganization,are still poorly understood.We analyzed 11 genomes from 10 genera in Asteraceae,and redated the Asteraceae common hexaploidization(ACH)event∼70.7–78.6 million years ago(Mya)and the Asteroideae specific tetraploidization(AST)event∼41.6–46.2 Mya.Moreover,we identified the genomic homologies generated from the ACH,AST and speciation events,and constructed a multiple genome alignment framework for Asteraceae.Subsequently,we revealed biased fractionations between the paleopolyploidization produced subgenomes,suggesting the ACH and AST both are allopolyplodization events.Interestingly,the paleochromosome reshuffling traces provided clear evidence for the two-step duplications of ACH event in Asteraceae.Furthermore,we reconstructed ancestral Asteraceae karyotype(AAK)that has 9 paleochromosomes,and revealed a highly flexible reshuffling of Asteraceae paleogenome.Of specific significance,we explored the genetic diversity of Heat Shock Transcription Factors(Hsfs)associated with recursive whole-genome polyploidizations,gene duplications,and paleogenome reshuffling,and revealed that the expansion of Hsfs gene families enable heat shock plasticity during the genome evolution of Asteraceae.Our study provides insights on polyploidy and paleogenome remodeling for the successful establishment of Asteraceae,and is helpful for further communication and exploration of the diversification of plant families and phenotypes.展开更多
Dielectric pulse capacitors are of great concerns due to the fast charge/discharge rate and high-power density over traditional counterparts.However,energy-storage capacitor in power converters typically works at a la...Dielectric pulse capacitors are of great concerns due to the fast charge/discharge rate and high-power density over traditional counterparts.However,energy-storage capacitor in power converters typically works at a large DC-biased voltage,where the energy-storge density(Wdis)and efficiency(h)will dramatically decay,thus fatally blocks its further applications.Herein,we proposed a synergistic strategy to achieve a comprehensively improved energy storage property in Bi1exNaxTiO_(3)-NaNbO_(3)based ceramics.Configuration of chemical composition optimization,A-site vacancy engineering,grain size refinement,and sample thickness reduction were designed in the ceramics.Finally,an optimum Wdis of 8.04 J/cm^(3)and an ultrahigh h of 85%was achieved for the 0.50(0.95Bi_(0.52)Na_(0.44)TiO_(3)-0.05SrZrO_(3))-0.50NaNbO_(3)composite under a breakdown strength of 630 kV/cm,along with a stable DC-biased capacitance retention.Additionally,a superior performance stability was affirmed in a wide temperature/frequency range(25-150℃and 1-100 Hz,respectively).It also exhibits an impressive ability in fatigue resistance after being subjected to up to 106 cycles,which enable it to be a suitable candidate for high energy density storage devices.展开更多
Inulin has been used as a prebiotic to alleviate glucose and lipid metabolism disorders in mice and humans by modulating the gut microbiota. However, the mechanism underlying the alleviation of metabolic disorders by ...Inulin has been used as a prebiotic to alleviate glucose and lipid metabolism disorders in mice and humans by modulating the gut microbiota. However, the mechanism underlying the alleviation of metabolic disorders by inulin through interactions between the gut microbiota and host cells is unclear. We use ob/ob mice as a model to study the effect of inulin on the cecal microbiota by16 S rRNA gene amplicon sequencing and its interaction with host cells by transcriptomics. The inulin-supplemented diet improved glucose and lipid metabolism disorder parameters in ob/ob mice,alleviating fat accumulation and glucose intolerance. The a diversity of gut microbial community of ob/ob mice was reduced after inulin treatment, while the b diversity tended to return to the level of wild type mice. Interestingly, Prevotellaceae UCG 001(family Prevotellaceae) was obviously enriched after inulin treatment. A comparative analysis of the gene expression profile showed that the cecal transcriptome was changed in leptin gene deficiency mice, whereas the inulin-supplemented diet partially reversed the changes in leptin gene-related signaling pathways, especially AMPK signaling pathway, where the levels of gene expression became comparable to those in wild type mice.Further analysis indicated that Prevotellaceae UCG 001 was positively correlated with the AMPK signaling pathway, which was negatively correlated with markers of glycolipid metabolism disorders. Our results suggest that the inulin-supplemented diet alleviates glucose and lipid metabolism disorders by partially restoring leptin related pathways mediated by gut microbiota.展开更多
The demanding all-in-one electrocatalyst system for oxygen reduction reaction(ORR),oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)in zinc-air batteries or water splitting requires elaborate material...The demanding all-in-one electrocatalyst system for oxygen reduction reaction(ORR),oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)in zinc-air batteries or water splitting requires elaborate material manufacturing,which is usually complicated and time-consuming.Efficient interface engineering between MXene and highly active electrocatalytic species(CoS_(2))is,herein,achieved by an in situ hydrothermal growth and facile sulfurization process.The CoS_(2)@MXene electrocatalyst is composed by one-dimensional CoS_(2)nanowires and two-dimensional MXene nanosheets,which lead to a hierarchical structure(large specific surface area and abundant active sites),a spatial electron redistribution(high intrinsic activity),and high anchoring strength(superior performance stability).Therefore,the electrocatalyst achieves enhanced catalytic activity and longtime stability for ORR(a half-wave potential of 0.80 V),OER(an overpotential of 270 mV at 10 mA cm^(-2),i.e.,η10=270 mV)and HER(η10=175 mV).Furthermore,the asymmetry water splitting system based on the CoS_(2)@MXene composites delivers a low overall voltage of 1.63 V at 10 mA cm^(-2).The solidstate zinc-air batteries using CoS_(2)@MXene as the air cathode display a small charge-discharge voltage gap(0.53 V at1 mA cm^(-2))and superior stability(60 circles and 20-h continuous test).The energy interconversion between the chemical energy and electricity can be achieved by a self-powered system via integrating the water splitting system and quasisolid-state zinc-air batteries.Supported by in situ Raman analyses,the formation of cobalt oxyhydroxide species provides the active sites for water oxidation.This study paves apromising avenue for the design and application of multifunctional nanocatalysts.展开更多
As a potential electrochemical energy storage device,zinc–air batteries(ZABs)received considerable interest in the feld of energy conversion and storage due to its high energy density and eco-friendliness.Nevertheles...As a potential electrochemical energy storage device,zinc–air batteries(ZABs)received considerable interest in the feld of energy conversion and storage due to its high energy density and eco-friendliness.Nevertheless,the sluggish kinetics of the oxygen reduction and oxygen evolution reactions limit the commercial development of ZABs,so it is of great signifcance to develop efcient,low-cost and non-noble metal bifunctional catalysts.Electrospun one-dimensional nanofbers with unique properties such as high porosity and large surface area have great advantages on possessing more active sites,shortening the difusion pathways for ions/electrons,and improving the kinetics via intercalation/de-intercalation processes,which endow them with promising application in the feld of energy storage devices,especially ZABs.This review frstly introduces the electrospinning technique.Then,the oxygen reduction/evolution reaction triggered by electrospun nanofbers with selfsupported structures are presented,followed by the application of electrospun nanofbers for liquid and fexible solid-state ZABs.Finally,the remaining challenges and research directions of ZABs based on electrospun nanofbers electrocatalysts are briefy discussed.展开更多
Electromagnetic waves carrying an orbital angular momentum (OAM) are of great interest. However, most OAM antennas presentdisadvantages such as a complicated structure, low efficiency, and large divergence angle, whic...Electromagnetic waves carrying an orbital angular momentum (OAM) are of great interest. However, most OAM antennas presentdisadvantages such as a complicated structure, low efficiency, and large divergence angle, which prevents their practicalapplications. So far, there are few papers and research focuses on the problem of the divergence angle. Herein, a metasurfaceantenna is proposed to obtain the OAM beams with a small divergence angle. The circular arrangement and phase gradient wereused to simplify the structure of the metasurface and obtain the small divergence angle, respectively. The proposed metasurfaceantenna presents a high transmission coefficient and effectively decreases the divergence angle of the OAM beam. All thetheoretical analyses and derivation calculations were validated by both simulations and experiments. This compact structurepaves the way to generate OAM beams with a small divergence angle.展开更多
With the increasing impacts of climate change and resource depletion,dielectric capacitors,with their exceptional stability,fast charging and discharging rates,and ability to operate under more extreme conditions,are ...With the increasing impacts of climate change and resource depletion,dielectric capacitors,with their exceptional stability,fast charging and discharging rates,and ability to operate under more extreme conditions,are emerging as promising high-demand candidates for high-performance energy storage devices,distinguishing them from traditional electrochemical capacitors and batteries.However,due to the shortcomings of various dielectric ceramics(e.g.,paraelectrics(PEs),ferroelectrics(FEs),and antiferroelectrics(AFEs)),their low polarizability,low breakdown strength(BDS),and large hysteresis loss limit their standalone use in the advancement of energy storage ceramics.Therefore,synthesizing novel perovskite-based materials that exhibit high energy density,high energy efficiency,and low loss is crucial for achieving superior energy storage performance.In this review,we outline the recent development of perovskitebased ferroelectric energy storage ceramics from the perspective of combinatorial optimization for tailoring ferroelectric hysteresis loops and comprehensively discuss the properties arising from the different combinations of components.We also provide future guidelines in this realm.Therefore,the combinatorial optimization strategy in this review will open up a practical route toward the application of new high-performance ferroelectric energy storage devices.展开更多
Electrochemical CO_(2)reduction(ECR)is one of the most effective methods to obtain carbonaceous chemicals and reduce greenhouse gases passingly under the ambient condition.However,efficient electrocatalysts featured w...Electrochemical CO_(2)reduction(ECR)is one of the most effective methods to obtain carbonaceous chemicals and reduce greenhouse gases passingly under the ambient condition.However,efficient electrocatalysts featured with high selectivity and stability are still lacking.A novel molecule-mediated Ag electrocatalyst with capped thiols is rationally designed for high-performance ECR.The thiol-capped and carbon-supported Ag nanostructures(Ag-TC)are formed by in situ electrochemical reduction from three-dimentional(3D)Ag-thiol metal-organic compound with cysteine as the anchor agent and carbon source.Ag-TC exhibits high selectivity and stability for CO_(2)conversion to CO(86.7%),which is more catalytically active than that of common Ag nanoparticles.The function of thiols for ECR is proved by replacing cysteine with alanine without thiol group.Meanwhile,alternatively replacing and removing the surface molecules on the Ag foil further demonstrate the effct of thiols.This work enlightens the promise of in situ construction method for molecule capped metal electrocatalyst towards selective and stable ECR.展开更多
The presence of bacteria directly affects wound healing.Chitosan-based hydrogel biomaterials are a solution as they offer advantages for wound-healing applications due to their strong antimicrobial properties.Here,a d...The presence of bacteria directly affects wound healing.Chitosan-based hydrogel biomaterials are a solution as they offer advantages for wound-healing applications due to their strong antimicrobial properties.Here,a double-cross-linking chitosanbased hydrogel with antibacterial,self-healing,and injectable properties is reported.Thiolated chitosan was successfully prepared,and the thiolated chitosan molecules were cross-linked by Ag-S coordination to form a supramolecular hydrogel.Subsequently,the amine groups in the thiolated chitosan covalently cross-linked with genipin to further promote hydrogel formation.In vitro experimental results indicate that hydrogel can release Ag^(+)over an extended time,achieving an antibacterial rate of over 99% against Escherichia coli and Staphylococcus aureus.Due to the reversible and dynamic feature of Ag-S coordination,an antibacterial hydrogel exhibited injectable and self-healing capabilities.Additionally,the hydrogel showed excellent biocompatibility and biodegradability.展开更多
Absorption-dominant electromagnetic interference(EMI)shielding materials are promising in reducing electromagnetic radiation pollution,but their preparation processes are usually difficult and unsuitable for large-sca...Absorption-dominant electromagnetic interference(EMI)shielding materials are promising in reducing electromagnetic radiation pollution,but their preparation processes are usually difficult and unsuitable for large-scale preparation.In this work,multiple folded Bi_(2)Se_(3)/PVDF nanocomposite films were fabri-cated by using a convenient tape-casting method and multiple folding,which can be easily extended in industrial applications.The EMI shielding effectiveness(SE)of the composite materials was investigated,which shows typical absorption-dominant behavior and can substantially reduce secondary reflections.Specifically,for the 35%(in volume)Bi_(2)Se_(3)/PVDF nanocomposite film,the SE_(A)of single-layered film with a thickness of 60 mm reaches 20 dB while SE_(R)is lower than 5 dB.After folding the film into eight layers,the SE_(A)increased to 50 dB while SE_(R)remains below 5 dB.This method provides an effective way to the fabrication of absorption-dominant electromagnetic absorption(EMA)and EMI shielding material.展开更多
Erratum to Nano Research 2022,15(4):3283−3289 https://doi.org/10.1007/s12274-021-3978-7 One funding number in the Acknowledgements section was unfortunately mistakenly used.This error did not affect any of the conclus...Erratum to Nano Research 2022,15(4):3283−3289 https://doi.org/10.1007/s12274-021-3978-7 One funding number in the Acknowledgements section was unfortunately mistakenly used.This error did not affect any of the conclusions from the published paper.展开更多
Trehalose is a widely used and safe natural disaccharide.Maltooligosyl trehalose hydrolase(MTHase)is one of the key enzymes for trehalose preparation by double enzyme method using starch or dextrin as substrate.In ind...Trehalose is a widely used and safe natural disaccharide.Maltooligosyl trehalose hydrolase(MTHase)is one of the key enzymes for trehalose preparation by double enzyme method using starch or dextrin as substrate.In industrial production,the thermalstability of MTHase is of great significance.We first heterogeneously expressed MTHase from Arthrobacter in E.coli strains BL21(DE3).Based on the overall stability of the protein after virtual saturation mutation predicted by FoldX and the evolutionary information from PSSM,15 mutations were selected and combined.Finally,the combinatorial mutant G589P/A57P was obtained.At 60℃,the t_(1/2)of G589P/A57P and wild type are 37 min and 19 min,respectively,which is 1.9 times higher than that of wild type.The enzyme kinetic parameters of G589P/A57P were analyzed.The K_(M)and k_(cat)are 4.82 mM and 1136 s^(−1),respectively,and the results were close to the wild type,indicating that the mutation did not reduce the catalytic efficiency of the enzyme.The molecular dynamics simulation results show that the rigidity and thermal stability of G589P/A57P protein increase in the range of residues 50-100 and 400-500,which may be due to the proline effect caused by the introduction of proline.展开更多
文摘Electrochemical energy storage becomes indispensable due to the wide-scale implementation of intermittent renewable energy and the growing market for portable electronic devices. Nowadays, lithium-ion batteries are prevalent and mature.
基金supported by the National Natural Science Foundation of China (U21A20271)the China Agriculture Research System of the MOF and MARA (CARS-48)+2 种基金the Natural Science Foundation of Shandong Province (ZR2020JQ15)the Taishan Scholar Project of Shandong Province (tsqn201812020)the Fundamental Research Funds for the Central Universities (201941002).
文摘Transplantation of probiotics to the intestine can positively regulate the gut microbiota,thereby promoting the immune system and treating various diseases.However,the harsh gastrointestinal environment and short retention time in the gastrointestinal tract significantly limit the bioavailability and intestinal colonization of probiotics.Herein,we present a double-layer polysaccharide hydrogel(DPH)in the form of a double-layer structure composed of a carboxymethyl cellulose(CMCL)supramolecular inner layer and a dialdehyde alginate(DAA)cross-linked carboxymethyl chitosan(CMCS)outer layer.This doublelayer structure allows DPH to encapsulate and deliver probiotics in a targeted manner within the body.In the stomach,the cage structure of the DPH is closed,and the outer layer absorbs surrounding liquids to form a barrier to protect the probiotics from gastric fluids.In the intestine,the cage structure opens and disintegrates,releasing the probiotics.Thus,DPH endows probiotics with excellent intestine-targeted delivery,improved oral bioavailability,enhanced gastrointestinal tract tolerance,and robust mucoadhesion capacity.The encapsulated probiotics exhibit almost unchanged bioactivity in the gastrointestinal tract before release,as well as improved oral delivery.In particular,probiotics encapsulated by DPH exhibit 100.1 times higher bioavailability and 10.6 times higher mucoadhesion than free probiotics in an animal model 48 h post-treatment.In addition,with a remarkable ability to survive and be retained in the intestine,probiotics encapsulated by DPH show excellent in vitro and in vivo competition with pathogens.Notably,DAA-mediated dynamic crosslinking not only maintains the overall integrity of the hydrogels but also controls the release timing of the probiotics.Thus,it is expected that encapsulated substances(probiotics,proteins,etc.)can be delivered to specific sites of the intestinal tract by means of DPH,by controlling the dynamic covalent crosslinking.
基金This work was funded by the National Natural Science Foundation of China(32170236 and 31501333 to J.P.W.)the Hebei Natural Science Foundation(C2020209064 to J.P.W.)the Fundamental Research for the Hebei Province Universities(JQN2020018 to T.L.).
文摘An ancient hexaploidization event in the most but not all Asteraceae plants,may have been responsible for shaping the genomes of many horticultural,ornamental,and medicinal plants that promoting the prosperity of the largest angiosperm family on the earth.However,the duplication process of this hexaploidy,as well as the genomic and phenotypic diversity of extant Asteraceae plants caused by paleogenome reorganization,are still poorly understood.We analyzed 11 genomes from 10 genera in Asteraceae,and redated the Asteraceae common hexaploidization(ACH)event∼70.7–78.6 million years ago(Mya)and the Asteroideae specific tetraploidization(AST)event∼41.6–46.2 Mya.Moreover,we identified the genomic homologies generated from the ACH,AST and speciation events,and constructed a multiple genome alignment framework for Asteraceae.Subsequently,we revealed biased fractionations between the paleopolyploidization produced subgenomes,suggesting the ACH and AST both are allopolyplodization events.Interestingly,the paleochromosome reshuffling traces provided clear evidence for the two-step duplications of ACH event in Asteraceae.Furthermore,we reconstructed ancestral Asteraceae karyotype(AAK)that has 9 paleochromosomes,and revealed a highly flexible reshuffling of Asteraceae paleogenome.Of specific significance,we explored the genetic diversity of Heat Shock Transcription Factors(Hsfs)associated with recursive whole-genome polyploidizations,gene duplications,and paleogenome reshuffling,and revealed that the expansion of Hsfs gene families enable heat shock plasticity during the genome evolution of Asteraceae.Our study provides insights on polyploidy and paleogenome remodeling for the successful establishment of Asteraceae,and is helpful for further communication and exploration of the diversification of plant families and phenotypes.
基金the National Natural Science Foundation of China(No.52372101,52032005)。
文摘Dielectric pulse capacitors are of great concerns due to the fast charge/discharge rate and high-power density over traditional counterparts.However,energy-storage capacitor in power converters typically works at a large DC-biased voltage,where the energy-storge density(Wdis)and efficiency(h)will dramatically decay,thus fatally blocks its further applications.Herein,we proposed a synergistic strategy to achieve a comprehensively improved energy storage property in Bi1exNaxTiO_(3)-NaNbO_(3)based ceramics.Configuration of chemical composition optimization,A-site vacancy engineering,grain size refinement,and sample thickness reduction were designed in the ceramics.Finally,an optimum Wdis of 8.04 J/cm^(3)and an ultrahigh h of 85%was achieved for the 0.50(0.95Bi_(0.52)Na_(0.44)TiO_(3)-0.05SrZrO_(3))-0.50NaNbO_(3)composite under a breakdown strength of 630 kV/cm,along with a stable DC-biased capacitance retention.Additionally,a superior performance stability was affirmed in a wide temperature/frequency range(25-150℃and 1-100 Hz,respectively).It also exhibits an impressive ability in fatigue resistance after being subjected to up to 106 cycles,which enable it to be a suitable candidate for high energy density storage devices.
基金supported by the National Basic Research Program of China (Grant No. 2015CB554200)the Key Research Program of the Chinese Academy of Sciences (Grant No. KFZD-SW-219)the National Natural Science Foundation of China (Grant Nos. 31601081 and 31471203)
文摘Inulin has been used as a prebiotic to alleviate glucose and lipid metabolism disorders in mice and humans by modulating the gut microbiota. However, the mechanism underlying the alleviation of metabolic disorders by inulin through interactions between the gut microbiota and host cells is unclear. We use ob/ob mice as a model to study the effect of inulin on the cecal microbiota by16 S rRNA gene amplicon sequencing and its interaction with host cells by transcriptomics. The inulin-supplemented diet improved glucose and lipid metabolism disorder parameters in ob/ob mice,alleviating fat accumulation and glucose intolerance. The a diversity of gut microbial community of ob/ob mice was reduced after inulin treatment, while the b diversity tended to return to the level of wild type mice. Interestingly, Prevotellaceae UCG 001(family Prevotellaceae) was obviously enriched after inulin treatment. A comparative analysis of the gene expression profile showed that the cecal transcriptome was changed in leptin gene deficiency mice, whereas the inulin-supplemented diet partially reversed the changes in leptin gene-related signaling pathways, especially AMPK signaling pathway, where the levels of gene expression became comparable to those in wild type mice.Further analysis indicated that Prevotellaceae UCG 001 was positively correlated with the AMPK signaling pathway, which was negatively correlated with markers of glycolipid metabolism disorders. Our results suggest that the inulin-supplemented diet alleviates glucose and lipid metabolism disorders by partially restoring leptin related pathways mediated by gut microbiota.
基金supported by the National Natural Science Foundation of China(51871119 and 51901100)the High-Level Entrepreneurial and Innovative Talents Program of Jiangsu Province,Jiangsu Provincial Funds for Natural Science Foundation(BK20170793 and BK20180015)+2 种基金the Six Talent Peak Project of Jiangsu Province(2018-XCL-033)China Postdoctoral Science Foundation(2018M640481 and 2019T120426)the Foundation of Graduation Innovation Center in NUAA(kfjj20190609)。
文摘The demanding all-in-one electrocatalyst system for oxygen reduction reaction(ORR),oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)in zinc-air batteries or water splitting requires elaborate material manufacturing,which is usually complicated and time-consuming.Efficient interface engineering between MXene and highly active electrocatalytic species(CoS_(2))is,herein,achieved by an in situ hydrothermal growth and facile sulfurization process.The CoS_(2)@MXene electrocatalyst is composed by one-dimensional CoS_(2)nanowires and two-dimensional MXene nanosheets,which lead to a hierarchical structure(large specific surface area and abundant active sites),a spatial electron redistribution(high intrinsic activity),and high anchoring strength(superior performance stability).Therefore,the electrocatalyst achieves enhanced catalytic activity and longtime stability for ORR(a half-wave potential of 0.80 V),OER(an overpotential of 270 mV at 10 mA cm^(-2),i.e.,η10=270 mV)and HER(η10=175 mV).Furthermore,the asymmetry water splitting system based on the CoS_(2)@MXene composites delivers a low overall voltage of 1.63 V at 10 mA cm^(-2).The solidstate zinc-air batteries using CoS_(2)@MXene as the air cathode display a small charge-discharge voltage gap(0.53 V at1 mA cm^(-2))and superior stability(60 circles and 20-h continuous test).The energy interconversion between the chemical energy and electricity can be achieved by a self-powered system via integrating the water splitting system and quasisolid-state zinc-air batteries.Supported by in situ Raman analyses,the formation of cobalt oxyhydroxide species provides the active sites for water oxidation.This study paves apromising avenue for the design and application of multifunctional nanocatalysts.
基金This work was supported by the National Natural Science Foundation of China(51871119,51901100,and 22101132)Jiangsu Provincial Founds for Natural Science Foundation(BK20170793,BK20180015,and BK20210311)State Key Laboratory for Modifcation of Chemical Fibers and Polymer Materials,Donghua University.
文摘As a potential electrochemical energy storage device,zinc–air batteries(ZABs)received considerable interest in the feld of energy conversion and storage due to its high energy density and eco-friendliness.Nevertheless,the sluggish kinetics of the oxygen reduction and oxygen evolution reactions limit the commercial development of ZABs,so it is of great signifcance to develop efcient,low-cost and non-noble metal bifunctional catalysts.Electrospun one-dimensional nanofbers with unique properties such as high porosity and large surface area have great advantages on possessing more active sites,shortening the difusion pathways for ions/electrons,and improving the kinetics via intercalation/de-intercalation processes,which endow them with promising application in the feld of energy storage devices,especially ZABs.This review frstly introduces the electrospinning technique.Then,the oxygen reduction/evolution reaction triggered by electrospun nanofbers with selfsupported structures are presented,followed by the application of electrospun nanofbers for liquid and fexible solid-state ZABs.Finally,the remaining challenges and research directions of ZABs based on electrospun nanofbers electrocatalysts are briefy discussed.
基金The authors acknowledge the support of the National Natural Science Foundation of China(Grant Nos.61774020,51788104,51802023,61690195,61605015,61575028,51532004,and 51802021)the Science and Technology Plan of Shenzhen City(Grant No.JCYJ20180306173235924)the Ph.D.Student’s Short-Term Overseas Study and Exchange Program of BUPT.
文摘Electromagnetic waves carrying an orbital angular momentum (OAM) are of great interest. However, most OAM antennas presentdisadvantages such as a complicated structure, low efficiency, and large divergence angle, which prevents their practicalapplications. So far, there are few papers and research focuses on the problem of the divergence angle. Herein, a metasurfaceantenna is proposed to obtain the OAM beams with a small divergence angle. The circular arrangement and phase gradient wereused to simplify the structure of the metasurface and obtain the small divergence angle, respectively. The proposed metasurfaceantenna presents a high transmission coefficient and effectively decreases the divergence angle of the OAM beam. All thetheoretical analyses and derivation calculations were validated by both simulations and experiments. This compact structurepaves the way to generate OAM beams with a small divergence angle.
基金support from the National Natural Science Foundation of China(No.52202154)support from the Highperformance Computing Platform of China Agricultural University.
文摘With the increasing impacts of climate change and resource depletion,dielectric capacitors,with their exceptional stability,fast charging and discharging rates,and ability to operate under more extreme conditions,are emerging as promising high-demand candidates for high-performance energy storage devices,distinguishing them from traditional electrochemical capacitors and batteries.However,due to the shortcomings of various dielectric ceramics(e.g.,paraelectrics(PEs),ferroelectrics(FEs),and antiferroelectrics(AFEs)),their low polarizability,low breakdown strength(BDS),and large hysteresis loss limit their standalone use in the advancement of energy storage ceramics.Therefore,synthesizing novel perovskite-based materials that exhibit high energy density,high energy efficiency,and low loss is crucial for achieving superior energy storage performance.In this review,we outline the recent development of perovskitebased ferroelectric energy storage ceramics from the perspective of combinatorial optimization for tailoring ferroelectric hysteresis loops and comprehensively discuss the properties arising from the different combinations of components.We also provide future guidelines in this realm.Therefore,the combinatorial optimization strategy in this review will open up a practical route toward the application of new high-performance ferroelectric energy storage devices.
基金This work was supported by the National Natural Science Foundation of China(No.2210011636)the Natural Science Foundation of Jiangsu Province(No.BK20210311)+3 种基金China Postdoctoral Science Foundation(Nos.2021M691561 and 2021T140319)Jiangsu Planned Projects for Postdoctoral Research Funds(No.2021K547C)CAS Key Laboratory of Nano-Bio Interface(No.21NBI02)the Fundamental Research Funds for the Central Universities(No.NS2021037).
文摘Electrochemical CO_(2)reduction(ECR)is one of the most effective methods to obtain carbonaceous chemicals and reduce greenhouse gases passingly under the ambient condition.However,efficient electrocatalysts featured with high selectivity and stability are still lacking.A novel molecule-mediated Ag electrocatalyst with capped thiols is rationally designed for high-performance ECR.The thiol-capped and carbon-supported Ag nanostructures(Ag-TC)are formed by in situ electrochemical reduction from three-dimentional(3D)Ag-thiol metal-organic compound with cysteine as the anchor agent and carbon source.Ag-TC exhibits high selectivity and stability for CO_(2)conversion to CO(86.7%),which is more catalytically active than that of common Ag nanoparticles.The function of thiols for ECR is proved by replacing cysteine with alanine without thiol group.Meanwhile,alternatively replacing and removing the surface molecules on the Ag foil further demonstrate the effct of thiols.This work enlightens the promise of in situ construction method for molecule capped metal electrocatalyst towards selective and stable ECR.
基金supported by the National Key R&D Program of China(2020YFD0900205)the China Agriculture Research System(CARS-48).
文摘The presence of bacteria directly affects wound healing.Chitosan-based hydrogel biomaterials are a solution as they offer advantages for wound-healing applications due to their strong antimicrobial properties.Here,a double-cross-linking chitosanbased hydrogel with antibacterial,self-healing,and injectable properties is reported.Thiolated chitosan was successfully prepared,and the thiolated chitosan molecules were cross-linked by Ag-S coordination to form a supramolecular hydrogel.Subsequently,the amine groups in the thiolated chitosan covalently cross-linked with genipin to further promote hydrogel formation.In vitro experimental results indicate that hydrogel can release Ag^(+)over an extended time,achieving an antibacterial rate of over 99% against Escherichia coli and Staphylococcus aureus.Due to the reversible and dynamic feature of Ag-S coordination,an antibacterial hydrogel exhibited injectable and self-healing capabilities.Additionally,the hydrogel showed excellent biocompatibility and biodegradability.
基金supported by the National Natural Science Foundation of China(Grant No.51972032)BUPT Excellent Ph.D.Students Foundation(CX2021128).
文摘Absorption-dominant electromagnetic interference(EMI)shielding materials are promising in reducing electromagnetic radiation pollution,but their preparation processes are usually difficult and unsuitable for large-scale preparation.In this work,multiple folded Bi_(2)Se_(3)/PVDF nanocomposite films were fabri-cated by using a convenient tape-casting method and multiple folding,which can be easily extended in industrial applications.The EMI shielding effectiveness(SE)of the composite materials was investigated,which shows typical absorption-dominant behavior and can substantially reduce secondary reflections.Specifically,for the 35%(in volume)Bi_(2)Se_(3)/PVDF nanocomposite film,the SE_(A)of single-layered film with a thickness of 60 mm reaches 20 dB while SE_(R)is lower than 5 dB.After folding the film into eight layers,the SE_(A)increased to 50 dB while SE_(R)remains below 5 dB.This method provides an effective way to the fabrication of absorption-dominant electromagnetic absorption(EMA)and EMI shielding material.
基金the National Natural Science Foundation of China(No.2210011636)the Natural Science Foundation of Jiangsu Province(No.BK20210311)+3 种基金China Postdoctoral Science Foundation(Nos.2021M691561 and 2021T140319)Jiangsu Planned Projects for Postdoctoral Research Funds(No.2021K547C)CAS Key Laboratory of Nano-Bio Interface(No.21NBI02)the Fundamental Research Funds for the Central Universities(No.NS2021037).
文摘Erratum to Nano Research 2022,15(4):3283−3289 https://doi.org/10.1007/s12274-021-3978-7 One funding number in the Acknowledgements section was unfortunately mistakenly used.This error did not affect any of the conclusions from the published paper.
基金supported by the National Natural Science Foundation of China(No.32171471)Key Research and Development Project of Shandong Province,China(2019JZZY020605)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,Top-notch Academic Programs Project of Jiangsu Higher Education Institutions.
文摘Trehalose is a widely used and safe natural disaccharide.Maltooligosyl trehalose hydrolase(MTHase)is one of the key enzymes for trehalose preparation by double enzyme method using starch or dextrin as substrate.In industrial production,the thermalstability of MTHase is of great significance.We first heterogeneously expressed MTHase from Arthrobacter in E.coli strains BL21(DE3).Based on the overall stability of the protein after virtual saturation mutation predicted by FoldX and the evolutionary information from PSSM,15 mutations were selected and combined.Finally,the combinatorial mutant G589P/A57P was obtained.At 60℃,the t_(1/2)of G589P/A57P and wild type are 37 min and 19 min,respectively,which is 1.9 times higher than that of wild type.The enzyme kinetic parameters of G589P/A57P were analyzed.The K_(M)and k_(cat)are 4.82 mM and 1136 s^(−1),respectively,and the results were close to the wild type,indicating that the mutation did not reduce the catalytic efficiency of the enzyme.The molecular dynamics simulation results show that the rigidity and thermal stability of G589P/A57P protein increase in the range of residues 50-100 and 400-500,which may be due to the proline effect caused by the introduction of proline.
