Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution reaction.Traditional metal exsolution processes on...Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution reaction.Traditional metal exsolution processes on perovskites are often achieved by using the reducing hydrogen gas;however,this is not effective for the relatively stable phase,such as Ruddlesden-Popper perovskite oxides.To address this issue,triphenylphosphine is proposed to be a reduction promotor for accelerating the reduction and migration of the target metal atoms,aiming to achieve the effective exsolution of metallic species from Ruddlesden-Popper-type parent perovskites.Upon oxygen evolution reaction,these exsolved metallic aggregates are reconstructed into oxyhydroxides as the real active centers.After further modification by lowpercentage iridium oxide nanoclusters,the optimal catalyst delivered an overpotential as low as 305 mV for generating the density of 10 mA cm^(-2),outperforming these reported noble metal-containing perovskite-based alkaline oxygen evolution reaction electrocatalysts.This work provides a potential approach to activate catalytically inert oxides through promoting surface metal exsolution and explores a novel class of Ruddlesden-Poppertype oxides for electrocatalytic applications.展开更多
In conventional isochronous mass spectrometry(IMS)performed on a storage ring,the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times(T)of stored ions.Ho...In conventional isochronous mass spectrometry(IMS)performed on a storage ring,the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times(T)of stored ions.However,the resolution of T inevitably deteriorates due to the magnetic rigidity spread of the ions,limiting the mass-resolving power.In this study,we used the betatron tunes Q(the number of betatron oscillations per revolution)of the ions and established a correlation between T and Q.From this correlation,T was transformed to correspond to a fixed Q with higher resolution.Using these transformed T values,the masses of ^(63)Ge,^(65)As,^(67)Se,and ^(71)Kr agreed well with the mass values measured using the newly developed IMS(Bρ-IMS).We also studied the systematics of Coulomb displacement energies(CDEs)and found that anomalous staggering in CDEs was eliminated using new mass values.This method of T transformation is highly effective for conventional IMS equipped with a single time-of-flight detector.展开更多
To characterize the patterns of ABR waves in tree shrews, we must understand the hearing sensitivity and auditory function of healthy adult tree shrews. Fifteen tree shrews(30 ears) were stimulated with clicks and ton...To characterize the patterns of ABR waves in tree shrews, we must understand the hearing sensitivity and auditory function of healthy adult tree shrews. Fifteen tree shrews(30 ears) were stimulated with clicks and tone-pips at 11 different frequencies from 1 to 60 kHz. The ABR waves were recorded and analyzed. The ABR consisted of five to seven positive waves in the first 10 ms after a click stimulus, and the average hearing threshold of component III was 27.86 ± 3.78 dB SPL. Wave III was the largest and most clear. The ABR threshold was related to the tone-pip sitmulus by a "U" shaped curve. The sensitive frequency was approximately 8 kHz in tree shrews. The latencies systematically decreased with increasing stimulus frequencies. The ABR amplitudes of wave III increased as the sound pressure level increased. All of these results provide an empirical basis for future studies of hearing diseases in tree shrews.展开更多
Oxygen vacancies(Vo)in electrocatalysts are closely correlated with the hydrogen evo-lution reaction(HER)activity.The role of vacancy defects and the effect of their concentration,how-ever,yet remains unclear.Herein,B...Oxygen vacancies(Vo)in electrocatalysts are closely correlated with the hydrogen evo-lution reaction(HER)activity.The role of vacancy defects and the effect of their concentration,how-ever,yet remains unclear.Herein,Bi2O3,an unfavorable electrocata-lyst for the HER due to a less than ideal hydrogen adsorption Gibbs free energy(ΔGH*),is utilized as a perfect model to explore the func-tion of Vo on HER performance.Through a facile plasma irradia-tion strategy,Bi2O3 nanosheets with different Vo concentrations are fabricated to evaluate the influence of defects on the HER process.Unexpectedly,while the generated oxygen vacancies contribute to the enhanced HER performance,higher Vo concentrations beyond a saturation value result in a significant drop in HER activity.By tunning the Vo concentration in the Bi_(2)O_(3)nanosheets via adjusting the treatment time,the Bi2O3 catalyst with an optimized oxygen vacancy concentration and detectable charge carrier concentration of 1.52×10^(24)cm^(−3)demonstrates enhanced HER performance with an overpotential of 174.2 mV to reach 10 mA cm^(−2),a Tafel slope of 80 mV dec−1,and an exchange current density of 316 mA cm−2 in an alkaline solution,which approaches the top-tier activity among Bi-based HER electrocatalysts.Density-functional theory calculations confirm the preferred adsorption of H*onto Bi2O3 as a function of oxygen chemical potential(ΔμO)and oxygen partial potential(PO2)and reveal that high Vo concentrations result in excessive stability of adsorbed hydrogen and hence the inferior HER activity.This study reveals the oxygen vacancy concentration-HER catalytic activity relationship and provides insights into activating catalytically inert materials into highly efficient electrocatalysts.展开更多
Isochronous mass spectrometry(IMS)of heavyion storage rings is a powerful tool for the mass measurements of short-lived nuclei.In IMS experiments,masses are determined through precision measurements of the revolution ...Isochronous mass spectrometry(IMS)of heavyion storage rings is a powerful tool for the mass measurements of short-lived nuclei.In IMS experiments,masses are determined through precision measurements of the revolution times of the ions stored in the ring.However,the revolution times cannot be resolved for particles with nearly the same mass-to-charge(m/q)ratios.To overcome this limitation and to extract the accurate revolution times for such pairs of ion species with very close m/q ratios,in our early work on particle identification,we analyzed the amplitudes of the timing signals from the detector based on the emission of secondary electrons.Here,the previous data analysis method is further improved by considering the signal amplitudes,detection efficiencies,and number of stored ions in the ring.A sensitive Z-dependent parameter is introduced in the data analysis,leading to a better resolution of ^(34)Ar^(18+) and ^(51)Co^(27+) with A/Z=17/9.The mean revolution times of ^(34)Ar^(18+) and ^(51)Co^(27+) are deduced,although their time difference is merely 1.8 ps.The uncorrected,overlapped peak of these ions has a full width at half maximum of 7.7 ps.The mass excess of ^(51)Co was determined to be-27;332e41T keV,which is in agreement with the previous value of-27;342e48T keV.展开更多
Two-dimensional/two-dimensional(2D/2D)heterostructures consisting of two or more 2D building blocks possess intriguing electronic features at the nanosized interfacial regions,endowing the possibility for effectively ...Two-dimensional/two-dimensional(2D/2D)heterostructures consisting of two or more 2D building blocks possess intriguing electronic features at the nanosized interfacial regions,endowing the possibility for effectively modulating the confinement,and transport of charge carriers,excitons,photons,phonons,etc.to bring about a wide range of extraordinary physical,chemical,thermal,and/or mechanical properties.By rational design and synthesis of 2D/2D heterostructures,electrochemical properties for advanced batteries and electrocatalysis can be well regulated to meet some practical requirements.In this review,a summary on the commonly employed synthetic strategies for 2D/2D heterostructures is first given,followed by a comprehensive review on recent progress for their applications in batteries and various electrocatalysis reactions.Finally,a critical outlook on the current challenges and promising solutions is presented,which is expected to offer some insightful ideas on the design principles of advanced 2D-based nanomaterials to address the current challenges in sustainable energy storages and green fuel generations.展开更多
Two-dimensional（2D） metal oxide nanosheets have attracted much attention as potential electrode materials for rechargeable batteries in recent years. This is primarily due to their natural abundance, environmental c...Two-dimensional（2D） metal oxide nanosheets have attracted much attention as potential electrode materials for rechargeable batteries in recent years. This is primarily due to their natural abundance, environmental compatibility, and low cost as well as good electrochemical properties. Despite the fact that most metal oxides possess low conductivity, the introduction of some conductive heterogeneous components, such as nano-carbon, carbon nanotubes（CNTs）, and graphene, to form metal oxide-based hybrids,can effectively overcome this drawback. In this mini review, we will summarize the recent advances of three typical 2D metal oxide nanomaterials, namely, binary metal oxides, ternary metal oxides, and hybrid metal oxides, which are used for the electrochemical applications of next-generation rechargeable batteries, mainly for lithium-ion batteries（LIBs） and sodium-ion batteries（SIBs）. Hence, this review intends to functionalize as a good reference for the further research on 2D nanomaterials and the further development of energy-storage devices.展开更多
Electrochemical reduction of CO_(2)into high-value hydrocarbons and alcohols by using Cu-based catalysts is a promising and attractive technology for CO_(2)capture and utilization,resulting from their high catalytic a...Electrochemical reduction of CO_(2)into high-value hydrocarbons and alcohols by using Cu-based catalysts is a promising and attractive technology for CO_(2)capture and utilization,resulting from their high catalytic activity and selectivity.The mobility and accessibility of active sites in Cubased catalysts significantly hinder the development of efficient Cu-based catalysts for CO_(2)electrochemical reduction reaction(CO_(2)RR).Herein,a facile and effective strategy is developed to engineer accessible and structural stable Cu sites by incorporating single atomic Cu into the nitrogen cavities of the host graphitic carbon nitride(g-C_(3)N_(4))as the active sites for CO_(2)-to-CH_(4)conversion in CO_(2)RR.By regulating the coordination and density of Cu sites in g-C_(3)N_(4),an optimal catalyst corresponding to a one Cu atom in one nitrogen cavity reaches the highest CH_(4)Faraday efficiency of 49.04%and produces the products with a high CH_(4)/C_(2)H_(4)ratio over 9.This work provides the first experimental study on g-C_(3)N_(4)-supported single Cu atom catalyst for efficient CH_(4)production from CO_(2)RR and suggests a principle in designing highly stable and selective high-efficiency Cu-based catalysts for CO_(2)RR by engineering Cu active sites in 2D materials with porous crystal structures.展开更多
Poplar is an important afforestation and urban greening species.Poplar leaf development occurs in stages,from young to mature and then from mature to senescent;these are accompanied by various phenotypic and physiolog...Poplar is an important afforestation and urban greening species.Poplar leaf development occurs in stages,from young to mature and then from mature to senescent;these are accompanied by various phenotypic and physiological changes.However,the associated transcriptional regulatory network is relatively unexplored.We first used principal component analysis to classify poplar leaves at different leaf positions into two stages:developmental maturity(the stage of maximum photosynthetic capacity);and the stage when photosynthetic capacity started to decline and gradually changed to senescence.The two stages were then further subdivided into five intervals by gene expression clustering analysis:young leaves,the period of cell genesis and functional differentiation(L1);young leaves,the period of development and initial formation of photosynthetic capacity(L3-L7);the period of maximum photosynthetic capacity of functional leaves(L9-L13);the period of decreasing photosynthetic capacity of functional leaves(L15-L27);and the period of senescent leaves(L29).Using a weighted co-expression gene network analysis of regulatory genes,high-resolution spatiotemporal transcriptional regulatory networks were constructed to reveal the core regulators that regulate leaf development.Spatiotemporal transcriptome data of poplar leaves revealed dynamic changes in genes and miRNAs during leaf development and identified several core regulators of leaf development,such as GRF5 and MYB5.This in-depth analysis of transcriptional regulation during leaf development provides a theoretical basis for exploring the biological basis of the transcriptional regulation of leaf development and the molecular design of breeding for delaying leaf senescence.展开更多
Based on the idea of infinitesimal analysis, we establish the basic model of relation between speed and flow. Since putting a certain amount of self-driving car will affect the average speed of mixed traffic flow, we ...Based on the idea of infinitesimal analysis, we establish the basic model of relation between speed and flow. Since putting a certain amount of self-driving car will affect the average speed of mixed traffic flow, we choose the proportion of self-driving car to be a variable, denoted by k. Based on the least square method, we find two critical values of k that are 38.63% and 68.26%. When k 38.63%, the self-driving cars have a negative influence to the traffic. When 38.63% < k < 68.26%, they have a positive influence to the traffic. When k > 68.26%, they have significant improvement to the traffic capacity of the road.展开更多
Based on the entropy weight method and the gray relational analysis method, we first calculate the weight of each index and the correlation coefficient between the indicators, get the urban intelligent growth index, a...Based on the entropy weight method and the gray relational analysis method, we first calculate the weight of each index and the correlation coefficient between the indicators, get the urban intelligent growth index, and then calculate the annual growth rate of the composite index. We find the following results. First, Suzhou to improve its environment, the success rate of 109.67%. Saint Louis to improve its economy, the growth rate of 57.4%. Second, the sensitivity of the data analysis, each of the indicators is increased by 10%, 20%, 30%, other indicators remain unchanged. Recalculate the city’s intelligent growth index, we find that the greater the volatility, the greater the potential. The total population of the city, built green area, the total length of the bus operating a greater potential, built-up area, the smallest regional GDP potential. Finally, we propose an improved model combining remote sensing with GIS to analyze urban expansion and farmland loss from time and space qualitatively and quantitatively.展开更多
Two-dimensional (2D) heterostructures have shown great potential in advanced photovoltaics due to their restrained carrier recombination, prolonged exciton lifetime and improved light absorption. Herein, a 2D polarize...Two-dimensional (2D) heterostructures have shown great potential in advanced photovoltaics due to their restrained carrier recombination, prolonged exciton lifetime and improved light absorption. Herein, a 2D polarized heterostructure is constructed between Janus MoSSe and MoTe_(2) monolayers and is systematically investigated via first-principles calculations. Electronically, the valence band and conduction band of the MoSSe−MoTe_(2) (MoSeS−MoTe_(2)) are contributed by MoTe_(2) and MoSSe layers, respectively, and its bandgap is 0.71 (0.03) eV. A built-in electric field pointing from MoTe_(2) to MoSSe layers appears at the interface of heterostructures due to the interlayer carrier redistribution. Notably, the band alignment and built-in electric field make it a direct z-scheme heterostructure, benefiting the separation of photogenerated electron-hole pairs. Besides, the electronic structure and interlayer carrier reconstruction can be readily controlled by reversing the electric polarization of the MoSSe layer. Furthermore, the light absorption of the MoSSe/MoTe_(2) heterostructure is also improved in comparison with the separated monolayers. Consequently, in this work, a new z-scheme polarized heterostructure with polarization-controllable optoelectronic properties is designed for highly efficient optoelectronics.展开更多
Active metal-based batteries are drawing increased attention because of their inherent high energy density and specific capacity.Some grand challenges,such as dendrite growth,electrode degradation,rapid performance fa...Active metal-based batteries are drawing increased attention because of their inherent high energy density and specific capacity.Some grand challenges,such as dendrite growth,electrode degradation,rapid performance fading,etc.,have limited their practical application.Bioinspiration,which involves taking cues from the structures and functions of the natural world,can lead to a wealth of conceptually fresh approaches to regulator the metal ion transportation to achieve a dendrite-free metal plating,thwart the side-reaction reactions,and retard the structural distortions,for a more reliable and secure operation of active metal-based batteries.In this review,we concentrate on the fabrication and application of bioinspired designs in active metal-based batteries with enhanced performance,along with discussion on the challenges and opportunities associated with this promising topic.We anticipate that this review can offer some insights into the development of functional materials by learning from nature and provide some approaches for the innovations of either the battery structures or the energy materials for metal-based batteries.展开更多
Porous carbons(PCs)are one of the promising electrode materials for supercapacitors attributed to their low cost,superior electronic conductivity,easy availability,and tailored pore structures.Template methods have be...Porous carbons(PCs)are one of the promising electrode materials for supercapacitors attributed to their low cost,superior electronic conductivity,easy availability,and tailored pore structures.Template methods have been explored as the effective strategies for the fabrication of PCs with desirable morphology and highly controllable pore size distribution.Herein,this review firstly focuses on design and synthetic mechanism of various PCs via hard templates,soft templates,and dual-templates.Secondly,an overview of PCs is presented with a detailed discussion of the structure-activity relationship between electrochemical performances and pore structures.Thirdly,the current challenges and prospects of template-assisted synthesis of PCs for supercapacitors are highlighted regarding further researches.展开更多
There has been exponential growth in research activities on nanomaterials and nanotechnology for appli- cations in emerging technologies and sustainable energy in the past decade. The properties of nanomaterials have ...There has been exponential growth in research activities on nanomaterials and nanotechnology for appli- cations in emerging technologies and sustainable energy in the past decade. The properties of nanomaterials have been found to vary in terms of their shapes, sizes, and number of nanoscale dimensions, which have also further boosted the performance of nanomaterial-based electronic, catalytic, and sustainable energy conversion and storage devices. This reveals the importance and, indeed, the linchpin role of nanomaterial synthesis for current nanotechnology and high-performance functional devices. In this review, we provide an overview of the synthesis strategies for design- ing metal oxide nanomaterials in zero-dimensional （0D）, one-dimensional （1D）, two-dimensional （2D）, and three-di- mensional （3D） forms, particularly of the selected typical metal oxides TiO2, SnO2 and ZnO. The pros and cons of the typical synthetic methods and experimental protocols are reviewed and outlined. This comprehensive review gives a broad overview of the synthetic strategies for designing ＂property-on-demand＂ metal oxide nanostructures to fur- ther advance current nanoscience and nanotechnology.展开更多
Superhydrophobic and superhydrophilic surfaces have been extensively inves- tigated due to their importance for industrial applications. It has been reported, however, that superhydrophobic surfaces are very sensitive...Superhydrophobic and superhydrophilic surfaces have been extensively inves- tigated due to their importance for industrial applications. It has been reported, however, that superhydrophobic surfaces are very sensitive to heat, ultraviolet （UV） light, and electric potential, which interfere with their long-term durability. In this study, we introduce a novel approach to achieve robust superhydrophobic thin films by designing architecture-defined complex nanostructures. A family of ZnO hollow microspheres with controlled constituent architectures in the morphologies of 1D nanowire networks, 2D nanosheet stacks, and 3D mesoporous nanoball blocks, respectively, was synthesized via a two-step self-assembly approach, where the oligomers or the constituent nanostructures with specially designed structures are first formed from surfactant templates, and then further assembled into complex morphologies by the addition of a second co-surfactant. The thin films composed of two-step synthesized ZnO hollow microspheres with different architectures presented superhydrophobicities with contact angles of 150°-155°, superior to the contact angle of 103° for one-step synthesized ZnO hollow microspheres with smooth and solid surfaces. Moreover, the robust superhydrophobicity was further improved by perfluorinated silane surface modification. The perfluorinated silane treated ZnO hollow microsphere thin films maintained excellent hydrophobicity even after 75 h of UV irradiation. The realization of environmentally durable promising solution for their long-term irradiations. superhydrophobic surfaces provides a service under UV or strong solar light展开更多
in this report, we compared transcriptomic differ- ences between a synthetic Populus section Tacamahaca triploid driven by second-division restitution and its parents using a high-throughput RNA-seq method. A total of...in this report, we compared transcriptomic differ- ences between a synthetic Populus section Tacamahaca triploid driven by second-division restitution and its parents using a high-throughput RNA-seq method. A total of 4,080 genes were differentially expressed between the high-growth vigor allotriploids （SDR-H） and their parents, and 719 genes were non-additively expressed in SDR-H. Differences in gene expres- sion between the allotriploid and male parent were more significant than those between the allotriploid and female parent, which may be caused by maternal effects. We observed 3,559 differentially expressed genes （DEGs） between the SDR-H and male parent. Notably, the genes were mainly involved in metabolic process, cell proliferation, DNA methylation, cell division, and meristem and developmental growth. Among the 1,056 DEGs between SDR-H and female parent, many genes were associated with metabolic process and carbon utilization. In addition, 1,789 DEGs between high- and low-growth vigorallotriploid were mainly associated with metabolic process, auxin poplar transport, and regulation of meristem growth. Our results indicated that the higher poplar ploidy level can generate extensive transcriptomic diversity compared with its parents. Overall, these results increased our understanding of the driving force for phenotypic variation and adaptation in allopolyploids driven by second-division restitution.展开更多
基金supported by Australian Research Council Discovery Projects(DP230101625 and DP200103568)Australian Research Council Future Fel owships(FT180100387 and FT160100281)QUT ECR Scheme Grant(no.2020001179)
文摘Metal exsolution engineering has been regarded as a promising strategy for activating intrinsically inert perovskite oxide catalysts toward efficient oxygen evolution reaction.Traditional metal exsolution processes on perovskites are often achieved by using the reducing hydrogen gas;however,this is not effective for the relatively stable phase,such as Ruddlesden-Popper perovskite oxides.To address this issue,triphenylphosphine is proposed to be a reduction promotor for accelerating the reduction and migration of the target metal atoms,aiming to achieve the effective exsolution of metallic species from Ruddlesden-Popper-type parent perovskites.Upon oxygen evolution reaction,these exsolved metallic aggregates are reconstructed into oxyhydroxides as the real active centers.After further modification by lowpercentage iridium oxide nanoclusters,the optimal catalyst delivered an overpotential as low as 305 mV for generating the density of 10 mA cm^(-2),outperforming these reported noble metal-containing perovskite-based alkaline oxygen evolution reaction electrocatalysts.This work provides a potential approach to activate catalytically inert oxides through promoting surface metal exsolution and explores a novel class of Ruddlesden-Poppertype oxides for electrocatalytic applications.
基金supported in part by the National Key R&D Program of China (No. 2023YFA1606401)CAS Project for Young Scientists in Basic Research (No. YSBR-002)+3 种基金Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB34000000)the NSFC (Nos. 12305126, 12135017, 12121005)the support from the Youth Innovation Promotion Association of the Chinese Academy of Sciences (No. 2021419)the support from the Yong Scholar of Regional Development,CAS (No.[2023]15)
文摘In conventional isochronous mass spectrometry(IMS)performed on a storage ring,the precision of mass measurements for short-lived nuclei depends on the accurate determination of the revolution times(T)of stored ions.However,the resolution of T inevitably deteriorates due to the magnetic rigidity spread of the ions,limiting the mass-resolving power.In this study,we used the betatron tunes Q(the number of betatron oscillations per revolution)of the ions and established a correlation between T and Q.From this correlation,T was transformed to correspond to a fixed Q with higher resolution.Using these transformed T values,the masses of ^(63)Ge,^(65)As,^(67)Se,and ^(71)Kr agreed well with the mass values measured using the newly developed IMS(Bρ-IMS).We also studied the systematics of Coulomb displacement energies(CDEs)and found that anomalous staggering in CDEs was eliminated using new mass values.This method of T transformation is highly effective for conventional IMS equipped with a single time-of-flight detector.
基金supported by grants from the National Natural Science Foundation of China(No.81760154,No.31600677)Guangxi Natural Science Foundation ( No. 2017JJA10168)Guangxi University Student Innovation and Entrepreneurship Training Program (No.201710598006,No.20180598030)
基金supported by Natural Science Foundation of China[grant numbers 81760188]Scientific Research Fund of Guangxi Provincial Education Department [grant numbers 2017KY0103 (02601217023C)]
文摘To characterize the patterns of ABR waves in tree shrews, we must understand the hearing sensitivity and auditory function of healthy adult tree shrews. Fifteen tree shrews(30 ears) were stimulated with clicks and tone-pips at 11 different frequencies from 1 to 60 kHz. The ABR waves were recorded and analyzed. The ABR consisted of five to seven positive waves in the first 10 ms after a click stimulus, and the average hearing threshold of component III was 27.86 ± 3.78 dB SPL. Wave III was the largest and most clear. The ABR threshold was related to the tone-pip sitmulus by a "U" shaped curve. The sensitive frequency was approximately 8 kHz in tree shrews. The latencies systematically decreased with increasing stimulus frequencies. The ABR amplitudes of wave III increased as the sound pressure level increased. All of these results provide an empirical basis for future studies of hearing diseases in tree shrews.
基金This work was financially supported by the Australian Research Council(ARC)through Future Fellowship grants(FT180100387 and FT160100281)Discovery Projects(DP200103568,DP210100472,and DP200102546)+1 种基金WL thanks the support of the Science and Technology Commission of Shanghai Municipality(19520713200)Open access funding provided by Shanghai Jiao Tong University
文摘Oxygen vacancies(Vo)in electrocatalysts are closely correlated with the hydrogen evo-lution reaction(HER)activity.The role of vacancy defects and the effect of their concentration,how-ever,yet remains unclear.Herein,Bi2O3,an unfavorable electrocata-lyst for the HER due to a less than ideal hydrogen adsorption Gibbs free energy(ΔGH*),is utilized as a perfect model to explore the func-tion of Vo on HER performance.Through a facile plasma irradia-tion strategy,Bi2O3 nanosheets with different Vo concentrations are fabricated to evaluate the influence of defects on the HER process.Unexpectedly,while the generated oxygen vacancies contribute to the enhanced HER performance,higher Vo concentrations beyond a saturation value result in a significant drop in HER activity.By tunning the Vo concentration in the Bi_(2)O_(3)nanosheets via adjusting the treatment time,the Bi2O3 catalyst with an optimized oxygen vacancy concentration and detectable charge carrier concentration of 1.52×10^(24)cm^(−3)demonstrates enhanced HER performance with an overpotential of 174.2 mV to reach 10 mA cm^(−2),a Tafel slope of 80 mV dec−1,and an exchange current density of 316 mA cm−2 in an alkaline solution,which approaches the top-tier activity among Bi-based HER electrocatalysts.Density-functional theory calculations confirm the preferred adsorption of H*onto Bi2O3 as a function of oxygen chemical potential(ΔμO)and oxygen partial potential(PO2)and reveal that high Vo concentrations result in excessive stability of adsorbed hydrogen and hence the inferior HER activity.This study reveals the oxygen vacancy concentration-HER catalytic activity relationship and provides insights into activating catalytically inert materials into highly efficient electrocatalysts.
基金This work was supported by the National Key R&D Program of China(Nos.2016YFA0400504 and 2018YFA0404401)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB34000000)+4 种基金the National Natural Science Foundation of China(Nos.11905261,11805032,11975280,and 11605248)the CAS "Light of West China" Program,the China Postdoctoral Science Foundation(No.2019M660250)the FRIB-CSC Fellowship,China(No.201704910964)the International Postdoctoral Exchange Fellowship Program 2017 by the Office of China Postdoctoral Council(No.60 Document of OCPC,2017)the European Research Council(ERC)under the European Union’s Horizon 2020 Research and Innovation Programme(No.682841 "ASTRUm").
文摘Isochronous mass spectrometry(IMS)of heavyion storage rings is a powerful tool for the mass measurements of short-lived nuclei.In IMS experiments,masses are determined through precision measurements of the revolution times of the ions stored in the ring.However,the revolution times cannot be resolved for particles with nearly the same mass-to-charge(m/q)ratios.To overcome this limitation and to extract the accurate revolution times for such pairs of ion species with very close m/q ratios,in our early work on particle identification,we analyzed the amplitudes of the timing signals from the detector based on the emission of secondary electrons.Here,the previous data analysis method is further improved by considering the signal amplitudes,detection efficiencies,and number of stored ions in the ring.A sensitive Z-dependent parameter is introduced in the data analysis,leading to a better resolution of ^(34)Ar^(18+) and ^(51)Co^(27+) with A/Z=17/9.The mean revolution times of ^(34)Ar^(18+) and ^(51)Co^(27+) are deduced,although their time difference is merely 1.8 ps.The uncorrected,overlapped peak of these ions has a full width at half maximum of 7.7 ps.The mass excess of ^(51)Co was determined to be-27;332e41T keV,which is in agreement with the previous value of-27;342e48T keV.
基金supported by Australian Research Council (ARC) through an ARC Discovery Project (DP200103568)two ARC Future Fel owship projects (FT180100387 and FT160100281)+1 种基金the financial support by a QUT 2020 ECR Scheme Grant (No. 2020001179)the project mentorship provided by Prof. Godwin Ayoko
文摘Two-dimensional/two-dimensional(2D/2D)heterostructures consisting of two or more 2D building blocks possess intriguing electronic features at the nanosized interfacial regions,endowing the possibility for effectively modulating the confinement,and transport of charge carriers,excitons,photons,phonons,etc.to bring about a wide range of extraordinary physical,chemical,thermal,and/or mechanical properties.By rational design and synthesis of 2D/2D heterostructures,electrochemical properties for advanced batteries and electrocatalysis can be well regulated to meet some practical requirements.In this review,a summary on the commonly employed synthetic strategies for 2D/2D heterostructures is first given,followed by a comprehensive review on recent progress for their applications in batteries and various electrocatalysis reactions.Finally,a critical outlook on the current challenges and promising solutions is presented,which is expected to offer some insightful ideas on the design principles of advanced 2D-based nanomaterials to address the current challenges in sustainable energy storages and green fuel generations.
基金supported by an Australian Research Council(ARC)Discovery Early Career Researcher Award(DECRA)project(DE150100280)an ARC Discovery Project(DP160102627)an ARC Future Fellowship Project(FT160100281)
文摘Two-dimensional（2D） metal oxide nanosheets have attracted much attention as potential electrode materials for rechargeable batteries in recent years. This is primarily due to their natural abundance, environmental compatibility, and low cost as well as good electrochemical properties. Despite the fact that most metal oxides possess low conductivity, the introduction of some conductive heterogeneous components, such as nano-carbon, carbon nanotubes（CNTs）, and graphene, to form metal oxide-based hybrids,can effectively overcome this drawback. In this mini review, we will summarize the recent advances of three typical 2D metal oxide nanomaterials, namely, binary metal oxides, ternary metal oxides, and hybrid metal oxides, which are used for the electrochemical applications of next-generation rechargeable batteries, mainly for lithium-ion batteries（LIBs） and sodium-ion batteries（SIBs）. Hence, this review intends to functionalize as a good reference for the further research on 2D nanomaterials and the further development of energy-storage devices.
基金This work was supported by the Fundamental Research Funds for the Central Universities(2232021A-02 and 2232023Y-01)the National Natural Science Foundation of China(Nos.52122312,22209024 and 22202183).
文摘Electrochemical reduction of CO_(2)into high-value hydrocarbons and alcohols by using Cu-based catalysts is a promising and attractive technology for CO_(2)capture and utilization,resulting from their high catalytic activity and selectivity.The mobility and accessibility of active sites in Cubased catalysts significantly hinder the development of efficient Cu-based catalysts for CO_(2)electrochemical reduction reaction(CO_(2)RR).Herein,a facile and effective strategy is developed to engineer accessible and structural stable Cu sites by incorporating single atomic Cu into the nitrogen cavities of the host graphitic carbon nitride(g-C_(3)N_(4))as the active sites for CO_(2)-to-CH_(4)conversion in CO_(2)RR.By regulating the coordination and density of Cu sites in g-C_(3)N_(4),an optimal catalyst corresponding to a one Cu atom in one nitrogen cavity reaches the highest CH_(4)Faraday efficiency of 49.04%and produces the products with a high CH_(4)/C_(2)H_(4)ratio over 9.This work provides the first experimental study on g-C_(3)N_(4)-supported single Cu atom catalyst for efficient CH_(4)production from CO_(2)RR and suggests a principle in designing highly stable and selective high-efficiency Cu-based catalysts for CO_(2)RR by engineering Cu active sites in 2D materials with porous crystal structures.
基金This research was supported by the National Key R&D Program of China during the 14th Five-year Plan Period(2021YFD2200105).
文摘Poplar is an important afforestation and urban greening species.Poplar leaf development occurs in stages,from young to mature and then from mature to senescent;these are accompanied by various phenotypic and physiological changes.However,the associated transcriptional regulatory network is relatively unexplored.We first used principal component analysis to classify poplar leaves at different leaf positions into two stages:developmental maturity(the stage of maximum photosynthetic capacity);and the stage when photosynthetic capacity started to decline and gradually changed to senescence.The two stages were then further subdivided into five intervals by gene expression clustering analysis:young leaves,the period of cell genesis and functional differentiation(L1);young leaves,the period of development and initial formation of photosynthetic capacity(L3-L7);the period of maximum photosynthetic capacity of functional leaves(L9-L13);the period of decreasing photosynthetic capacity of functional leaves(L15-L27);and the period of senescent leaves(L29).Using a weighted co-expression gene network analysis of regulatory genes,high-resolution spatiotemporal transcriptional regulatory networks were constructed to reveal the core regulators that regulate leaf development.Spatiotemporal transcriptome data of poplar leaves revealed dynamic changes in genes and miRNAs during leaf development and identified several core regulators of leaf development,such as GRF5 and MYB5.This in-depth analysis of transcriptional regulation during leaf development provides a theoretical basis for exploring the biological basis of the transcriptional regulation of leaf development and the molecular design of breeding for delaying leaf senescence.
文摘Based on the idea of infinitesimal analysis, we establish the basic model of relation between speed and flow. Since putting a certain amount of self-driving car will affect the average speed of mixed traffic flow, we choose the proportion of self-driving car to be a variable, denoted by k. Based on the least square method, we find two critical values of k that are 38.63% and 68.26%. When k 38.63%, the self-driving cars have a negative influence to the traffic. When 38.63% < k < 68.26%, they have a positive influence to the traffic. When k > 68.26%, they have significant improvement to the traffic capacity of the road.
文摘Based on the entropy weight method and the gray relational analysis method, we first calculate the weight of each index and the correlation coefficient between the indicators, get the urban intelligent growth index, and then calculate the annual growth rate of the composite index. We find the following results. First, Suzhou to improve its environment, the success rate of 109.67%. Saint Louis to improve its economy, the growth rate of 57.4%. Second, the sensitivity of the data analysis, each of the indicators is increased by 10%, 20%, 30%, other indicators remain unchanged. Recalculate the city’s intelligent growth index, we find that the greater the volatility, the greater the potential. The total population of the city, built green area, the total length of the bus operating a greater potential, built-up area, the smallest regional GDP potential. Finally, we propose an improved model combining remote sensing with GIS to analyze urban expansion and farmland loss from time and space qualitatively and quantitatively.
基金support of the Australian Research Council under Discovery Projects DP210100721 and DP210100331.
文摘Two-dimensional (2D) heterostructures have shown great potential in advanced photovoltaics due to their restrained carrier recombination, prolonged exciton lifetime and improved light absorption. Herein, a 2D polarized heterostructure is constructed between Janus MoSSe and MoTe_(2) monolayers and is systematically investigated via first-principles calculations. Electronically, the valence band and conduction band of the MoSSe−MoTe_(2) (MoSeS−MoTe_(2)) are contributed by MoTe_(2) and MoSSe layers, respectively, and its bandgap is 0.71 (0.03) eV. A built-in electric field pointing from MoTe_(2) to MoSSe layers appears at the interface of heterostructures due to the interlayer carrier redistribution. Notably, the band alignment and built-in electric field make it a direct z-scheme heterostructure, benefiting the separation of photogenerated electron-hole pairs. Besides, the electronic structure and interlayer carrier reconstruction can be readily controlled by reversing the electric polarization of the MoSSe layer. Furthermore, the light absorption of the MoSSe/MoTe_(2) heterostructure is also improved in comparison with the separated monolayers. Consequently, in this work, a new z-scheme polarized heterostructure with polarization-controllable optoelectronic properties is designed for highly efficient optoelectronics.
基金supported by the Australian Research Council through ARC Discovery Projects(DP200103568 and DP230101625)ARC Future Fellowship projects(FT180100387 and FT160100281).
文摘Active metal-based batteries are drawing increased attention because of their inherent high energy density and specific capacity.Some grand challenges,such as dendrite growth,electrode degradation,rapid performance fading,etc.,have limited their practical application.Bioinspiration,which involves taking cues from the structures and functions of the natural world,can lead to a wealth of conceptually fresh approaches to regulator the metal ion transportation to achieve a dendrite-free metal plating,thwart the side-reaction reactions,and retard the structural distortions,for a more reliable and secure operation of active metal-based batteries.In this review,we concentrate on the fabrication and application of bioinspired designs in active metal-based batteries with enhanced performance,along with discussion on the challenges and opportunities associated with this promising topic.We anticipate that this review can offer some insights into the development of functional materials by learning from nature and provide some approaches for the innovations of either the battery structures or the energy materials for metal-based batteries.
基金the financial support from the National Natural Science Foundation of China(No.22005147).
文摘Porous carbons(PCs)are one of the promising electrode materials for supercapacitors attributed to their low cost,superior electronic conductivity,easy availability,and tailored pore structures.Template methods have been explored as the effective strategies for the fabrication of PCs with desirable morphology and highly controllable pore size distribution.Herein,this review firstly focuses on design and synthetic mechanism of various PCs via hard templates,soft templates,and dual-templates.Secondly,an overview of PCs is presented with a detailed discussion of the structure-activity relationship between electrochemical performances and pore structures.Thirdly,the current challenges and prospects of template-assisted synthesis of PCs for supercapacitors are highlighted regarding further researches.
基金supported by Australian Research Council Discovery Early Career Researcher Award(ARC-DECRA,DE150100280)
文摘There has been exponential growth in research activities on nanomaterials and nanotechnology for appli- cations in emerging technologies and sustainable energy in the past decade. The properties of nanomaterials have been found to vary in terms of their shapes, sizes, and number of nanoscale dimensions, which have also further boosted the performance of nanomaterial-based electronic, catalytic, and sustainable energy conversion and storage devices. This reveals the importance and, indeed, the linchpin role of nanomaterial synthesis for current nanotechnology and high-performance functional devices. In this review, we provide an overview of the synthesis strategies for design- ing metal oxide nanomaterials in zero-dimensional （0D）, one-dimensional （1D）, two-dimensional （2D）, and three-di- mensional （3D） forms, particularly of the selected typical metal oxides TiO2, SnO2 and ZnO. The pros and cons of the typical synthetic methods and experimental protocols are reviewed and outlined. This comprehensive review gives a broad overview of the synthetic strategies for designing ＂property-on-demand＂ metal oxide nanostructures to fur- ther advance current nanoscience and nanotechnology.
基金Acknowledgements This work was supported by the Australian Research Council （ARC） Discovery Project No. DP1096546. ZQS was supported by an ARC Postdoctoral （APD） Research Fellowship and a University of Wollongong （UOW） Vice-chancellor＇s Research Fellowship. TL acknowledges the support of a University of Queensland （UQ） Postdoctoral Fellowship. KSL and LJ appreciate the financial support of the National Natural Science Foundation of China （Nos. 21273016, 21001013, and 20974113）, the National Basic Research Program of China （No. 2013CB933003）, the Program for New Century Excellent Talents in Universities, Beijing Natural Science Foundation （No. 2122035）, and the Key Research Program of the Chinese Academy of Sciences （No. KJZDEW-M01）.
文摘Superhydrophobic and superhydrophilic surfaces have been extensively inves- tigated due to their importance for industrial applications. It has been reported, however, that superhydrophobic surfaces are very sensitive to heat, ultraviolet （UV） light, and electric potential, which interfere with their long-term durability. In this study, we introduce a novel approach to achieve robust superhydrophobic thin films by designing architecture-defined complex nanostructures. A family of ZnO hollow microspheres with controlled constituent architectures in the morphologies of 1D nanowire networks, 2D nanosheet stacks, and 3D mesoporous nanoball blocks, respectively, was synthesized via a two-step self-assembly approach, where the oligomers or the constituent nanostructures with specially designed structures are first formed from surfactant templates, and then further assembled into complex morphologies by the addition of a second co-surfactant. The thin films composed of two-step synthesized ZnO hollow microspheres with different architectures presented superhydrophobicities with contact angles of 150°-155°, superior to the contact angle of 103° for one-step synthesized ZnO hollow microspheres with smooth and solid surfaces. Moreover, the robust superhydrophobicity was further improved by perfluorinated silane surface modification. The perfluorinated silane treated ZnO hollow microsphere thin films maintained excellent hydrophobicity even after 75 h of UV irradiation. The realization of environmentally durable promising solution for their long-term irradiations. superhydrophobic surfaces provides a service under UV or strong solar light
基金supported in part by Special Fund for Forest Scientific Research in the Public Welfare (201404113)a Foundation for the Author of National Excellent Doctoral Dissertation of P. R. China (201267)111 Project (B13007)
文摘in this report, we compared transcriptomic differ- ences between a synthetic Populus section Tacamahaca triploid driven by second-division restitution and its parents using a high-throughput RNA-seq method. A total of 4,080 genes were differentially expressed between the high-growth vigor allotriploids （SDR-H） and their parents, and 719 genes were non-additively expressed in SDR-H. Differences in gene expres- sion between the allotriploid and male parent were more significant than those between the allotriploid and female parent, which may be caused by maternal effects. We observed 3,559 differentially expressed genes （DEGs） between the SDR-H and male parent. Notably, the genes were mainly involved in metabolic process, cell proliferation, DNA methylation, cell division, and meristem and developmental growth. Among the 1,056 DEGs between SDR-H and female parent, many genes were associated with metabolic process and carbon utilization. In addition, 1,789 DEGs between high- and low-growth vigorallotriploid were mainly associated with metabolic process, auxin poplar transport, and regulation of meristem growth. Our results indicated that the higher poplar ploidy level can generate extensive transcriptomic diversity compared with its parents. Overall, these results increased our understanding of the driving force for phenotypic variation and adaptation in allopolyploids driven by second-division restitution.
