The vibrational motions are usually neglected when calculating(e,2e) triple differential cross sections(TDCSs) of molecules. Here, multi-center distorted-wave method(MCDW) has been modified by including molecular vibr...The vibrational motions are usually neglected when calculating(e,2e) triple differential cross sections(TDCSs) of molecules. Here, multi-center distorted-wave method(MCDW) has been modified by including molecular vibrations. This vibrational MCDW method is employed to calculate the TDCSs of 1b3gorbital of ethylene at low(100 eV) and medium(250 eV) incident electron energies in coplanar asymmetric kinematic condition. The results show that molecular vibrations significantly influence the angular distributions of the TDCSs, especially in the binary region along momentum transfer near the Bethe ridge.展开更多
Polymeric materials which can undergo controlled degradation and recycling are of great significance for a sustainable society.Although tremendous progress has been made in the degradation and recycling of both thermo...Polymeric materials which can undergo controlled degradation and recycling are of great significance for a sustainable society.Although tremendous progress has been made in the degradation and recycling of both thermoplastic and thermoset plastics,the development of high-performance degradable polymer adhesives is rare.Here,we have prepared high-performance nucleobase-containing thioctic acid-based supramolecular polymer adhesives through free radical polymerization.The specific hydrogen-bonding interactions between complementary nucleobases greatly improve the weak cohesion of the thioctic acid-based polymers and enhance the environmental stability of the thioctic acidbased polymers simultaneously.Degradation of the nucleobase-containing thioctic acid-based supramolecular polymers is achieved by the reduction of the disulfide backbone,and the cycle of degradation and repolymerization is further achieved via oxidative polymerization.The adhesion strength of the nucleobase-containing thioctic acid-based supramolecular polymers after two cycles of degradation and repolymerization still reaches as high as 4.7±0.3 MPa.This work provides an approach for the development of environmentally stable and high-performance degradable thioctic acid-based adhesives.展开更多
The slow kinetics of the cathode CO_(2) reduction reaction and the decomposition reaction of Li2CO3,a widebandwidth insulating product,lead to difficult CO_(2) capture and high charging potential in Li-CO_(2) batterie...The slow kinetics of the cathode CO_(2) reduction reaction and the decomposition reaction of Li2CO3,a widebandwidth insulating product,lead to difficult CO_(2) capture and high charging potential in Li-CO_(2) batteries.To improve the reaction kinetics and decrease the reaction overpotential,we synthesized mesoporous Pt nanosheets with high tensile strain.The presence of many unsaturated coordinated Pt atoms around the pores gives rise to tensile strain in the mesoporous Pt nanosheets.This tensile strain plays a key role in regulating the interactions between the catalytic surface of Pt and the adsorbed intermediates.The two-dimensional structure provides more active sites on the surface for the catalytic reactions.These superiorities enable a low overpotential of 0.36 V at a cutoff capacity of 100μAh·cm^(−2) at a current density of 10μA·cm^(−2) over more than 2000 h.This study opens new possibilities for the rational design of metal-based materials with strain engineering for electrochemical energy storage.展开更多
Protein biosynthesis by the ribosome is a fundamental biological process in living systems.Recent studies suggest that ribosomal subunits also play essential roles in cell growth and differentiation beyond their roles...Protein biosynthesis by the ribosome is a fundamental biological process in living systems.Recent studies suggest that ribosomal subunits also play essential roles in cell growth and differentiation beyond their roles in protein translation.The ribosomal subunit RPS6 has been studied for more than 50 years in various organisms,but little is known about its specific roles in certain signaling pathways.In this study,we focused on the functions of Arabidopsis RPS6A in auxin-related root growth and development.The rps6a mutant presented a series of auxin-deficient phenotypes,such as shortened primary roots,reduced lateral root numbers,and defective vasculatures.Treatment of the rps6a mutant with various concentrations of auxin and its analogs did not restore the root defect phenotypes,suggesting a defect in the auxin signaling pathway.Further cell biological and global transcriptome analyses revealed that auxin signaling was weakened in the rps6a mutant and that there was a reduced abundance of PIN-FORMED(PIN)auxin transporters.Our work provides insights into the role of the protein biosynthesis pathway involved in auxin signaling.展开更多
V_(2)O_(5)·nH_(2)O has been widely studied for aqueous zinc-ion batteries.The intercalation of inorganic ions has been used as a feasible method to improve the capacity of vanadium pentoxide.To further improve th...V_(2)O_(5)·nH_(2)O has been widely studied for aqueous zinc-ion batteries.The intercalation of inorganic ions has been used as a feasible method to improve the capacity of vanadium pentoxide.To further improve the stability,organic small molecule choline chloride intercalation is used to expand the spacing of the vanadium pentoxide layers and increase the cycling stability.Therefore,we consider the introduction of Sr^(2+)to cointercalate with choline chloride.Here,we synthes-ized vanadium pentoxide cointercalated with Sr^(2+)and choline ions(Ch^(+))via a simple hydrothermal method.The electro-chemical performance shows an enhanced cathode capacitance contribution of Sr&Ch-V_(2)O_(5),with a discharge capacity of 526 mAh·g^(-1)at 0.1 A·g^(-1)and a retention rate of 78.9%after 2000 cycles at 5 A·g^(-1).This work offers a novel strategy for the design of organic‒inorganic hybrid materials for use as cathodes in aqueous zinc-ion batteries.展开更多
The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)...The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.展开更多
Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thal...Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thaliana,the OSCA family has been identified as mechanically activated ion channels that respond to osmotic stress by allowing calcium ions to enter the cell.This influx increases the cytoplasmic calcium concentration,triggering osmotic stress-induced signal transduction cascades in plants.In this study,we determined the structures of OSCA2.2 and OSCA3.1 via cryoelectron microscopy(cryo-EM).Both proteins form homodimers consisting of 11 transmembrane helices(TM1–11).The ion conduction pathway is formed by TM4–8.Despite belonging to the same family,OSCA2.2 and OSCA3.1 exhibit notable structural variations.Structural analysis revealed that both OSCA2.2 and OSCA3.1 exhibit a closed conformation.We also conducted functional studies on OSCA proteins via electrophysiological experiments and confirmed the role of key amino acids in the process of ion permeation.展开更多
Strain engineering serves as an effective approach for tuning the properties of transition metal oxides and their heterostructures. However, conventional epitaxial approaches are fundamentally constrained by the limit...Strain engineering serves as an effective approach for tuning the properties of transition metal oxides and their heterostructures. However, conventional epitaxial approaches are fundamentally constrained by the limited choice of substrates, which restricts the ability to achieve continuous strain modulation. The emergence of freestanding oxide thin films has significantly expanded the scope of strain manipulation, allowing the application of larger tensile strains and the induction of novel functionalities. Nevertheless, current freestanding film technologies face a critical limitation: strain modulation has so far been confined to tensile strain, while the application of compressive strain remains inaccessible. To overcome this challenge, we designed a symmetric tri-layer structure composed of clamping layer/nickelate/clamping layer, which enables modulation of the metal-insulator transition in freestanding Nd NiO_(3) and La NiO_(3) thin films under both tensile and compressive strain. This clamping-layermediated strain engineering approach can be readily generalized to other freestanding oxide systems, providing a versatile platform for manipulating the physical properties of freestanding thin films.展开更多
Double-resonance Raman(DRR)scattering in two-di-mensional(2D)materials describes the intravalley or intervalley scattering of an electron or a hole excited by incident photons.Although the presence of defects can prov...Double-resonance Raman(DRR)scattering in two-di-mensional(2D)materials describes the intravalley or intervalley scattering of an electron or a hole excited by incident photons.Although the presence of defects can provide additional momentum and influence the scat-tering process involving one or two phonons,only the idealized defects without any structural details are considered in tra-ditional DRR theory.Here,the second-order DRR spectra of WSe_(2) monolayer with different types of defects are calculated involving the combinations of acoustic and optical phonons in the vicinity of K(K')and M points of the Brillouin zone.The electronic band structures are modified due to the presence of defects,and the band unfolding method is adopted to show the bending of valence and conduction bands for the defective WSe_(2) monolayers.The associ-ated phononic band structures also exhibit different changes in phonon dispersion curves,re-sulting in different DRR spectra corresponding to the different types of defects in the WSe_(2) monolayers.For example,the existence of W vacancy in the WSe_(2) monolayer would result in downshifts in vibrational frequencies and asymmetrical broadenings in linewidths for most combination modes due to the dramatic changes in contour shape of electronic valleys at K and K'.Moreover,the scattering from K to Q is found to be forbidden for the two Se vacan-cies because of the elevation of conduction band at the Q point.Our work highlights the role of defect structures in the intervalley scattering and may provide better understanding in the underlying physics of DRR process in 2D materials.展开更多
Phosphoric acid/phosphate solu-tions are commonly used as buffer solutions in the fundamental stud-ies in electrochemistry.Informa-tion on the nature of adsorbed(bi)phosphate as well as the do-main structures is of gr...Phosphoric acid/phosphate solu-tions are commonly used as buffer solutions in the fundamental stud-ies in electrochemistry.Informa-tion on the nature of adsorbed(bi)phosphate as well as the do-main structures is of great impor-tance in unveiling the impact on electrochemical processes occur-ring at electrode electrolyte interface.In this work,the pH effect on the adsorption of phosphate related species on Pd(111)electrode has been investigated by cyclic voltammetry over a broad pH range from 1 to 14.Af-ter carefully analyzing the related onset desorption potential of(bi)phosphate adsorbate to the thermodynamic equilibrium potential of the corresponding electrode reactions,three dif-ferent phosphate related adsorbates have been identified,which are highly pH-dependent.Our analysis reveals that the dominant phosphate anions in bulk solution undergo deprotona-tion upon adsorption.At pH<1.5,the main adsorbate on Pd(111)is;H_(2)PO_(4)^(λ_(1)^(-))in solutions with 1.5<pH<7,the main adsorbate changes into.HPO_(4)^(λ_2^(-))At higher pHs,PO_(4)^(λ_(3)^(-))on electrode surface dominates.The exact charging value ofλ_(i),which represents the true va-lence of the(bi)phosphate adsorbate,could be determined using theoretical calculations.In addition,our results can not rule out the possibility of co-adsorbed H_(3)PO_(4)molecules on Pd(111)at pH<1.5,which needs to be proved by infrared spectroscopy in the future.展开更多
By simplifying catalyst-product separation and reducing phosphorus waste,heterogeneous hydroformylation offers a more sustainable alternative to homogeneous processes.However,heterogeneous hydroformylation catalysts d...By simplifying catalyst-product separation and reducing phosphorus waste,heterogeneous hydroformylation offers a more sustainable alternative to homogeneous processes.However,heterogeneous hydroformylation catalysts developed thus far still suffer from the issues of much lower activity and metal leaching,which severely hinder their practical application.Here,we demonstrate that incorporating phosphorus(P)atoms into graphitic carbon nitride(PCN)supports facilitates charge transfer from Rh to the PCN support,thus largely enhancing electronic metal-support interactions(EMSIs).In the styrene hydroformylation reaction,the activity of Rh_(1)/PCN single-atom catalysts(SACs)with varying P contents exhibited a volcano-shaped relationship with P doping,where the Rh_(1)/PCN SAC with optimal P doping showed exceptional activity,approximately 5.8-and 3.3-fold greater than that of the Rh_(1)/g-C_(3)N_(4)SAC without P doping and the industrial homogeneous catalyst HRh(CO)(PPh_(3))_(3),respectively.In addition,the optimal Rh_(1)/PCN SAC catalyst also demonstrated largely enhanced multicycle stability without any visible metal aggregation owing to the increased EMSIs,which sharply differed from the severe metal aggregation of large nanoparticles on the Rh_(1)/g-C_(3)N_(4)SAC.Mechan-istic studies revealed that the enhanced catalytic performance could be attributed to electron-deficient Rh species,which reduced CO adsorption while simultaneously promoting alkene adsorption through increased EMSIs.These findings suggest that tuning EMSIs is an effective way to achieve SACs with high activity and durability.展开更多
The high activity and stability of intermetallic PtCo nanocatalysts toward oxygen reduction reaction make them a top candidate as low-Pt cathode catalysts in proton exchange membrane fuel cells(PEMFCs).However,forming...The high activity and stability of intermetallic PtCo nanocatalysts toward oxygen reduction reaction make them a top candidate as low-Pt cathode catalysts in proton exchange membrane fuel cells(PEMFCs).However,forming intermetallic structures typically requires high-temperature annealing,posing a challenge for achieving well-size control and highly ordered structures.Here we report the design and synthesis of bimetallic co re@shell structured precursors for affording high-performance intermetallic PtCo catalysts.The fabrication of the core@shell precursor involves using a molecular ligand containing both sulfur and oxygen donors to selectively bind with Pt colloidal nanoparticles as the core and chelate Co ions as the shell.During high-temperature annealing,the ligand transforms into carbon coatings around alloy nanoparticles,preventing particle sintering;meanwhile,Co ions in the shell can easily diffuse into the Pt core,which helps to increase the thermodynamic driving force for forming intermetallic structures.These benefits enable us to obtain the catalyst with finely dispersed nanoparticles(~3.5 nm)and a high ordering degree of 72%.With 0.1 mgPt/cm^(2)cathode loading,the catalyst delivers superior performance and durability in PEMFCs,showing an initial mass activity of 0.56 A/mgPt,an initial power density of 1.05 W/cm^(2)at 0.67 V(H_(2)-air),and a voltage loss of 26 mV at 0.8 A/cm^(2)after the accelerated durability test.展开更多
Along with the surging demand for energy storage devices,the cost and availability of the materials remain dominant factors in slowing down their industrial application.The repurposing of waste asphalt into high-perfo...Along with the surging demand for energy storage devices,the cost and availability of the materials remain dominant factors in slowing down their industrial application.The repurposing of waste asphalt into high-performance electrode materials is of significant interest,as it holds the potential to circumvent energy and environmental issues.Here,we report the controllable synthesis of asphalt-derived mesoporous carbon as an active material for electrocatalytic hydrogen gas capacitor(EHGC).The hierarchically porous carbon(HPC)with a high surface area of 1943.4 m^(2)·g^(-1)can operate in pH universal aqueous electrolytes in EHGC.It displays a specific energy and power density of 57 Wh·kg^(-1)and 554 W·kg^(-1)in neutral electrolyte as well as 52 Wh·kg^(-1)and 657 W·kg^(-1)in acidic electrolyte.Additionally,the charge storage mechanism of HPC-EHGC is studied with the help of Raman spectroscopy and X-ray photoelectron spectroscopy.Furthermore,the assembled HPC-EHGC device displays a discharge capacitance of 170 F·g^(-1)with an excellent capacitance retention rate of 100%up to 20000 cycles at 10 A·g^(-1)in acidic electrolyte.This work introduces a novel approach to converting waste asphalt into high-performance carbon for EHGC,achieving superior performance over commercial materials.By simultaneously addressing environmental waste issues and advancing energy storage technology,this study makes a significant contribution to sustainable materials science and next-generation battery development.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12004370 and 12127804)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB34020000)。
文摘The vibrational motions are usually neglected when calculating(e,2e) triple differential cross sections(TDCSs) of molecules. Here, multi-center distorted-wave method(MCDW) has been modified by including molecular vibrations. This vibrational MCDW method is employed to calculate the TDCSs of 1b3gorbital of ethylene at low(100 eV) and medium(250 eV) incident electron energies in coplanar asymmetric kinematic condition. The results show that molecular vibrations significantly influence the angular distributions of the TDCSs, especially in the binary region along momentum transfer near the Bethe ridge.
基金supported by the National Natural Science Foundation of China(Nos.22273098,22373003,22103002 and 52033001)the Key Project of Anhui Province Science and Technology Innovation Platform(No.202305a12020030)the financial support from the Anhui Provincial Natural Science Foundation(No.2408085Y004)。
文摘Polymeric materials which can undergo controlled degradation and recycling are of great significance for a sustainable society.Although tremendous progress has been made in the degradation and recycling of both thermoplastic and thermoset plastics,the development of high-performance degradable polymer adhesives is rare.Here,we have prepared high-performance nucleobase-containing thioctic acid-based supramolecular polymer adhesives through free radical polymerization.The specific hydrogen-bonding interactions between complementary nucleobases greatly improve the weak cohesion of the thioctic acid-based polymers and enhance the environmental stability of the thioctic acidbased polymers simultaneously.Degradation of the nucleobase-containing thioctic acid-based supramolecular polymers is achieved by the reduction of the disulfide backbone,and the cycle of degradation and repolymerization is further achieved via oxidative polymerization.The adhesion strength of the nucleobase-containing thioctic acid-based supramolecular polymers after two cycles of degradation and repolymerization still reaches as high as 4.7±0.3 MPa.This work provides an approach for the development of environmentally stable and high-performance degradable thioctic acid-based adhesives.
基金supported by the National Natural Science Foundation of China(52002366,22075263,22571288)the Fundamental Research Funds for the Central Universities(WK2060000091,WK2060250115,WK2060000039)the Students’Innovation and Entrepreneurship Foundation of USTC(CY2023C021).
文摘The slow kinetics of the cathode CO_(2) reduction reaction and the decomposition reaction of Li2CO3,a widebandwidth insulating product,lead to difficult CO_(2) capture and high charging potential in Li-CO_(2) batteries.To improve the reaction kinetics and decrease the reaction overpotential,we synthesized mesoporous Pt nanosheets with high tensile strain.The presence of many unsaturated coordinated Pt atoms around the pores gives rise to tensile strain in the mesoporous Pt nanosheets.This tensile strain plays a key role in regulating the interactions between the catalytic surface of Pt and the adsorbed intermediates.The two-dimensional structure provides more active sites on the surface for the catalytic reactions.These superiorities enable a low overpotential of 0.36 V at a cutoff capacity of 100μAh·cm^(−2) at a current density of 10μA·cm^(−2) over more than 2000 h.This study opens new possibilities for the rational design of metal-based materials with strain engineering for electrochemical energy storage.
基金supported by the National Natural Science Foundation of China(32321001)the Forestry Bureau of Anhui Province(AHLYJBGS-2024-01)+3 种基金the Center for Advanced Interdisciplinary Science and Biomedicine of IHM,the Division of Life Sciences and Medicine,the University of Science and Technology of China(QYPY20220012)the USTC Research Funds of the Double First-Class Initiative(YD9100002016)start-up funding from the University of Science and Technology of China and the Chinese Academy of Sciences(GG9100007007,KY9100000026,KY9100000051,KJ2070000079)the Fundamental Research Funds for the Central Universities(WK9100000021)。
文摘Protein biosynthesis by the ribosome is a fundamental biological process in living systems.Recent studies suggest that ribosomal subunits also play essential roles in cell growth and differentiation beyond their roles in protein translation.The ribosomal subunit RPS6 has been studied for more than 50 years in various organisms,but little is known about its specific roles in certain signaling pathways.In this study,we focused on the functions of Arabidopsis RPS6A in auxin-related root growth and development.The rps6a mutant presented a series of auxin-deficient phenotypes,such as shortened primary roots,reduced lateral root numbers,and defective vasculatures.Treatment of the rps6a mutant with various concentrations of auxin and its analogs did not restore the root defect phenotypes,suggesting a defect in the auxin signaling pathway.Further cell biological and global transcriptome analyses revealed that auxin signaling was weakened in the rps6a mutant and that there was a reduced abundance of PIN-FORMED(PIN)auxin transporters.Our work provides insights into the role of the protein biosynthesis pathway involved in auxin signaling.
文摘V_(2)O_(5)·nH_(2)O has been widely studied for aqueous zinc-ion batteries.The intercalation of inorganic ions has been used as a feasible method to improve the capacity of vanadium pentoxide.To further improve the stability,organic small molecule choline chloride intercalation is used to expand the spacing of the vanadium pentoxide layers and increase the cycling stability.Therefore,we consider the introduction of Sr^(2+)to cointercalate with choline chloride.Here,we synthes-ized vanadium pentoxide cointercalated with Sr^(2+)and choline ions(Ch^(+))via a simple hydrothermal method.The electro-chemical performance shows an enhanced cathode capacitance contribution of Sr&Ch-V_(2)O_(5),with a discharge capacity of 526 mAh·g^(-1)at 0.1 A·g^(-1)and a retention rate of 78.9%after 2000 cycles at 5 A·g^(-1).This work offers a novel strategy for the design of organic‒inorganic hybrid materials for use as cathodes in aqueous zinc-ion batteries.
基金supported in part by the National Natural Science Foundation of China(12174366)Fundamental Re-search Funds for the Central Universities(WK3450000005)the Anhui Provincial Natural Science Foundation(2108085MC93).
文摘The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water.However,some photocatalysts(e.g.,zinc oxide-based composites)are susceptible to pH-dependent dissolution in water,which can result in the loss of photocatalysts and additional environ-mental pollution.To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for pho-tocatalytic water disinfection,we prepared MoS_(2)/ZnO@CS composites via a precipitation method to encapsulate chitosan(CS)around MoS_(2)/ZnO.The amino groups in the CS molecules act as storerooms for hydrogen ions,which inhibits the dissolution of zinc oxide.In addition,the MoS_(2)/ZnO@CS composites exhibit high production of reactive oxygen species(ROS)and broad-spectrum antibacterial activity under simulated solar irradiation(0.1 W·cm^(-2)).This makes it an excellent antibacterial agent for solar disinfection in water treatment.
基金supported by the National Natural Science Foundation of China(32322041,W2412029,32321001,32471279)USTC Research Funds of the Double First-Class Initiative(YD9100002004,YD9100002020)+2 种基金Fundamental Research Funds for the Central Universities(WK9100000031)Research Funds of Center for Advanced Interdisciplinary Science and Biomedicine of IHM(QYPY20230034)the Natural Science Foundation of Anhui Province(2408085JX005).
文摘Mechanosensitive ion channels are essential for sensing and converting mechanical forces into electrical or chemical signals.These channels are widely distributed across bacteria,animals,and plants.In Arabidopsis thaliana,the OSCA family has been identified as mechanically activated ion channels that respond to osmotic stress by allowing calcium ions to enter the cell.This influx increases the cytoplasmic calcium concentration,triggering osmotic stress-induced signal transduction cascades in plants.In this study,we determined the structures of OSCA2.2 and OSCA3.1 via cryoelectron microscopy(cryo-EM).Both proteins form homodimers consisting of 11 transmembrane helices(TM1–11).The ion conduction pathway is formed by TM4–8.Despite belonging to the same family,OSCA2.2 and OSCA3.1 exhibit notable structural variations.Structural analysis revealed that both OSCA2.2 and OSCA3.1 exhibit a closed conformation.We also conducted functional studies on OSCA proteins via electrophysiological experiments and confirmed the role of key amino acids in the process of ion permeation.
基金supported by the National Key Research and Development Program of China (Grant No.2023YFA1406404)the National Natural Science Foundation of China (Grant Nos.12504152,52572144,12374094,and 12074365)+5 种基金China Postdoctoral Science Foundation (Grant No.2024M763130)the China Postdoctoral Science Foundation-Anhui joint Support Program (Grant No.2024T007AH)the Fundamental Research Funds for the Central Universities(Grant No.WK9990000158)Chinese Academy of Sciences Project for Young Scientists in Basic Research(Grant No.YSBR-084)Innovation Program for Quantum Science and Technology (Grant No.2024ZD0301300)Anhui Provincial Natural Science Foundation (Grant No.2308085MA15)。
文摘Strain engineering serves as an effective approach for tuning the properties of transition metal oxides and their heterostructures. However, conventional epitaxial approaches are fundamentally constrained by the limited choice of substrates, which restricts the ability to achieve continuous strain modulation. The emergence of freestanding oxide thin films has significantly expanded the scope of strain manipulation, allowing the application of larger tensile strains and the induction of novel functionalities. Nevertheless, current freestanding film technologies face a critical limitation: strain modulation has so far been confined to tensile strain, while the application of compressive strain remains inaccessible. To overcome this challenge, we designed a symmetric tri-layer structure composed of clamping layer/nickelate/clamping layer, which enables modulation of the metal-insulator transition in freestanding Nd NiO_(3) and La NiO_(3) thin films under both tensile and compressive strain. This clamping-layermediated strain engineering approach can be readily generalized to other freestanding oxide systems, providing a versatile platform for manipulating the physical properties of freestanding thin films.
基金supported by the National Natural Sci-ence Foundation of China(No.22174135,No.21790352)the National Key R&D Program of China(No.2021YFA1500500,No.2016YFA0200600)+4 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000)Anhui Initiative in Quantum Information Technologies(No.AHY090100)CAS Project for Young Scientists in Basic Research(No.YSBR-054)Innovation Program for Quantum Science and Technology(No.2021ZD0303301)the Fundamental Research Funds for the Central Universities.
文摘Double-resonance Raman(DRR)scattering in two-di-mensional(2D)materials describes the intravalley or intervalley scattering of an electron or a hole excited by incident photons.Although the presence of defects can provide additional momentum and influence the scat-tering process involving one or two phonons,only the idealized defects without any structural details are considered in tra-ditional DRR theory.Here,the second-order DRR spectra of WSe_(2) monolayer with different types of defects are calculated involving the combinations of acoustic and optical phonons in the vicinity of K(K')and M points of the Brillouin zone.The electronic band structures are modified due to the presence of defects,and the band unfolding method is adopted to show the bending of valence and conduction bands for the defective WSe_(2) monolayers.The associ-ated phononic band structures also exhibit different changes in phonon dispersion curves,re-sulting in different DRR spectra corresponding to the different types of defects in the WSe_(2) monolayers.For example,the existence of W vacancy in the WSe_(2) monolayer would result in downshifts in vibrational frequencies and asymmetrical broadenings in linewidths for most combination modes due to the dramatic changes in contour shape of electronic valleys at K and K'.Moreover,the scattering from K to Q is found to be forbidden for the two Se vacan-cies because of the elevation of conduction band at the Q point.Our work highlights the role of defect structures in the intervalley scattering and may provide better understanding in the underlying physics of DRR process in 2D materials.
基金supported by the National Natural Science Foundation of China(No.22172151)。
文摘Phosphoric acid/phosphate solu-tions are commonly used as buffer solutions in the fundamental stud-ies in electrochemistry.Informa-tion on the nature of adsorbed(bi)phosphate as well as the do-main structures is of great impor-tance in unveiling the impact on electrochemical processes occur-ring at electrode electrolyte interface.In this work,the pH effect on the adsorption of phosphate related species on Pd(111)electrode has been investigated by cyclic voltammetry over a broad pH range from 1 to 14.Af-ter carefully analyzing the related onset desorption potential of(bi)phosphate adsorbate to the thermodynamic equilibrium potential of the corresponding electrode reactions,three dif-ferent phosphate related adsorbates have been identified,which are highly pH-dependent.Our analysis reveals that the dominant phosphate anions in bulk solution undergo deprotona-tion upon adsorption.At pH<1.5,the main adsorbate on Pd(111)is;H_(2)PO_(4)^(λ_(1)^(-))in solutions with 1.5<pH<7,the main adsorbate changes into.HPO_(4)^(λ_2^(-))At higher pHs,PO_(4)^(λ_(3)^(-))on electrode surface dominates.The exact charging value ofλ_(i),which represents the true va-lence of the(bi)phosphate adsorbate,could be determined using theoretical calculations.In addition,our results can not rule out the possibility of co-adsorbed H_(3)PO_(4)molecules on Pd(111)at pH<1.5,which needs to be proved by infrared spectroscopy in the future.
基金supported by the Petrochemical Research Institute Foundation(21-CB-09-01)the National Natural Science Foundation of China(22302186,22025205)+1 种基金the China Postdoctoral Science Foundation(2022M713030,2023T160618)the Fundamental Research Funds for the Central Universities(WK2060000058,WK2060000038).
文摘By simplifying catalyst-product separation and reducing phosphorus waste,heterogeneous hydroformylation offers a more sustainable alternative to homogeneous processes.However,heterogeneous hydroformylation catalysts developed thus far still suffer from the issues of much lower activity and metal leaching,which severely hinder their practical application.Here,we demonstrate that incorporating phosphorus(P)atoms into graphitic carbon nitride(PCN)supports facilitates charge transfer from Rh to the PCN support,thus largely enhancing electronic metal-support interactions(EMSIs).In the styrene hydroformylation reaction,the activity of Rh_(1)/PCN single-atom catalysts(SACs)with varying P contents exhibited a volcano-shaped relationship with P doping,where the Rh_(1)/PCN SAC with optimal P doping showed exceptional activity,approximately 5.8-and 3.3-fold greater than that of the Rh_(1)/g-C_(3)N_(4)SAC without P doping and the industrial homogeneous catalyst HRh(CO)(PPh_(3))_(3),respectively.In addition,the optimal Rh_(1)/PCN SAC catalyst also demonstrated largely enhanced multicycle stability without any visible metal aggregation owing to the increased EMSIs,which sharply differed from the severe metal aggregation of large nanoparticles on the Rh_(1)/g-C_(3)N_(4)SAC.Mechan-istic studies revealed that the enhanced catalytic performance could be attributed to electron-deficient Rh species,which reduced CO adsorption while simultaneously promoting alkene adsorption through increased EMSIs.These findings suggest that tuning EMSIs is an effective way to achieve SACs with high activity and durability.
基金the funding support from the National Natural Science Foundation of China(Grants 22325903,22221003,and 22071225)the National Key Research and Development Program of China(Grant 2018YFA0702001)+1 种基金the Plan for Anhui Major Provincial Science&Technology Project(Grants 202203a0520013 and 2021d05050006)the USTC Research Funds of the Double First-Class Initiative(Grant YD2060002032).
文摘The high activity and stability of intermetallic PtCo nanocatalysts toward oxygen reduction reaction make them a top candidate as low-Pt cathode catalysts in proton exchange membrane fuel cells(PEMFCs).However,forming intermetallic structures typically requires high-temperature annealing,posing a challenge for achieving well-size control and highly ordered structures.Here we report the design and synthesis of bimetallic co re@shell structured precursors for affording high-performance intermetallic PtCo catalysts.The fabrication of the core@shell precursor involves using a molecular ligand containing both sulfur and oxygen donors to selectively bind with Pt colloidal nanoparticles as the core and chelate Co ions as the shell.During high-temperature annealing,the ligand transforms into carbon coatings around alloy nanoparticles,preventing particle sintering;meanwhile,Co ions in the shell can easily diffuse into the Pt core,which helps to increase the thermodynamic driving force for forming intermetallic structures.These benefits enable us to obtain the catalyst with finely dispersed nanoparticles(~3.5 nm)and a high ordering degree of 72%.With 0.1 mgPt/cm^(2)cathode loading,the catalyst delivers superior performance and durability in PEMFCs,showing an initial mass activity of 0.56 A/mgPt,an initial power density of 1.05 W/cm^(2)at 0.67 V(H_(2)-air),and a voltage loss of 26 mV at 0.8 A/cm^(2)after the accelerated durability test.
基金financially supported by the National Natural Science Foundation of China(Nos.92372122 and 52471242)the Fundamental Research Funds for the Central Universities,China(Nos.GG2060127001,KY2060000150,and WK2060000040)supported by the Joint Laboratory for USTC and Yanchang Petroleum,China(No.2022ZK-03)。
文摘Along with the surging demand for energy storage devices,the cost and availability of the materials remain dominant factors in slowing down their industrial application.The repurposing of waste asphalt into high-performance electrode materials is of significant interest,as it holds the potential to circumvent energy and environmental issues.Here,we report the controllable synthesis of asphalt-derived mesoporous carbon as an active material for electrocatalytic hydrogen gas capacitor(EHGC).The hierarchically porous carbon(HPC)with a high surface area of 1943.4 m^(2)·g^(-1)can operate in pH universal aqueous electrolytes in EHGC.It displays a specific energy and power density of 57 Wh·kg^(-1)and 554 W·kg^(-1)in neutral electrolyte as well as 52 Wh·kg^(-1)and 657 W·kg^(-1)in acidic electrolyte.Additionally,the charge storage mechanism of HPC-EHGC is studied with the help of Raman spectroscopy and X-ray photoelectron spectroscopy.Furthermore,the assembled HPC-EHGC device displays a discharge capacitance of 170 F·g^(-1)with an excellent capacitance retention rate of 100%up to 20000 cycles at 10 A·g^(-1)in acidic electrolyte.This work introduces a novel approach to converting waste asphalt into high-performance carbon for EHGC,achieving superior performance over commercial materials.By simultaneously addressing environmental waste issues and advancing energy storage technology,this study makes a significant contribution to sustainable materials science and next-generation battery development.
