The adsorptive denitrification performance of MIL-101(Cr)-0.5 toward pyridine,aniline or quinoline in simulated fuels with basic nitrogen content of 1732μg/g was evaluated separately.Furthermore,the effects of adsorp...The adsorptive denitrification performance of MIL-101(Cr)-0.5 toward pyridine,aniline or quinoline in simulated fuels with basic nitrogen content of 1732μg/g was evaluated separately.Furthermore,the effects of adsorption temperature,adsorption time and adsorbent dosage on their adsorptive denitrification performance were systematically investigated.The experimental results demonstrated that under a fixed adsorbent dosage of 0.05 g and a simulated fuel volume of 10 mL,the optimal removal efficiency for aniline was achieved at 30℃ within 30 min,whereas higher temperatures and longer times(40℃and 40 min)were required for effective removal of pyridine and quinoline.Density Functional Theory(DFT)calculations were conducted via Materials Studio(MS)software to study the adsorptive denitrification mechanism of MIL-101(Cr)toward these three basic nitrogen-containing compounds.The simulation calculation results revealed that the interaction between pyridine and MIL-101(Cr)primarily involved coordination adsorption.In contrast,the interaction between aniline or quinoline and MIL-101(Cr)proceeded mainly through coordination,with additional contributions fromπ-complexation and hydrogen bonding.The overall adsorption strength order is pyridine>aniline>quinoline.During the adsorption process,pyridine and quinoline transfer electrons to the MIL-101(Cr)surface through the H→C→N→Cr^(3+)pathway,while aniline transfers electrons to the MIL-101(Cr)surface through various pathways,including N→Cr^(3+),N→C→Cr^(3+)and N→H→O.Furthermore,adsorption kinetics studies indicated that the adsorption processes for all three basic nitrogen-containing compounds followed the quasi second order kinetic models.The experimental results on the effect of benzene on the adsorptive denitrification performance of MIL-101(Cr)-0.5 demonstrated that benzene exerted a more significant impact on the adsorption of aniline and quinoline.Finally,the adsorbent was regenerated using ethanol washing.It was found that MIL-101(Cr)-0.5 retained stable denitrification performance after two regeneration cycles.展开更多
The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor ...The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.展开更多
In molybdenum chemistry,the oxidative addition of o-quinone or 1,2-dicarbonyl compounds to molybdenum has been widely used in Mo-catalyzed C—C bond construction.The carbonyl oxidative addition to Mo(0)or Mo(Ⅱ)is the...In molybdenum chemistry,the oxidative addition of o-quinone or 1,2-dicarbonyl compounds to molybdenum has been widely used in Mo-catalyzed C—C bond construction.The carbonyl oxidative addition to Mo(0)or Mo(Ⅱ)is the critical elementary reaction of molybdenum catalysis.However,the relevant density functional theory(DFT)studies are relatively scarce,especially regarding the rational selection of functionals.In this work,14 functionals were employed to investigate the Mo-catalyzed carbonyl oxidative addition step.A benchmark study was carried out to evaluate their performance in structure optimization and energy calculation.Analyses of mean absolute error(MAE)and mean squared error(MSE)indicated that the B3LYP-D3(BJ),TPSSh,and ωB97X-D functionals exhibited superior performance in structure optimization.Using the DLPNO-CCSD(T)functional as the reference,the M06,M06-L,and MN15-L functionals exhibited good performance for energy calculation based on the structures optimized using the B3LYP-D3(BJ)functional.In particular,MN15-L provided the best performance with the smallest MAE and MSE.展开更多
A detailed investigation was carried out to understand how the variations in configurations of the spiroannulated 6-6-6-5-5 pentacyclic diastereoisomers,the key intermediates for the synthesis of two C30 terpene quino...A detailed investigation was carried out to understand how the variations in configurations of the spiroannulated 6-6-6-5-5 pentacyclic diastereoisomers,the key intermediates for the synthesis of two C30 terpene quinonemethides and their stereoisomers,impact the reactivity of cyclopropanation.The configurations at C9,C8,and C14 for all four pentacyclic diastereoisomers involved in the diastereoisomeric mixture were determined through a combination of suitable chemical derivatization and multiple NMR spectroscopic analyses.Based on the defined configuration,the 3D structures of these diastereoisomers were optimized by density functional theory(DFT)calculation.These investigations provide reasonable supports,mainly from the steric considerations,for understanding why different diastereoisomers exhibit markedly different reactivity,as well as regio-and stereo-selectivity for cyclopropanation.In addition,the mechanism for the construction of the spiroannulated 6-6-6-5-5 pentacyclic scaffold via intramolecular Michael/aldol cascade was also investigated by deuterium labeling experiments.展开更多
Under the context of global energy transition and carbon neutrality,controlling nitrogen oxide(NO_(x))emissions from biomass combustion is of great significance,and the development of high-efficiency low-temperature c...Under the context of global energy transition and carbon neutrality,controlling nitrogen oxide(NO_(x))emissions from biomass combustion is of great significance,and the development of high-efficiency low-temperature catalysts has become a current research focus.In this study,Nb was used to dope and modify the Mn_(7)-Cu_(3)/BCN catalyst to construct the Mn_(7)-Cu_(3)-Nb_(x)/BCN system.The doping amount was optimized through selective catalytic reduction(SCR)activity tests.The reaction mechanism was explored by combining in situ DRIFTS and density functional theory(DFT)simulations.Experimental findings revealed that the catalyst doped with 0.05%Nb achieved the optimal performance,sustaining a NO conversion efficiency of≥94%within the temperature window of 150−275℃while demonstrating improved resistance to alkali metal K poisoning.Mechanistic analyses showed that at low temperatures,the catalyst facilitated the SCR reaction via both the Eley-Rideal(E-R)and Langmuir-Hinshelwood(L-H)pathways,with the synergistic interaction between multiple active sites driving the efficient conversion of NH3 and NO.DFT calculations further confirmed that both pathways had the characteristics of low reaction energy barriers and significant exothermicity,ensuring the high activity and feasibility of the low-temperature reaction.The findings provided foundational theoretical support for the design of Nb-doped Mn-Cu-supported catalysts and the exploration of the underlying working mechanisms.展开更多
N,N,N',N'-tetraoctyl diglycolamide(TODGA)is a potential extractant for the co-extraction of lanthanides and actinides in high-level liquid waste.In this study,the radiolysis and extraction properties of TODGA ...N,N,N',N'-tetraoctyl diglycolamide(TODGA)is a potential extractant for the co-extraction of lanthanides and actinides in high-level liquid waste.In this study,the radiolysis and extraction properties of TODGA in kerosene solvents contacted with the aqueous phase of varying HNO_(3) concentrations were systematically investigated,and the complexation mechanism was analyzed in conjunction with density functional theory(DFT)calculations.After γ-irradiation,the variation of TODGA concentration was detected,and the variation trends in the relative content of radiolysis products(RPs)with sample type and absorbed dose were demonstrated.Results indicated that the breaking of the amide bond,ether bond,and C_(amide)-C_(ether)bond was the primary radiolysis routes.The aqueous-phase precipitate was studied as a potential new mode of TODGA radiolysis in ultrapure water aqueous phase.Moreover,TODGA/kerosene exhibited excellent extraction capabilities for lanthanides even after absorbing 100 kGy,and HNO_(3) can maintain a portion of TODGA's extraction capacity.The DFT method was applied to calculate and evaluate the complexing ability of TODGA and some of its RPs toward lanthanides.The results revealed that the complexing ability of TODGA for Ce(Ⅲ),Eu(Ⅲ),and Dy(Ⅲ)was enhanced successively,and the complexing ability of the RPs with intact oxygen-containing structures could not be neglected.展开更多
With the development of hydrate technology,more and more applications have been appeared in many areas.However,hydrate additive is always one research hotspot,it has attracted more and more attention.The influence of ...With the development of hydrate technology,more and more applications have been appeared in many areas.However,hydrate additive is always one research hotspot,it has attracted more and more attention.The influence of two biosurfactants on CO_(2) hydrate formation process were investigated.Through the investigation of experiment research,rhamnolipid and sophorolipid had the promotion effect on CO_(2) hydrate formation kinetics.Hydrate gas storage reached the maximum value 32.01(volume ratio)and conversion ratio of water to hydrate was 19.42%when sophorolipid concentration was 0.05%(mass).Hydrate gas storage capacity reached the maximum value 31.22(volume ratio)and conversion ratio of water to hydrate was 18.94%when rhamnolipid concentration was 0.05%(mass).Through the comparison of gas storage capacity and hydrate formation rate,sophorolipid had stronger promotion effect on CO_(2) hydrate formation kinetics than rhamnolipid.It increased the depth of gas hydration reaction.CO_(2) hydrate formation gas was carried out under the condition of constant temperature and volume.Hydration number was considered in the hydrate calculation process.Combined with hydrate formation kinetic theory of Chen–Guo model,the hydrated gas volume was compared with remaining volume of reactor.This model could calculate the change of CO_(2) hydrate gas storage capacity over time.The calculated values of gas storage was in good agreement with experimental values.So this study has the better guiding function for relevant hydrate technology application.展开更多
With the rapid growth of technologies requiring high-power energy storage,achieving long-term cyclic stability under ultra-high current density is a key challenge.Aqueous zinc-ion batteries(AZIBs)are promising candida...With the rapid growth of technologies requiring high-power energy storage,achieving long-term cyclic stability under ultra-high current density is a key challenge.Aqueous zinc-ion batteries(AZIBs)are promising candidates due to their intrinsic safety and low cost,but they suffer from severe interfacial instability at rates exceeding 10 mA cm^(-2),which drastically shortens their cycle life.Inspired by theoretical calculations,triglyme(TGDE)additive with strong electron-donating groups into Zn(OTf)_(2) electrolytes effectively disrupts the hydrogen-bond network among free water molecules,while the weak coordination of TGDE with Zn^(2+)promotes the entry of OTf-into the primary Zn^(2+)solvated sheath,thus decreasing the coordination number of water with Zn^(2+).As such,the hydrogen-bond network and the bulk solvated structure are reconstructed with better stability.Moreover,the strong adsorption of TGDE lying on the Zn(002)surface would induce Zn depositions along(002)together with the reduced exposed surface,further effectively inhibiting side reactions.Likewise,TGDE electrolyte induces the formation of such ZnF_(2)-ZnS dual-layer solid electrolyte interface(SEI)with superior chemical stability and ionic conductivity,thereby regulating Zn^(2+)flux with dendrite-free depositions.Based on this electrolyte,Zn‖Zn cells can be stably cycled for 1300 h at a limit of 10 mA cm^(-2) and 10 mAh cm^(-2).The assembled Zn‖V_(2)O_(5) full cells still maintain 99.9%capacity retention after 1000 cycles at 10 A g^(-1).This work provides a feasible approach for designing aqueous electrolytes to reconstruct the hydrogen-bond network and solvated structure,which can be extended to the applications of high-rate and high-temperature scenarios.展开更多
Four new sesquiterpenoids(1-4), including the first reported instance of a novel 2,3-seco oplopane carbon skeleton(1), together with 19 known analogues, were isolated from the flower buds of Tussilago farfara(coltsfoo...Four new sesquiterpenoids(1-4), including the first reported instance of a novel 2,3-seco oplopane carbon skeleton(1), together with 19 known analogues, were isolated from the flower buds of Tussilago farfara(coltsfoot). The challenging determination of relative and absolute configurations—particularly in flexible side chains and substituents—was achieved for the first time through an integrated approach combining spectroscopic analyses, chemical derivatization, chiral gas chromatography(GC), and quantum chemical calculations. All compounds were evaluated for anti-diabetic activity using an insulin-stimulated glucose uptake model in C2C12 myotubes and for anti-inflammatory activity via a lipopolysaccharide(LPS)-induced nitric oxide(NO) inhibition assay in RAW264.7 macrophages. Six compounds significantly enhanced glucose uptake, and mechanistic investigation of compound 3 revealed activation of the insulin receptor substrate 1(IRS-1)/protein kinase B(Akt)/glycogen synthase kinase 3β(GSK-3β) signaling pathway. Twenty-one compounds exhibited marked inhibition of NO production;among them, compounds 2 and 6 dose-dependently suppressed inducible nitric oxide synthase(iNOS) expression and nuclear factor κB(NF-κB) phosphorylation.展开更多
The hydrogen evolution reaction(HER) is a key process in electrocatalytic water splitting for hydrogen production,yet it is often limited by sluggish H^(*)-OH adsorption and H*binding kinetics.We obtained Rumodified N...The hydrogen evolution reaction(HER) is a key process in electrocatalytic water splitting for hydrogen production,yet it is often limited by sluggish H^(*)-OH adsorption and H*binding kinetics.We obtained Rumodified Ni O nanoparticles(Ru-Ni O/NF) with enhanced HER properties by substituting ruthenium(Ru)for Ni atoms in the Ni O(200) crystalline facets on nickel foam by a one-step electrodeposition technique.This novel catalyst exhibits a significantly reduced H^(*)-OH adsorption energy and improved kinetics,with an overpotential of only 60 mV at 10 mA/cm^(2) and a Tafel slope of 26.19 mV/dec.The Ru-Ni O/NF maintains its activity for over 115 h,outperforming NiO/NF by reducing the overpotential by 177 mV.DFT calculations confirm that the addition of Ru to NiO enhances the HER kinetics by modifying the electronic structure,optimizing the surface chemistry,stabilizing the intermediates,lowering the energy barriers,and facilitating efficient charge transfer through a robust three-dimensional structure,resulting in a change in the rate-limiting step and a significant reduction in the Gibbs free energy.This study presents a highly efficient HER catalyst and offers insights into designing advanced NiO-based electrocatalysts by reducing reaction energy barriers.展开更多
Hard carbon(HC)is a promising anode candidate for sodium-ion batteries(SIBs),yet its application is plagued by unstable interfaces and poor long-term cyclability.Herein,we develop a facile solvent evaporation strategy...Hard carbon(HC)is a promising anode candidate for sodium-ion batteries(SIBs),yet its application is plagued by unstable interfaces and poor long-term cyclability.Herein,we develop a facile solvent evaporation strategy to synthesize ultrathin Al_(2)O_(3)-coated biomass-derived HC(GSC-Al_(2)O_(3)-3%).The conformal Al_(2)O_(3)layer passivates defects and micropores,suppresses side reactions,and promotes the formation of a robust organic-inorganic hybrid solid electrolyte interphase.Comprehensive characterizations,including in situ X-ray diffraction,ex situ Raman spectra,X-ray photoelectron spectroscopy,time of flight secondary ion mass spectrometry,solid-state 27Al nuclear magnetic resonance,and atomic force microscope modulus mapping,demonstrate that Al_(2)O_(3)actively participates in SEI reconstruction,enhancing the chemical and mechanical stability.Electrochemical tests reveal that the optimized GSC-Al_(2)O_(3)-3%anode delivers 91%capacity retention after 1000 cycles at 1.0 A g^(-1),and possesses excellent wide-temperature tolerance(149.3 mAh g^(-1)at-30℃and 286.8 mAh g^(-1)at 60℃).Mechanistic studies confirm a synergistic Na+storage process involving"adsorption-intercalation-pore filling,"while density functional theory calculations and electrostatic potential mapping reveal that Al_(2)O_(3)coating regulates interfacial charge distribution and reduces Na+migration barriers.A full cell paired with a NaNi_(0.5)Fe_(0.5)MnO_(4)cathode exhibits a high initial capacity of 395.7 mAh g^(-1)and outstanding cycling stability(200 cycles).This work provides fundamental mechanistic insights into interfacial engineering of HC and establishes a cost-effective,scalable route for the next generation highperformance SIBs.展开更多
For loops with UV divergences,assuming that the physical contributions of loops from UV regions are insignificant,a UV-free scheme method described by an equation is introduced to derive loop results without UV diverg...For loops with UV divergences,assuming that the physical contributions of loops from UV regions are insignificant,a UV-free scheme method described by an equation is introduced to derive loop results without UV divergences in the calculations,i.e.,a route of the analytic continuation T_(F)→T_(P)besides the traditional route∞-∞in the mathematical structure.This scheme provides a new perspective to an open question of the hierarchy problem of Higgs mass,i.e.,an alternative interpretation without fine-tuning within the standard model.展开更多
Charge-transfer complexes(CTCs)have emerged as promising n-type organic thermoelectric(TE)materials due to their inherent high electrical conductivity and tunable transport polarities.In this study,we performed a comp...Charge-transfer complexes(CTCs)have emerged as promising n-type organic thermoelectric(TE)materials due to their inherent high electrical conductivity and tunable transport polarities.In this study,we performed a comprehensive first-principles investigation on the TE properties of nine CTCs comprised of 2,7-dialkyl[1]benzothieno[3,2-b][1]benzothiophenes(CnBTBT,n=4,8,12)as donors and fluorinated derivatives of tetracyanoquinodimethane(F_(m)TCNQ,m=0,2,4)as acceptors,aiming to identify high-performance n-type organic TE materials and elucidate the underlying structure-property relationships.Our calculation results,based on the Boltzmann transport equation and deformation potential theory,reveal that the length of the alkyl side chains and the number of fluorine substitutions significantly impact their electronic structures and TE properties.Notably,the CnBTBT-F_(m)TCNQ CTCs with shorter alkyl chains and more fluorine substitution demonstrate superior n-type characteristics,particularly C4BTBT-F4TCNQ,which achieves an excellent power factor of 671µW cm^(-1) K^(-2) at an optimal charge carrier concentration.Our findings not only clarify the critical role of molecular engineering in CTC-based TE materials but also provide valuable guidance for developing high-efficiency organic TE materials with versatile practical applications.展开更多
Oxygen evolution reaction(OER)is widely recognized as a bottleneck of water electrolysis.To determine the underlying reaction mechanisms,particularly the relative contribution of the adsorbate evolution mechanism(AEM)...Oxygen evolution reaction(OER)is widely recognized as a bottleneck of water electrolysis.To determine the underlying reaction mechanisms,particularly the relative contribution of the adsorbate evolution mechanism(AEM)and lattice-oxygen participation mechanism(LOM),we conduct a comprehensive investigation combining Density Functional Theory(DFT)calculations and experimental validation.Our theoretical analysis of doped RuO_(2)catalysts reveals that heteroatom doping(Ni,Cu,and Zn)induces significant local charge transfer,leading to the increased charge state of Ru and the downshifted d-band center.This,in turn,enables the mechanism switching from the conventional AEM to the more efficient LOM,and finally improves OER activity.We also establish a simple yet powerful descriptor,Ne of Ru(representing charge density of Ru sites),which enables accurate prediction of both catalytic activity and stability.Guided by these theoretical predictions,we successfully synthesize a Ni-doped RuO_(2)catalyst,which exhibits excellent OER activity and stability in acidic media,achieving an overpotential of just 156 mV and maintaining stability for 4000 h at 10 mA cm^(−2),significantly surpassing the performance of the commercial RuO_(2).These findings not only provide fundamental insights into the mechanism-switching behavior in OER catalysis but also offer a practical strategy for designing high-performance,stable electrocatalysts for acidic water electrolysis.展开更多
Excessive phosphorus and arsenic in water bodies not only destroy ecosystems but also pose a serious threat to human health.In this study,a series of Al-doped modified metal-organic frameworks(Zr-Al-MOF)were prepared ...Excessive phosphorus and arsenic in water bodies not only destroy ecosystems but also pose a serious threat to human health.In this study,a series of Al-doped modified metal-organic frameworks(Zr-Al-MOF)were prepared by solvothermal method,which achieved efficient removal of phosphate and arsenate in water.Due to the use of inexpensive Al salts,the material has a lower cost and is more economical.The molar ratio of metal salts,adsorption time,solution pH,initial concentration,temperature and coexisting anions were studied,and it was found that when the molar ratio of Zr:Al was 2,Zr-Al-MOF had the best adsorption performance for phosphate and arsenate,and the maximum adsorption capacity was 93.04 mg P/g and 173.83 mg As/g,respectively.It traps phosphate and arsenate at a fast reaction rate and can be recycled repeatedly.In addition,0.15 g/L of 2Zr-Al-MOF can effectively reduce the phosphate and arsenate content in the contaminated spring water samples of Yangzonghai Lake to the standard range of drinking water,which further confirms the application potential of 2Zr-Al-MOF.By FT-IR and XPS analysis,it was found that the adsorption mechanism was ligand exchange,electrostatic attraction and hydrogen bond formation.The theoretical calculation shows that the adsorption energy is negative,which indicates that 2Zr-Al-MOF is attractive to phosphate and arsenate,and the adsorption state is stable.The results show that 2Zr-Al-MOF is an effective phosphate and arsenate adsorbent and has broad application prospects in eutrophication water treatment.展开更多
Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is c...Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is crucial for the confirmation of absolute configurations.Ignoring critical parameters will lead to false structure,which may confuse the total synthesis and drug development.Herein,the configurations of seven heterogeneous Pallavicinia diterpenoids(PDs) isolated from Pallavicinia liverworts are revised using a combination of single-crystal X-ray diffraction and electronic circular dichroism(ECD) calculations.Meanwhile,identification of five unprecedented PD heterodimers PD-dimers A-E(18-22) along with eleven previously undescribed PDs(5-9,13-17,23) obtained by the reinvestigation of the Chinese liverwort Pallavicinia subciliata have resulted in corrections and support the revised conclusions.展开更多
MoTe_(2) has emerged as a promising candidate in the field of integrated circuits,memristive devices,and catalysts,owing to its polymorphic nature across different phases.Experimentally,strain engineering has been dem...MoTe_(2) has emerged as a promising candidate in the field of integrated circuits,memristive devices,and catalysts,owing to its polymorphic nature across different phases.Experimentally,strain engineering has been demonstrated as an effective approach for manipulating the phase transition of MoTe_(2),but the mechanism remains unclear.The strain-dependent phase transition and its micro-mechanisms have been investigated based on first principle calculations.As demonstrated,critical strain and phase transition path from H→T'phases are strongly governed by the applied strain's orientation,magnitude,and triaxiality.At the atomic level,nonzero movements of Te atoms within the phase transition domain with mechanical unloading have been clarified,together with an advanced understanding on the impact of strain on Te-vacancies migration.These insights advanced the knowledge of MoTe_(2) phase transition behavior and demonstrated the large space to explore potential applications through strain,defect,and phase engineering.展开更多
Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of a...Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of available material systems,making the identification of novel 2D multilayer kagome candidates particularly important.In this work,three types of 2D materials with trilayer kagome lattices,namely Sc_(6)S_(5)X_(6)(X=Cl,Br,I),are predicted based on first-principles calculations.These 2D materials feature two kagome lattices composed of Sc atoms and one kagome lattice composed of S atoms.Stability analysis indicates that these materials can exist as free-standing 2D materials.Electronic structure calculations reveal that Sc_(6)S_(5)X_(6)are narrow-bandgap semiconductors(0.76–0.95 e V),with their band structures exhibiting flat bands contributed by Sc-based kagome lattices and Dirac band gaps resulting from symmetry breaking.The sulfur-based kagome lattice in the central layer contributes an independent flat band below the Fermi level.Additionally,Sc_(6)S_(5)X_(6)exhibit high carrier mobility,with hole and electron mobilities reaching up to 10^(3)cm^(2)·V^(-1)·s^(-1),indicating potential applications in low-dimensional electronic devices.This work provides an excellent example for the development of novel multilayer 2D kagome materials.展开更多
Heat-induced emission peak shift(HIEPS),encompassing both redshift and blueshift,remains mechanistically unresolved in phosphor materials.Using state-of-the-art first-principles calculations of M_(2)SiO_(4):Eu^(2+)(M=...Heat-induced emission peak shift(HIEPS),encompassing both redshift and blueshift,remains mechanistically unresolved in phosphor materials.Using state-of-the-art first-principles calculations of M_(2)SiO_(4):Eu^(2+)(M=Sr,Ba,Ca),we reveal that conventional thermal expansion theory cannot adequately explain these phenomena.Instead,our frozen phonon analysis identifies local electron-phonon coupling as the dominant mechanism,where anisotropic thermal vibrations selectively distort the asymmetric Eu-5d potential well that arises from the dopant’s coordination environment.This distortion manifests through the temperature-sensitiveΔ_(f−d) parameter governing the 5d→4f transition energy,directly controlling spectral shifts.Our findings establish a universal framework for HIEPS in rare-earth phosphors and enable a Δ_(f−d)-guided strategy for designing thermally stable phosphors.展开更多
基金Supported by Basic Scientific Research Project of the Liaoning Provincial Department of Education Has Been Unveiled to Facilitate Local Project Funding (JYTMS20230835)Enhanced Scientific Research Project Funded by the Departmentof Higher Education in Liaoning Province (General program)(JYTMS20230852)。
文摘The adsorptive denitrification performance of MIL-101(Cr)-0.5 toward pyridine,aniline or quinoline in simulated fuels with basic nitrogen content of 1732μg/g was evaluated separately.Furthermore,the effects of adsorption temperature,adsorption time and adsorbent dosage on their adsorptive denitrification performance were systematically investigated.The experimental results demonstrated that under a fixed adsorbent dosage of 0.05 g and a simulated fuel volume of 10 mL,the optimal removal efficiency for aniline was achieved at 30℃ within 30 min,whereas higher temperatures and longer times(40℃and 40 min)were required for effective removal of pyridine and quinoline.Density Functional Theory(DFT)calculations were conducted via Materials Studio(MS)software to study the adsorptive denitrification mechanism of MIL-101(Cr)toward these three basic nitrogen-containing compounds.The simulation calculation results revealed that the interaction between pyridine and MIL-101(Cr)primarily involved coordination adsorption.In contrast,the interaction between aniline or quinoline and MIL-101(Cr)proceeded mainly through coordination,with additional contributions fromπ-complexation and hydrogen bonding.The overall adsorption strength order is pyridine>aniline>quinoline.During the adsorption process,pyridine and quinoline transfer electrons to the MIL-101(Cr)surface through the H→C→N→Cr^(3+)pathway,while aniline transfers electrons to the MIL-101(Cr)surface through various pathways,including N→Cr^(3+),N→C→Cr^(3+)and N→H→O.Furthermore,adsorption kinetics studies indicated that the adsorption processes for all three basic nitrogen-containing compounds followed the quasi second order kinetic models.The experimental results on the effect of benzene on the adsorptive denitrification performance of MIL-101(Cr)-0.5 demonstrated that benzene exerted a more significant impact on the adsorption of aniline and quinoline.Finally,the adsorbent was regenerated using ethanol washing.It was found that MIL-101(Cr)-0.5 retained stable denitrification performance after two regeneration cycles.
文摘The efficiency and stability of catalysts for photocatalytic hydrogen evolution(PHE)are largely governed by the charge transfer behaviors across the heterojunction interfaces.In this study,CuO,a typical semiconductor featuring a broad spectral absorption range,is successfully employed as the electron acceptor to combine with CdS for constructing a S-scheme heterojunction.The optimized photocatalyst(CdSCuO2∶1)delivers an exceptional hydrogen evolution rate of 18.89 mmol/(g·h),4.15-fold higher compared with bare CdS.X-ray photoelectron spectroscopy(XPS)and ultraviolet-visible diffuse reflection absorption spectroscopy(UV-vis DRS)confirmed the S-scheme band structure of the composites.Moreover,the surface photovoltage(SPV)and electron paramagnetic resonance(EPR)indicated that the photogenerated electrons and photogenerated holes of CdS-CuO2∶1 were respectively transferred to the conduction band(CB)of CdS with a higher reduction potential and the valence band(VB)of CuO with a higher oxidation potential under illumination,as expected for the S-scheme mechanism.Density-functional-theory calculations of the electron density difference(EDD)disclose an interfacial electric field oriented from CdS to CuO.This built-in field suppresses charge recombination and accelerates carrier migration,rationalizing the markedly enhanced PHE activity.This study offers a novel strategy for designing S-scheme heterojunctions with high light harvesting and charge utilization toward sustainable solar-tohydrogen conversion.
基金Project supported by the Fundamental Research Funds for the Central Universities(No.2042025kf0052)。
文摘In molybdenum chemistry,the oxidative addition of o-quinone or 1,2-dicarbonyl compounds to molybdenum has been widely used in Mo-catalyzed C—C bond construction.The carbonyl oxidative addition to Mo(0)or Mo(Ⅱ)is the critical elementary reaction of molybdenum catalysis.However,the relevant density functional theory(DFT)studies are relatively scarce,especially regarding the rational selection of functionals.In this work,14 functionals were employed to investigate the Mo-catalyzed carbonyl oxidative addition step.A benchmark study was carried out to evaluate their performance in structure optimization and energy calculation.Analyses of mean absolute error(MAE)and mean squared error(MSE)indicated that the B3LYP-D3(BJ),TPSSh,and ωB97X-D functionals exhibited superior performance in structure optimization.Using the DLPNO-CCSD(T)functional as the reference,the M06,M06-L,and MN15-L functionals exhibited good performance for energy calculation based on the structures optimized using the B3LYP-D3(BJ)functional.In particular,MN15-L provided the best performance with the smallest MAE and MSE.
文摘A detailed investigation was carried out to understand how the variations in configurations of the spiroannulated 6-6-6-5-5 pentacyclic diastereoisomers,the key intermediates for the synthesis of two C30 terpene quinonemethides and their stereoisomers,impact the reactivity of cyclopropanation.The configurations at C9,C8,and C14 for all four pentacyclic diastereoisomers involved in the diastereoisomeric mixture were determined through a combination of suitable chemical derivatization and multiple NMR spectroscopic analyses.Based on the defined configuration,the 3D structures of these diastereoisomers were optimized by density functional theory(DFT)calculation.These investigations provide reasonable supports,mainly from the steric considerations,for understanding why different diastereoisomers exhibit markedly different reactivity,as well as regio-and stereo-selectivity for cyclopropanation.In addition,the mechanism for the construction of the spiroannulated 6-6-6-5-5 pentacyclic scaffold via intramolecular Michael/aldol cascade was also investigated by deuterium labeling experiments.
基金Supported by National Key Research and Development Program of China(2020YFD1100302)。
文摘Under the context of global energy transition and carbon neutrality,controlling nitrogen oxide(NO_(x))emissions from biomass combustion is of great significance,and the development of high-efficiency low-temperature catalysts has become a current research focus.In this study,Nb was used to dope and modify the Mn_(7)-Cu_(3)/BCN catalyst to construct the Mn_(7)-Cu_(3)-Nb_(x)/BCN system.The doping amount was optimized through selective catalytic reduction(SCR)activity tests.The reaction mechanism was explored by combining in situ DRIFTS and density functional theory(DFT)simulations.Experimental findings revealed that the catalyst doped with 0.05%Nb achieved the optimal performance,sustaining a NO conversion efficiency of≥94%within the temperature window of 150−275℃while demonstrating improved resistance to alkali metal K poisoning.Mechanistic analyses showed that at low temperatures,the catalyst facilitated the SCR reaction via both the Eley-Rideal(E-R)and Langmuir-Hinshelwood(L-H)pathways,with the synergistic interaction between multiple active sites driving the efficient conversion of NH3 and NO.DFT calculations further confirmed that both pathways had the characteristics of low reaction energy barriers and significant exothermicity,ensuring the high activity and feasibility of the low-temperature reaction.The findings provided foundational theoretical support for the design of Nb-doped Mn-Cu-supported catalysts and the exploration of the underlying working mechanisms.
文摘N,N,N',N'-tetraoctyl diglycolamide(TODGA)is a potential extractant for the co-extraction of lanthanides and actinides in high-level liquid waste.In this study,the radiolysis and extraction properties of TODGA in kerosene solvents contacted with the aqueous phase of varying HNO_(3) concentrations were systematically investigated,and the complexation mechanism was analyzed in conjunction with density functional theory(DFT)calculations.After γ-irradiation,the variation of TODGA concentration was detected,and the variation trends in the relative content of radiolysis products(RPs)with sample type and absorbed dose were demonstrated.Results indicated that the breaking of the amide bond,ether bond,and C_(amide)-C_(ether)bond was the primary radiolysis routes.The aqueous-phase precipitate was studied as a potential new mode of TODGA radiolysis in ultrapure water aqueous phase.Moreover,TODGA/kerosene exhibited excellent extraction capabilities for lanthanides even after absorbing 100 kGy,and HNO_(3) can maintain a portion of TODGA's extraction capacity.The DFT method was applied to calculate and evaluate the complexing ability of TODGA and some of its RPs toward lanthanides.The results revealed that the complexing ability of TODGA for Ce(Ⅲ),Eu(Ⅲ),and Dy(Ⅲ)was enhanced successively,and the complexing ability of the RPs with intact oxygen-containing structures could not be neglected.
基金supported by the Science Foundation of Zhejiang Pharmaceutical University Science Foundation of XIAO2024006General project of Education Department of Zhejiang Province(2024116/Y202456535)Fenghua District Science and Technology Association Natural Science Foundation Project 05,which were greatly acknowledged.
文摘With the development of hydrate technology,more and more applications have been appeared in many areas.However,hydrate additive is always one research hotspot,it has attracted more and more attention.The influence of two biosurfactants on CO_(2) hydrate formation process were investigated.Through the investigation of experiment research,rhamnolipid and sophorolipid had the promotion effect on CO_(2) hydrate formation kinetics.Hydrate gas storage reached the maximum value 32.01(volume ratio)and conversion ratio of water to hydrate was 19.42%when sophorolipid concentration was 0.05%(mass).Hydrate gas storage capacity reached the maximum value 31.22(volume ratio)and conversion ratio of water to hydrate was 18.94%when rhamnolipid concentration was 0.05%(mass).Through the comparison of gas storage capacity and hydrate formation rate,sophorolipid had stronger promotion effect on CO_(2) hydrate formation kinetics than rhamnolipid.It increased the depth of gas hydration reaction.CO_(2) hydrate formation gas was carried out under the condition of constant temperature and volume.Hydration number was considered in the hydrate calculation process.Combined with hydrate formation kinetic theory of Chen–Guo model,the hydrated gas volume was compared with remaining volume of reactor.This model could calculate the change of CO_(2) hydrate gas storage capacity over time.The calculated values of gas storage was in good agreement with experimental values.So this study has the better guiding function for relevant hydrate technology application.
基金the financial support provided by the National Natural Science Foundation of China(grant no.22373032)the open research fund of Songshan Lake Materials Laboratory(grant no.2023SLABFK06)。
文摘With the rapid growth of technologies requiring high-power energy storage,achieving long-term cyclic stability under ultra-high current density is a key challenge.Aqueous zinc-ion batteries(AZIBs)are promising candidates due to their intrinsic safety and low cost,but they suffer from severe interfacial instability at rates exceeding 10 mA cm^(-2),which drastically shortens their cycle life.Inspired by theoretical calculations,triglyme(TGDE)additive with strong electron-donating groups into Zn(OTf)_(2) electrolytes effectively disrupts the hydrogen-bond network among free water molecules,while the weak coordination of TGDE with Zn^(2+)promotes the entry of OTf-into the primary Zn^(2+)solvated sheath,thus decreasing the coordination number of water with Zn^(2+).As such,the hydrogen-bond network and the bulk solvated structure are reconstructed with better stability.Moreover,the strong adsorption of TGDE lying on the Zn(002)surface would induce Zn depositions along(002)together with the reduced exposed surface,further effectively inhibiting side reactions.Likewise,TGDE electrolyte induces the formation of such ZnF_(2)-ZnS dual-layer solid electrolyte interface(SEI)with superior chemical stability and ionic conductivity,thereby regulating Zn^(2+)flux with dendrite-free depositions.Based on this electrolyte,Zn‖Zn cells can be stably cycled for 1300 h at a limit of 10 mA cm^(-2) and 10 mAh cm^(-2).The assembled Zn‖V_(2)O_(5) full cells still maintain 99.9%capacity retention after 1000 cycles at 10 A g^(-1).This work provides a feasible approach for designing aqueous electrolytes to reconstruct the hydrogen-bond network and solvated structure,which can be extended to the applications of high-rate and high-temperature scenarios.
基金supported by the National Natural Science Foundation of China (No. 22077111)the Department of Education of Guangdong Province (No. 2022ZDJS025)+1 种基金the Hong Kong/Macao Joint Research and Development Fund Project of Wuyi University (No. 2022WGALH15)Zhejiang Medical and Health Science and Technology Plan Project of China (No.2022KY231)。
文摘Four new sesquiterpenoids(1-4), including the first reported instance of a novel 2,3-seco oplopane carbon skeleton(1), together with 19 known analogues, were isolated from the flower buds of Tussilago farfara(coltsfoot). The challenging determination of relative and absolute configurations—particularly in flexible side chains and substituents—was achieved for the first time through an integrated approach combining spectroscopic analyses, chemical derivatization, chiral gas chromatography(GC), and quantum chemical calculations. All compounds were evaluated for anti-diabetic activity using an insulin-stimulated glucose uptake model in C2C12 myotubes and for anti-inflammatory activity via a lipopolysaccharide(LPS)-induced nitric oxide(NO) inhibition assay in RAW264.7 macrophages. Six compounds significantly enhanced glucose uptake, and mechanistic investigation of compound 3 revealed activation of the insulin receptor substrate 1(IRS-1)/protein kinase B(Akt)/glycogen synthase kinase 3β(GSK-3β) signaling pathway. Twenty-one compounds exhibited marked inhibition of NO production;among them, compounds 2 and 6 dose-dependently suppressed inducible nitric oxide synthase(iNOS) expression and nuclear factor κB(NF-κB) phosphorylation.
基金supported by the National Natural Science Foundation of China (No.22275052)Department of Science and Technology of Hubei Province (Nos.2025AFA111 and 2024CSA076)。
文摘The hydrogen evolution reaction(HER) is a key process in electrocatalytic water splitting for hydrogen production,yet it is often limited by sluggish H^(*)-OH adsorption and H*binding kinetics.We obtained Rumodified Ni O nanoparticles(Ru-Ni O/NF) with enhanced HER properties by substituting ruthenium(Ru)for Ni atoms in the Ni O(200) crystalline facets on nickel foam by a one-step electrodeposition technique.This novel catalyst exhibits a significantly reduced H^(*)-OH adsorption energy and improved kinetics,with an overpotential of only 60 mV at 10 mA/cm^(2) and a Tafel slope of 26.19 mV/dec.The Ru-Ni O/NF maintains its activity for over 115 h,outperforming NiO/NF by reducing the overpotential by 177 mV.DFT calculations confirm that the addition of Ru to NiO enhances the HER kinetics by modifying the electronic structure,optimizing the surface chemistry,stabilizing the intermediates,lowering the energy barriers,and facilitating efficient charge transfer through a robust three-dimensional structure,resulting in a change in the rate-limiting step and a significant reduction in the Gibbs free energy.This study presents a highly efficient HER catalyst and offers insights into designing advanced NiO-based electrocatalysts by reducing reaction energy barriers.
基金supported by National Natural Science Foundation,China(Nos.52261135632,U21A20284)Natural Science Foundation of Henan,China(No.232300421080)+3 种基金Program for Innovative Team(in Science and Technology)in University of Henan Province,China(No.24IRTSTHN006)Henan Distinguished Foreign Scientists Workgroup in Electrochemical Energy Storage,China(No.GZS2015013)Key Scientific Research Programs in Universities of Henan Province,China-Special Projects for Basic Research(No.23ZX008)Cultivation Project of Tuoxin Team in Henan University of Technology,China(No.2024TXTD11)。
文摘Hard carbon(HC)is a promising anode candidate for sodium-ion batteries(SIBs),yet its application is plagued by unstable interfaces and poor long-term cyclability.Herein,we develop a facile solvent evaporation strategy to synthesize ultrathin Al_(2)O_(3)-coated biomass-derived HC(GSC-Al_(2)O_(3)-3%).The conformal Al_(2)O_(3)layer passivates defects and micropores,suppresses side reactions,and promotes the formation of a robust organic-inorganic hybrid solid electrolyte interphase.Comprehensive characterizations,including in situ X-ray diffraction,ex situ Raman spectra,X-ray photoelectron spectroscopy,time of flight secondary ion mass spectrometry,solid-state 27Al nuclear magnetic resonance,and atomic force microscope modulus mapping,demonstrate that Al_(2)O_(3)actively participates in SEI reconstruction,enhancing the chemical and mechanical stability.Electrochemical tests reveal that the optimized GSC-Al_(2)O_(3)-3%anode delivers 91%capacity retention after 1000 cycles at 1.0 A g^(-1),and possesses excellent wide-temperature tolerance(149.3 mAh g^(-1)at-30℃and 286.8 mAh g^(-1)at 60℃).Mechanistic studies confirm a synergistic Na+storage process involving"adsorption-intercalation-pore filling,"while density functional theory calculations and electrostatic potential mapping reveal that Al_(2)O_(3)coating regulates interfacial charge distribution and reduces Na+migration barriers.A full cell paired with a NaNi_(0.5)Fe_(0.5)MnO_(4)cathode exhibits a high initial capacity of 395.7 mAh g^(-1)and outstanding cycling stability(200 cycles).This work provides fundamental mechanistic insights into interfacial engineering of HC and establishes a cost-effective,scalable route for the next generation highperformance SIBs.
基金supported by the open project of the theoretical physics academic exchange platform of Chongqing University。
文摘For loops with UV divergences,assuming that the physical contributions of loops from UV regions are insignificant,a UV-free scheme method described by an equation is introduced to derive loop results without UV divergences in the calculations,i.e.,a route of the analytic continuation T_(F)→T_(P)besides the traditional route∞-∞in the mathematical structure.This scheme provides a new perspective to an open question of the hierarchy problem of Higgs mass,i.e.,an alternative interpretation without fine-tuning within the standard model.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Science(No.XDB0520000)the National Natural Science Foundation of China(Nos.52273170 and 52394271)the National Key R&D Program of China(No.2022YFA1203200).
文摘Charge-transfer complexes(CTCs)have emerged as promising n-type organic thermoelectric(TE)materials due to their inherent high electrical conductivity and tunable transport polarities.In this study,we performed a comprehensive first-principles investigation on the TE properties of nine CTCs comprised of 2,7-dialkyl[1]benzothieno[3,2-b][1]benzothiophenes(CnBTBT,n=4,8,12)as donors and fluorinated derivatives of tetracyanoquinodimethane(F_(m)TCNQ,m=0,2,4)as acceptors,aiming to identify high-performance n-type organic TE materials and elucidate the underlying structure-property relationships.Our calculation results,based on the Boltzmann transport equation and deformation potential theory,reveal that the length of the alkyl side chains and the number of fluorine substitutions significantly impact their electronic structures and TE properties.Notably,the CnBTBT-F_(m)TCNQ CTCs with shorter alkyl chains and more fluorine substitution demonstrate superior n-type characteristics,particularly C4BTBT-F4TCNQ,which achieves an excellent power factor of 671µW cm^(-1) K^(-2) at an optimal charge carrier concentration.Our findings not only clarify the critical role of molecular engineering in CTC-based TE materials but also provide valuable guidance for developing high-efficiency organic TE materials with versatile practical applications.
基金supported by the National Natural Science Foundation of China(22472104)Guangdong Basic and Applied Basic Research Foundation(2024A1515012075,2024A1515010028)the Postdoctoral Fellowship Program of CPS Funder(GZC20241083,2025M771117)。
文摘Oxygen evolution reaction(OER)is widely recognized as a bottleneck of water electrolysis.To determine the underlying reaction mechanisms,particularly the relative contribution of the adsorbate evolution mechanism(AEM)and lattice-oxygen participation mechanism(LOM),we conduct a comprehensive investigation combining Density Functional Theory(DFT)calculations and experimental validation.Our theoretical analysis of doped RuO_(2)catalysts reveals that heteroatom doping(Ni,Cu,and Zn)induces significant local charge transfer,leading to the increased charge state of Ru and the downshifted d-band center.This,in turn,enables the mechanism switching from the conventional AEM to the more efficient LOM,and finally improves OER activity.We also establish a simple yet powerful descriptor,Ne of Ru(representing charge density of Ru sites),which enables accurate prediction of both catalytic activity and stability.Guided by these theoretical predictions,we successfully synthesize a Ni-doped RuO_(2)catalyst,which exhibits excellent OER activity and stability in acidic media,achieving an overpotential of just 156 mV and maintaining stability for 4000 h at 10 mA cm^(−2),significantly surpassing the performance of the commercial RuO_(2).These findings not only provide fundamental insights into the mechanism-switching behavior in OER catalysis but also offer a practical strategy for designing high-performance,stable electrocatalysts for acidic water electrolysis.
基金supported by the NSFC-Yunnan Joint Fund(No.U2102210)the National Natural Science Foundation of China(No.22168044)+1 种基金Yunnan Provincial Department of Science and Technology(No.202201BF070001-013)the Research Innovation Fund for Graduate Students of Yunnan University(No.KC-23234004).
文摘Excessive phosphorus and arsenic in water bodies not only destroy ecosystems but also pose a serious threat to human health.In this study,a series of Al-doped modified metal-organic frameworks(Zr-Al-MOF)were prepared by solvothermal method,which achieved efficient removal of phosphate and arsenate in water.Due to the use of inexpensive Al salts,the material has a lower cost and is more economical.The molar ratio of metal salts,adsorption time,solution pH,initial concentration,temperature and coexisting anions were studied,and it was found that when the molar ratio of Zr:Al was 2,Zr-Al-MOF had the best adsorption performance for phosphate and arsenate,and the maximum adsorption capacity was 93.04 mg P/g and 173.83 mg As/g,respectively.It traps phosphate and arsenate at a fast reaction rate and can be recycled repeatedly.In addition,0.15 g/L of 2Zr-Al-MOF can effectively reduce the phosphate and arsenate content in the contaminated spring water samples of Yangzonghai Lake to the standard range of drinking water,which further confirms the application potential of 2Zr-Al-MOF.By FT-IR and XPS analysis,it was found that the adsorption mechanism was ligand exchange,electrostatic attraction and hydrogen bond formation.The theoretical calculation shows that the adsorption energy is negative,which indicates that 2Zr-Al-MOF is attractive to phosphate and arsenate,and the adsorption state is stable.The results show that 2Zr-Al-MOF is an effective phosphate and arsenate adsorbent and has broad application prospects in eutrophication water treatment.
基金supported by the National Natural Science Foundation of China (Nos.82293682,82293684,and 82173703)。
文摘Owing to their intricate molecular frameworks and copious chiral centers,the structural identification and configurational assignment of natural products are challenging tasks.Comprehensive spectral data analysis is crucial for the confirmation of absolute configurations.Ignoring critical parameters will lead to false structure,which may confuse the total synthesis and drug development.Herein,the configurations of seven heterogeneous Pallavicinia diterpenoids(PDs) isolated from Pallavicinia liverworts are revised using a combination of single-crystal X-ray diffraction and electronic circular dichroism(ECD) calculations.Meanwhile,identification of five unprecedented PD heterodimers PD-dimers A-E(18-22) along with eleven previously undescribed PDs(5-9,13-17,23) obtained by the reinvestigation of the Chinese liverwort Pallavicinia subciliata have resulted in corrections and support the revised conclusions.
基金supported by NSFC Grants(Nos.12032004,11872114,and 11502150)Natural Science Foundation of Hebei Province of China(No.A2016210060)+1 种基金The Higher Education Youth Talents Program of Hebei Province of China(No.BJ2017052)Science and Technology Project of Hebei Education Department(No.QN2020204)。
文摘MoTe_(2) has emerged as a promising candidate in the field of integrated circuits,memristive devices,and catalysts,owing to its polymorphic nature across different phases.Experimentally,strain engineering has been demonstrated as an effective approach for manipulating the phase transition of MoTe_(2),but the mechanism remains unclear.The strain-dependent phase transition and its micro-mechanisms have been investigated based on first principle calculations.As demonstrated,critical strain and phase transition path from H→T'phases are strongly governed by the applied strain's orientation,magnitude,and triaxiality.At the atomic level,nonzero movements of Te atoms within the phase transition domain with mechanical unloading have been clarified,together with an advanced understanding on the impact of strain on Te-vacancies migration.These insights advanced the knowledge of MoTe_(2) phase transition behavior and demonstrated the large space to explore potential applications through strain,defect,and phase engineering.
基金supported by the Fundamental Research Funds for the Central Universities(WUT:2024IVA052 and Grant No.104972025KFYjc0089)。
文摘Two-dimensional(2D)multilayer kagome materials hold significant research value for regulating kagome-related physical properties and exploring quantum effects.However,their development is hindered by the scarcity of available material systems,making the identification of novel 2D multilayer kagome candidates particularly important.In this work,three types of 2D materials with trilayer kagome lattices,namely Sc_(6)S_(5)X_(6)(X=Cl,Br,I),are predicted based on first-principles calculations.These 2D materials feature two kagome lattices composed of Sc atoms and one kagome lattice composed of S atoms.Stability analysis indicates that these materials can exist as free-standing 2D materials.Electronic structure calculations reveal that Sc_(6)S_(5)X_(6)are narrow-bandgap semiconductors(0.76–0.95 e V),with their band structures exhibiting flat bands contributed by Sc-based kagome lattices and Dirac band gaps resulting from symmetry breaking.The sulfur-based kagome lattice in the central layer contributes an independent flat band below the Fermi level.Additionally,Sc_(6)S_(5)X_(6)exhibit high carrier mobility,with hole and electron mobilities reaching up to 10^(3)cm^(2)·V^(-1)·s^(-1),indicating potential applications in low-dimensional electronic devices.This work provides an excellent example for the development of novel multilayer 2D kagome materials.
基金supported by the National Natural Science Foundation(NSF)of China(62475265,22031009,22075282,12404064)the National Key Research and Development Program of China(2021YFB3601501)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB1170000)NSF of Fujian Province(2023J01212,2024J08106).
文摘Heat-induced emission peak shift(HIEPS),encompassing both redshift and blueshift,remains mechanistically unresolved in phosphor materials.Using state-of-the-art first-principles calculations of M_(2)SiO_(4):Eu^(2+)(M=Sr,Ba,Ca),we reveal that conventional thermal expansion theory cannot adequately explain these phenomena.Instead,our frozen phonon analysis identifies local electron-phonon coupling as the dominant mechanism,where anisotropic thermal vibrations selectively distort the asymmetric Eu-5d potential well that arises from the dopant’s coordination environment.This distortion manifests through the temperature-sensitiveΔ_(f−d) parameter governing the 5d→4f transition energy,directly controlling spectral shifts.Our findings establish a universal framework for HIEPS in rare-earth phosphors and enable a Δ_(f−d)-guided strategy for designing thermally stable phosphors.
