Intrinsic two-dimensional(2D)ferromagnetic(FM)semiconductors have attracted extensive attentions for their potential applications in next-generation spintronics devices.In recent years,the van der Waals material VI_(3...Intrinsic two-dimensional(2D)ferromagnetic(FM)semiconductors have attracted extensive attentions for their potential applications in next-generation spintronics devices.In recent years,the van der Waals material VI_(3) has been experimentally found to be an intrinsic FM semiconductor.However,the electronic structure of the VI_(3) is not fully understood.To reveal why the VI_(3)is a ferromagnetic semiconductor with strong out-of-plane anisotropy,we systematically studied the electronic structure of the monolayer VI_(3).Our results confirm that the monolayer VI_(3) is a Mott insulator,and d^(2) electrons occupy a_(g) and e_(g)^(π+) orbitals.The half-metallic state is a metastable state with a total energy 0.7 e V higher than the ferromagnetic Mott insulating state.Furthermore,our study confirmed that the VI_(3)exhibits the out-of-plane magnetic anisotropy,which originates from d^(2) electrons occupying low-lying agand egπ+orbitals.Since the orbital angular momentum of the e_(g)^(π+) state is not completely quenched,the VI_(3) has the out-of-plane anisotropy under interplay between the spin-orbit coupling and crystal field.Our study provides valuable guidance for the design of 2D magnetic materials with pronounced out-of-plane anisotropy.展开更多
Surface adsorption plays a crucial role in various natural and industrial processes,particularly in the field of energy storage.The adsorption of sodium atoms on 2D layered materials can significantly impact their per...Surface adsorption plays a crucial role in various natural and industrial processes,particularly in the field of energy storage.The adsorption of sodium atoms on 2D layered materials can significantly impact their performance as carriers and electrodes in ion batteries.While it is commonly acknowledged that pristine graphene is not favorable for sodium ion adsorption,the suitability of other 2D materials with similar honeycomb symmetry remains unclear.In this study,we employ systematic first-principles calculations to explore interlayer interactions and electron transfer effects on sodium adsorption on 2D van der Waals(vdW)heterostructures(HTSs)surfaces.Our results demonstrate that sodium adsorption is energetically favorable on these substrates.Moreover,we find that the adsorption strength can be effectively tuned by manipulation of the electron accumulation or depletion of the layer directly interacting with the sodium atom.By stacking these layered materials with different electron abundancy to form vd W HTSs,the charge density of the substrate becomes tunable through interlayer charge transfer.In these vdW HTSs,the adsorption behavior of sodium is primarily controlled by the absorption layer and exhibits a linear correlation with its pz-band center.Additionally,we identify linear correlations between the sodium adsorption energies,the electron loss of the sodium atom,the interlayer charge transfer,and the heights of the adsorbed sodium atom.These discoveries underscore the impact of interlayer electron transfer and interactions on sodium ion adsorption on 2D vd W HTSs and providing new insights into material design for alkali atom adsorption.展开更多
Exploring electrode materials with a high volumetric energy density and high rate capability remains of a great challenge for nanosized-Li_(4)Ti_(5)O_(12)(LTO)batteries.Here,hierarchical porous Ti^(3+)-C-N-Br co-doped...Exploring electrode materials with a high volumetric energy density and high rate capability remains of a great challenge for nanosized-Li_(4)Ti_(5)O_(12)(LTO)batteries.Here,hierarchical porous Ti^(3+)-C-N-Br co-doped LTO(LTOCPB-CC)is synthesized using carboxyl-grafted nanocarbon(CC)and cetylpyridinium bromide(CPB)as combined structure-directing agents.Ti^(4+)-O-CPB/Li^(+)-CC is designed as a new molecular chelate,in which CPB and CC promote the uniform mixing of Li^(+)and Ti^(4+)and control the morphology of TiO_(2) and the final product.The defects(oxygen vacancies and ion dopants)formed during the annealing process increase the electron/hole concentration and reduce the band gap,both of which enhance the n-type electron modification of LTO.As-prepared LTOCPB-CC has a large specific surface area and high tap density,as well as a high electronic conductivity(2.84×10^(-4) S cm^(-1))and ionic conductivity(3.82×10^(-12)cm^(2) s^(-1)),which are responsible for its excellent rate capability(157.7 mA h g^(-1) at 20 C)and stable long-term cycling performance(0.008% fade per cycle after 1000 cycles at 20 C).展开更多
Ammonia(NH_(3))is one of the most important building blocks of the chemical industry and a promising sustainable energy carrier.Conventional production of NH_(3)via the Haber-Bosch process requires high temperature an...Ammonia(NH_(3))is one of the most important building blocks of the chemical industry and a promising sustainable energy carrier.Conventional production of NH_(3)via the Haber-Bosch process requires high temperature and high pressure,which is energy demanding and suffers safety issues.Photocatalytic nitrogen reduction reaction(NRR)is a green and sustainable route for NH_(3) production,and has been expected to be an alternative for NH_(3)production under mild conditions.However,solar-driven N_(2)activated has appeared as the bottleneck for photocatalytic NRR.In this work,we propose that single Ru atom supported by BeO monolayer is a promising photocatalytic single atom catalyst(SAC)for efficient N_(2)activation with visible illumination.The high efficiency originates from the enhanced absorption in the visible range,as well as the back-donation mechanism when N_(2)were adsorbed on the SAC.Our results show that N_(2)can be efficiently activated by the Ru/BeO SAC and be reduced to NH_(3) with extremely low limiting potential of-0.41 V.The NRR process also exhibits dominate selectivity respect to hydrogen evolution.展开更多
Photocatalytic water splitting utilizing solar energy is considered as one of the most ideal strategies for solving the ene rgy and environmental issues.Recently,two-dimensional(2 D)materials with an intrinsic dipole ...Photocatalytic water splitting utilizing solar energy is considered as one of the most ideal strategies for solving the ene rgy and environmental issues.Recently,two-dimensional(2 D)materials with an intrinsic dipole show great chance to achieve excellent photocatalytic performance.In this work,blue-phase monolayer carbon monochalcogenides(CX,X=S,Se)are constructed and systematically studied as photocatalysts for water splitting by performing first-principles calculations based on density functional theory.After confirming the great dynamical,thermal,and mechanical stability of CX monolayers,we observe that they possess moderate band gaps(2.41 eV for CS and 2.46 eV for CSe)and high carrier mobility(3.23×10^(4)cm^(2)V^(^(-1))s^(-1)for CS and 4.27×10^(3)cm^(2)V^(-1)s^(-1)for CSe),comparable to those of many recently reported 2 D photocatalysts.Moreover,these two monolayer materials are found to have large intrinsic dipole(0.43 D for CS and 0.51 D for CSe),thus the build-in internal electric field can be selfintroduced,which can effectively drive the separation of photongenerated carriers.More importantly,the well-aligned band edge as well as rather pronounced optical absorption in the visible-light and ultraviolet regions further ensure that our proposed CX monolayers can be used as high efficient photocatalysts for water splitting.Additionally,the effects of external strain on the electronic,optical and photocatalytic properties of CX monolayers are also evaluated.These theoretical predictions will stimulate further work to open up the energy-related applications of CX monolayers.展开更多
Electrocatalytic nitrogen reduction reaction(NRR)is an environmentally friendly method for sustainable ammonia synthesis under ambient conditions.Searching for efficient NRR electrocatalysts with high activity and sel...Electrocatalytic nitrogen reduction reaction(NRR)is an environmentally friendly method for sustainable ammonia synthesis under ambient conditions.Searching for efficient NRR electrocatalysts with high activity and selectivity is currently urgent but remains great challenge.Herein,we systematically investigate the NRR catalytic activities of single and double transition metal atoms(TM=Fe,Co,Ni and Mo)anchored on g-C_(6)N_(6) monolayers by performing first-principles calculation.Based on the stability,activity,and selectivity analysis,Mo_(2)@g-C_(6)N_(6) monolayer is screened out as the most promising candidate for NRR.Further exploration of the reaction mechanism demonstrates that the Mo dimer anchored on g-C_(6)N_(6) can sufficiently activate and efficiently reduce the inert nitrogen molecule to ammonia through a preferred distal pathway with a particularly low limiting potential of -0.06 V.In addition,we find that Mo_(2)@g-C_(6)N_(6) has excellent NRR selectivity over the competing hydrogen evolution reaction,with the Faradaic efficiency being 100%.Our work not only predicts a kind of ideal NRR electrocatalyst but also encouraging more experimental and theoretical efforts to develop novel double-atom catalysts(DACs)for NRR.展开更多
CO_(2) capture is considered as one of the most ideal strategies for solving the environmental issues and against global warming.Recently,experimental evidence has suggested that aluminum double bond(dialumene) specie...CO_(2) capture is considered as one of the most ideal strategies for solving the environmental issues and against global warming.Recently,experimental evidence has suggested that aluminum double bond(dialumene) species can capture CO_(2) and further convert it into value-added products.However,the catalytic application of these species is still in its infancy.Both the dynamics mechanism of CO_(2) fixation and the detailed structures of catalytic intermediates are not well understood.In this work,we investigate the structure dependent resonance Raman(RR) signals for different reaction intermediates.Ab-initio simulations of spontaneous resonance Raman(spRR) and time-domain stimulated resonance Raman(stRR) give spectral signatures correlated to the existence of different intermediates during the CO_(2)-dialumene binding process.The unique Raman vibronic feature s contain rich structural information with high temporal resolution,enabling to monitor the transient catalytic intermediates under reaction conditions.Our work shows that RR can be used to monitor intermediates during the dialumene based CO_(2) capture reaction.The spectral features not only provide insight into the structural information of intermediate species,but also allow a deeper understanding of the dynamical details of this kind of catalytic process.展开更多
Base pair mismatch has been regarded as the main source of DNA point mutations, where minor shortlived tautomers were usually involved. However, the detection and characterization of these unnatural species pose chall...Base pair mismatch has been regarded as the main source of DNA point mutations, where minor shortlived tautomers were usually involved. However, the detection and characterization of these unnatural species pose challenges to existing techniques. Here, by using systematic structural and ultrafast resonance Raman(RR) spectral analysis for the four possible conformers of guanine-cytosine base pairs, the prominent marker Raman bands were identified. We found that the hydrogen bonding vibrational region from 2300 cm^(-1) to 3700 cm^(-1) is ideal for the identification of these short live species. The marker bands provide direct evidence for the existence of the tautomer species, thus offering an effective strategy to detect the short-lived minor species. Ultrafast resonance Raman spectroscopy would be a powerful tool to provide direct evidence of critical dynamical details of complex systems involving protonation or tautomerization.展开更多
Two-dimensional(2 D)materials with honeycomb,kagome or star lattice have been intensively studied because electrons in such lattices could give rise to exotic quantum effects.In order to improve structural diversity o...Two-dimensional(2 D)materials with honeycomb,kagome or star lattice have been intensively studied because electrons in such lattices could give rise to exotic quantum effects.In order to improve structural diversity of 2 D materials to achieve unique properties,here we propose a new quasi-2 D honeycombstar-honeycomb(HSH)lattice based on first-principles calculations.A carbon allotrope named HSH-C_(10) is designed with the HSH lattice,and its mechanical properties have been intensively investigated through total energy,phonon dispersion,ab initio molecular dynamic simulations,as well as elastic constants calculations.Besides the classical covalent bonds,there is an interesting charge-shift bond in this material from the chemical bonding analysis.Additionally,through the analysis of electronic structure,HSH-C_(10) is predicted to be a semiconductor with a direct band gap of 2.89 e V,which could combine the desirable characteristics of honeycomb and star lattice.Importantly,by modulating coupling strength,a flat band near the Fermi level can be obtained in compounds HSH-C_(6)Si_(4) and HSH-C_(6)Ge_(4),which have potential applications in superconductivity.Insight into such mixed lattice would inspire new materials with properties we have yet to imagine.展开更多
With increasing demand for renewable energy,graphene-like BC_(3) monolayer as high performance electrode materials for lithium and sodium batteries are drawing more attention recently.However,its structural stability,...With increasing demand for renewable energy,graphene-like BC_(3) monolayer as high performance electrode materials for lithium and sodium batteries are drawing more attention recently.However,its structural stability,potassium storage properties and strain effect on adsorption properties of alkali metal ions have not been reported yet.In this work,phonon spectra,AIMD simulations and elastic constants of graphene-like BC_(3) monolayer are investigated.Our results show that graphene-like BC_(3) monolayer possesses excellent structural stability and the maximum theoretical potassium storage capacity can reach up to 1653 mAh/g with the corresponding open circuit voltages 0.66 V.Due to potassium atom can be effectively adsorbed at the most energetically favorable h-CC site with obvious charge transfer,making adsorbed graphene-like BC_(3) monolayer change from semiconductor to metal which is really good for electrode utilization.Moreover,the migrations potassium atom on the graphene-like BC_(3) monolayer is rather fast with the diffusion barriers as low as 0.12 eV,comparing lithium atom with a relatively large diffusion barrier of 0.46 eV.Additionally,the tensile strains applied on the graphene-like BC3 monolayer have marginal effect on the adsorption and diffusion performances of lithium,sodium and potassium atoms.展开更多
Electrochemical CO reduction(ECOR)as a potential strategy for producing valuable chemicals and fuels has captured substantial attention.However,the currently available electrocatalysts suffer from poor selectivity and...Electrochemical CO reduction(ECOR)as a potential strategy for producing valuable chemicals and fuels has captured substantial attention.However,the currently available electrocatalysts suffer from poor selectivity and low Faradaic efficiency,limiting their industrial application.Herein,we systematically investigate the potential of homonuclear bimetallic electrocatalysts,Tm_(2)@C_(9)N_(4)(TM=Fe,Co,Ni,and Cu),for the ECOR through extensive density functional theory calculations.Our findings suggest that all four proposed monolayers exhibit exceptional stability,making them highly suitable for experimental synthesis and practical applications.Interestingly,these transition-metal dual atoms anchored on C_(9)N_(4)monolayers show great potential in facilitating the production of high-value C_(2)products,such as C_(2)H_(5)OH and C_(2)H_(4),due to the significantly low limiting potentials(-0.06~-0.46 V)and small kinetic energy barriers(0.54–1.08 eV)for the CO coupling process.Moreover,with the exception of Ni_(2)@C_(9)N_(4),these bimetallic catalysts demonstrate the impressive suppression of the competitive hydrogen evolution reaction(HER),leading to a high selectivity for C_(2)products in ECOR.Our predictions would accelerate the development of high-performance C_(9)N_(4)-based dual-atom catalysts for the ECOR.展开更多
Phononic crystals(PnCs)have had a multiple of important and promising applications such as sonic diodes,acoustic cloaking,optomechanic,and thermoelectrics[1–5].Undoubtably,it is of significance to explore new finding...Phononic crystals(PnCs)have had a multiple of important and promising applications such as sonic diodes,acoustic cloaking,optomechanic,and thermoelectrics[1–5].Undoubtably,it is of significance to explore new findings for PnCs,which can open new application opportunities.展开更多
基金partially supported by the Natural Science Foundation of Hubei Province(No.2022CFC030)the Science and Technology Research Project of Hubei Provincial Department of Education(No.D20212603)+2 种基金Hubei University of Arts and Science(No.2020kypytd002)the support from National Natural Science Foundation of China(No.22303098)the support from Anhui Provincial Natural Science Foundation(No.1908085MA10)。
文摘Intrinsic two-dimensional(2D)ferromagnetic(FM)semiconductors have attracted extensive attentions for their potential applications in next-generation spintronics devices.In recent years,the van der Waals material VI_(3) has been experimentally found to be an intrinsic FM semiconductor.However,the electronic structure of the VI_(3) is not fully understood.To reveal why the VI_(3)is a ferromagnetic semiconductor with strong out-of-plane anisotropy,we systematically studied the electronic structure of the monolayer VI_(3).Our results confirm that the monolayer VI_(3) is a Mott insulator,and d^(2) electrons occupy a_(g) and e_(g)^(π+) orbitals.The half-metallic state is a metastable state with a total energy 0.7 e V higher than the ferromagnetic Mott insulating state.Furthermore,our study confirmed that the VI_(3)exhibits the out-of-plane magnetic anisotropy,which originates from d^(2) electrons occupying low-lying agand egπ+orbitals.Since the orbital angular momentum of the e_(g)^(π+) state is not completely quenched,the VI_(3) has the out-of-plane anisotropy under interplay between the spin-orbit coupling and crystal field.Our study provides valuable guidance for the design of 2D magnetic materials with pronounced out-of-plane anisotropy.
基金the financial support by the National Key Research and Development Program of China(No.2019YFA0708700)the National Natural Science Foundation of China(Nos.62305196,U23B2087 and 62375158)+4 种基金the China Postdoctoral Science Foundation(No.GZC20231498)the Qingdao Postdoctoral Innovation Project(No.QDBSH20240102078)the Postdoctoral Innovation Program of Shandong Province(No.SDCX-ZG-202400318)Science and Technology Research Project of Hubei Provincial Department of Education(No.D20212603)Hubei University of Arts and Science(No.2020kypytd002)。
文摘Surface adsorption plays a crucial role in various natural and industrial processes,particularly in the field of energy storage.The adsorption of sodium atoms on 2D layered materials can significantly impact their performance as carriers and electrodes in ion batteries.While it is commonly acknowledged that pristine graphene is not favorable for sodium ion adsorption,the suitability of other 2D materials with similar honeycomb symmetry remains unclear.In this study,we employ systematic first-principles calculations to explore interlayer interactions and electron transfer effects on sodium adsorption on 2D van der Waals(vdW)heterostructures(HTSs)surfaces.Our results demonstrate that sodium adsorption is energetically favorable on these substrates.Moreover,we find that the adsorption strength can be effectively tuned by manipulation of the electron accumulation or depletion of the layer directly interacting with the sodium atom.By stacking these layered materials with different electron abundancy to form vd W HTSs,the charge density of the substrate becomes tunable through interlayer charge transfer.In these vdW HTSs,the adsorption behavior of sodium is primarily controlled by the absorption layer and exhibits a linear correlation with its pz-band center.Additionally,we identify linear correlations between the sodium adsorption energies,the electron loss of the sodium atom,the interlayer charge transfer,and the heights of the adsorbed sodium atom.These discoveries underscore the impact of interlayer electron transfer and interactions on sodium ion adsorption on 2D vd W HTSs and providing new insights into material design for alkali atom adsorption.
基金financially supported by the High-level Innovative Talents Training Project of Guizhou Province(QKHPTRC[2016]5658)the Guizhou Province Graduate Research Fund(YJSCXJH[2018]050)the Guizhou Province Graduate Research Fund(YJSCXJH[2018]081)。
文摘Exploring electrode materials with a high volumetric energy density and high rate capability remains of a great challenge for nanosized-Li_(4)Ti_(5)O_(12)(LTO)batteries.Here,hierarchical porous Ti^(3+)-C-N-Br co-doped LTO(LTOCPB-CC)is synthesized using carboxyl-grafted nanocarbon(CC)and cetylpyridinium bromide(CPB)as combined structure-directing agents.Ti^(4+)-O-CPB/Li^(+)-CC is designed as a new molecular chelate,in which CPB and CC promote the uniform mixing of Li^(+)and Ti^(4+)and control the morphology of TiO_(2) and the final product.The defects(oxygen vacancies and ion dopants)formed during the annealing process increase the electron/hole concentration and reduce the band gap,both of which enhance the n-type electron modification of LTO.As-prepared LTOCPB-CC has a large specific surface area and high tap density,as well as a high electronic conductivity(2.84×10^(-4) S cm^(-1))and ionic conductivity(3.82×10^(-12)cm^(2) s^(-1)),which are responsible for its excellent rate capability(157.7 mA h g^(-1) at 20 C)and stable long-term cycling performance(0.008% fade per cycle after 1000 cycles at 20 C).
基金the financial support from the National Natural Science Foundation of China(NSFC,Nos.21773309,21776315)the Fundamental Research Funds for the Central Universities(Nos.19CX05001A,20CX05010A)+1 种基金Hubei University of Arts and Science(Nos.2020kypytd002,2020kypytd003)Xiangyang Science and Technology Research and Development(No.2020YL09)。
文摘Ammonia(NH_(3))is one of the most important building blocks of the chemical industry and a promising sustainable energy carrier.Conventional production of NH_(3)via the Haber-Bosch process requires high temperature and high pressure,which is energy demanding and suffers safety issues.Photocatalytic nitrogen reduction reaction(NRR)is a green and sustainable route for NH_(3) production,and has been expected to be an alternative for NH_(3)production under mild conditions.However,solar-driven N_(2)activated has appeared as the bottleneck for photocatalytic NRR.In this work,we propose that single Ru atom supported by BeO monolayer is a promising photocatalytic single atom catalyst(SAC)for efficient N_(2)activation with visible illumination.The high efficiency originates from the enhanced absorption in the visible range,as well as the back-donation mechanism when N_(2)were adsorbed on the SAC.Our results show that N_(2)can be efficiently activated by the Ru/BeO SAC and be reduced to NH_(3) with extremely low limiting potential of-0.41 V.The NRR process also exhibits dominate selectivity respect to hydrogen evolution.
基金supported by the National Natural Science Foundation of China(No.21503149)the Program for Innovative Research Team in University of Tianjin(No.TD13-5074)the Project of Hubei University of Arts and Science(Nos.xk2020043,xk2020044,2020kypyfy015)。
文摘Photocatalytic water splitting utilizing solar energy is considered as one of the most ideal strategies for solving the ene rgy and environmental issues.Recently,two-dimensional(2 D)materials with an intrinsic dipole show great chance to achieve excellent photocatalytic performance.In this work,blue-phase monolayer carbon monochalcogenides(CX,X=S,Se)are constructed and systematically studied as photocatalysts for water splitting by performing first-principles calculations based on density functional theory.After confirming the great dynamical,thermal,and mechanical stability of CX monolayers,we observe that they possess moderate band gaps(2.41 eV for CS and 2.46 eV for CSe)and high carrier mobility(3.23×10^(4)cm^(2)V^(^(-1))s^(-1)for CS and 4.27×10^(3)cm^(2)V^(-1)s^(-1)for CSe),comparable to those of many recently reported 2 D photocatalysts.Moreover,these two monolayer materials are found to have large intrinsic dipole(0.43 D for CS and 0.51 D for CSe),thus the build-in internal electric field can be selfintroduced,which can effectively drive the separation of photongenerated carriers.More importantly,the well-aligned band edge as well as rather pronounced optical absorption in the visible-light and ultraviolet regions further ensure that our proposed CX monolayers can be used as high efficient photocatalysts for water splitting.Additionally,the effects of external strain on the electronic,optical and photocatalytic properties of CX monolayers are also evaluated.These theoretical predictions will stimulate further work to open up the energy-related applications of CX monolayers.
基金supported by the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(No.2020KJ008)the Natural Science Foundation of Tianjin(No.18JCQNJC76000)+3 种基金the College Students'Innovation and Entrepreneurship Training Program of Tianjin(No.202110065112)Science and Technology Research Project of Hubei Provincial De-partment of Education(No.D20212603)Hubei University of Arts and Science(Nos.2020kypytd002,XK2021024)China Scholarship Council.
文摘Electrocatalytic nitrogen reduction reaction(NRR)is an environmentally friendly method for sustainable ammonia synthesis under ambient conditions.Searching for efficient NRR electrocatalysts with high activity and selectivity is currently urgent but remains great challenge.Herein,we systematically investigate the NRR catalytic activities of single and double transition metal atoms(TM=Fe,Co,Ni and Mo)anchored on g-C_(6)N_(6) monolayers by performing first-principles calculation.Based on the stability,activity,and selectivity analysis,Mo_(2)@g-C_(6)N_(6) monolayer is screened out as the most promising candidate for NRR.Further exploration of the reaction mechanism demonstrates that the Mo dimer anchored on g-C_(6)N_(6) can sufficiently activate and efficiently reduce the inert nitrogen molecule to ammonia through a preferred distal pathway with a particularly low limiting potential of -0.06 V.In addition,we find that Mo_(2)@g-C_(6)N_(6) has excellent NRR selectivity over the competing hydrogen evolution reaction,with the Faradaic efficiency being 100%.Our work not only predicts a kind of ideal NRR electrocatalyst but also encouraging more experimental and theoretical efforts to develop novel double-atom catalysts(DACs)for NRR.
基金financial support from the National Natural Science Foundation of China (NSFC,No.21773309)Highlevel Science Foundation of Qingdao Agricultural University (No.663/1114351)+2 种基金the Fundamental Research Funds for the Central Universities (No.19CX05001A)Hubei University of Arts and Science (No.2020kypytd002)Xiangyang Science and Technology Research and Development (No.2020YL09)。
文摘CO_(2) capture is considered as one of the most ideal strategies for solving the environmental issues and against global warming.Recently,experimental evidence has suggested that aluminum double bond(dialumene) species can capture CO_(2) and further convert it into value-added products.However,the catalytic application of these species is still in its infancy.Both the dynamics mechanism of CO_(2) fixation and the detailed structures of catalytic intermediates are not well understood.In this work,we investigate the structure dependent resonance Raman(RR) signals for different reaction intermediates.Ab-initio simulations of spontaneous resonance Raman(spRR) and time-domain stimulated resonance Raman(stRR) give spectral signatures correlated to the existence of different intermediates during the CO_(2)-dialumene binding process.The unique Raman vibronic feature s contain rich structural information with high temporal resolution,enabling to monitor the transient catalytic intermediates under reaction conditions.Our work shows that RR can be used to monitor intermediates during the dialumene based CO_(2) capture reaction.The spectral features not only provide insight into the structural information of intermediate species,but also allow a deeper understanding of the dynamical details of this kind of catalytic process.
基金the financial support from the National Key Research and Development Program of China(No.2019YFA0708703)the National Natural Science Foundation of China(NSFC,No.21773309)+3 种基金the High-level Science Foundation of Qingdao Agricultural University(No.663/1114351)the Hefei National Laboratory for Physical Sciences at the Microscale(No.KF2020004)Xiangyang Science and Technology Research and Development(No.2020YL09)Hubei University of Arts and Science(Nos.HLOM222003,2020kypytd002)。
文摘Base pair mismatch has been regarded as the main source of DNA point mutations, where minor shortlived tautomers were usually involved. However, the detection and characterization of these unnatural species pose challenges to existing techniques. Here, by using systematic structural and ultrafast resonance Raman(RR) spectral analysis for the four possible conformers of guanine-cytosine base pairs, the prominent marker Raman bands were identified. We found that the hydrogen bonding vibrational region from 2300 cm^(-1) to 3700 cm^(-1) is ideal for the identification of these short live species. The marker bands provide direct evidence for the existence of the tautomer species, thus offering an effective strategy to detect the short-lived minor species. Ultrafast resonance Raman spectroscopy would be a powerful tool to provide direct evidence of critical dynamical details of complex systems involving protonation or tautomerization.
基金partially supported by the National Natural Science Foundation of China(Nos.21773124,12134019)by the Fundamental Research Funds for the Central Universities(Nankai University,No.63213042)+3 种基金by the Ph.D.Candidate Research Innovation Fund of Nankai UniversityScience and Technology Research Project of Hubei Provincial Department of Education(No.D20212603)Hubei University of Arts and Science(Nos.2020kypytd001,2020kypytd002,XK2021024)supported by the Supercomputing Center of Nankai University(NKSC)。
文摘Two-dimensional(2 D)materials with honeycomb,kagome or star lattice have been intensively studied because electrons in such lattices could give rise to exotic quantum effects.In order to improve structural diversity of 2 D materials to achieve unique properties,here we propose a new quasi-2 D honeycombstar-honeycomb(HSH)lattice based on first-principles calculations.A carbon allotrope named HSH-C_(10) is designed with the HSH lattice,and its mechanical properties have been intensively investigated through total energy,phonon dispersion,ab initio molecular dynamic simulations,as well as elastic constants calculations.Besides the classical covalent bonds,there is an interesting charge-shift bond in this material from the chemical bonding analysis.Additionally,through the analysis of electronic structure,HSH-C_(10) is predicted to be a semiconductor with a direct band gap of 2.89 e V,which could combine the desirable characteristics of honeycomb and star lattice.Importantly,by modulating coupling strength,a flat band near the Fermi level can be obtained in compounds HSH-C_(6)Si_(4) and HSH-C_(6)Ge_(4),which have potential applications in superconductivity.Insight into such mixed lattice would inspire new materials with properties we have yet to imagine.
基金partially supported by the National Natural Science Foundation of China (No.21503149)by the Program for Innovative Research Team in University of Tianjin (No.TD13-5074)+1 种基金by the Project of Hubei University of Arts and Science (No. 2020kypyfy015)Hubei Superior and Distinctive Discipline Group of "Mechatronics and Automobiles" (No.XKQ2020021)。
文摘With increasing demand for renewable energy,graphene-like BC_(3) monolayer as high performance electrode materials for lithium and sodium batteries are drawing more attention recently.However,its structural stability,potassium storage properties and strain effect on adsorption properties of alkali metal ions have not been reported yet.In this work,phonon spectra,AIMD simulations and elastic constants of graphene-like BC_(3) monolayer are investigated.Our results show that graphene-like BC_(3) monolayer possesses excellent structural stability and the maximum theoretical potassium storage capacity can reach up to 1653 mAh/g with the corresponding open circuit voltages 0.66 V.Due to potassium atom can be effectively adsorbed at the most energetically favorable h-CC site with obvious charge transfer,making adsorbed graphene-like BC_(3) monolayer change from semiconductor to metal which is really good for electrode utilization.Moreover,the migrations potassium atom on the graphene-like BC_(3) monolayer is rather fast with the diffusion barriers as low as 0.12 eV,comparing lithium atom with a relatively large diffusion barrier of 0.46 eV.Additionally,the tensile strains applied on the graphene-like BC3 monolayer have marginal effect on the adsorption and diffusion performances of lithium,sodium and potassium atoms.
基金supported by the Science and Technology Research Project of Hubei Provincial Department of Education(No.D20212603)Hubei University of Arts and Science(No.2020kypytd002)+1 种基金National Natural Science Foundation of China(No.22303098)Natural Science Foundation of Hubei Province(No.2022CFC030)。
文摘Electrochemical CO reduction(ECOR)as a potential strategy for producing valuable chemicals and fuels has captured substantial attention.However,the currently available electrocatalysts suffer from poor selectivity and low Faradaic efficiency,limiting their industrial application.Herein,we systematically investigate the potential of homonuclear bimetallic electrocatalysts,Tm_(2)@C_(9)N_(4)(TM=Fe,Co,Ni,and Cu),for the ECOR through extensive density functional theory calculations.Our findings suggest that all four proposed monolayers exhibit exceptional stability,making them highly suitable for experimental synthesis and practical applications.Interestingly,these transition-metal dual atoms anchored on C_(9)N_(4)monolayers show great potential in facilitating the production of high-value C_(2)products,such as C_(2)H_(5)OH and C_(2)H_(4),due to the significantly low limiting potentials(-0.06~-0.46 V)and small kinetic energy barriers(0.54–1.08 eV)for the CO coupling process.Moreover,with the exception of Ni_(2)@C_(9)N_(4),these bimetallic catalysts demonstrate the impressive suppression of the competitive hydrogen evolution reaction(HER),leading to a high selectivity for C_(2)products in ECOR.Our predictions would accelerate the development of high-performance C_(9)N_(4)-based dual-atom catalysts for the ECOR.
文摘Phononic crystals(PnCs)have had a multiple of important and promising applications such as sonic diodes,acoustic cloaking,optomechanic,and thermoelectrics[1–5].Undoubtably,it is of significance to explore new findings for PnCs,which can open new application opportunities.
