Heterogeneous solid frustrated-Lewis-pair(FLP)catalyst is of great promise in practical hydrogenation applications.It has been found that all-solid FLPs can be created on ceria via surface oxygen vacancy regulation.Co...Heterogeneous solid frustrated-Lewis-pair(FLP)catalyst is of great promise in practical hydrogenation applications.It has been found that all-solid FLPs can be created on ceria via surface oxygen vacancy regulation.Consequently,it is desired to investigate the mechanisms of the FLP-catalyzed hydrogenation of C=C and C=O and provide insight into the modification of CeO_(2)catalysts for the selective hydrogenation.In this work,the reaction mechanism of the hydrogenation of CH_(2)=CH_(2)and CH_(3)CH=O at the FLP sites constructed on CeO_(2)(110)surface was investigated by density functional theory(DFT),with the classical Lewis acid-base pairs(CLP)site as the reference.The results illustrate that at the CLP site,the dissociated hydride(H^(δ−))forms a stable H−O bond with the surface O atom,while at the FLP site,H^(δ−)is stabilized by Ce,displaying higher activity on the one hand.On the other hand,the electron cloud density of the Ce atom at the FLP site is higher,which can transfer more electrons to the adsorbed C_(C=C)and O_(C=O)atoms,leading to a higher degree of activation for C=C and C=O bonds,as indicated by the Bader charge analysis.Therefore,compared to the CLP site,the FLP site exhibits higher hydrogenation activity for CH_(2)=CH_(2)and CH_(3)CH=O.Furthermore,at the FLP sites,it demonstrates high efficiency in catalyzing the hydrogenation of CH_(2)=CH_(2)with the rate-determining barrier of 1.04 eV,but it shows limited activity for the hydrogenation of CH_(3)CH=O with the rate-determining barrier of 1.94 eV.It means that the selective hydrogenation of C=C can be effectively achieved at the FLP sites concerning selective hydrogenation catalysis.The insights shown in this work help to clarify the reaction mechanism of the hydrogenation of C=C and C=O at FLP site on CeO_(2)(110)and reveal the relationship between the catalytic performance and the nature of the active site,which is of great benefit to development of rational design of heterogeneous FLP catalysts.展开更多
The development of solid frustrated Lewis pairs(FLPs)catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention.Leveraging the divers...The development of solid frustrated Lewis pairs(FLPs)catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention.Leveraging the diverse oxidation states and structural tunability of cerium-based metal-organic frameworks(Ce-MOFs),this study employed a competitive coordination strategy utilizing a single carboxylate functional group ligand to construct a series of MOF-808-X(X=-NH_(2),-OH,-Br,and-NO_(2))featuring rich solid-state FLPs for hydrogenation of unsaturated olefins.The-X functional group serves as a microenvironment,enhancing hydrogenation activity by modulating the electronic properties and acid-base characteristics of the FLP sites.The unique redox properties of elemental cerium facilitate the exposure of unsaturated Ce sites(Ce-CUS,Lewis acid(LA))and adjacent Ce-OH(Lewis base(LB))sites within the MOFs,generating abundant solid-state FLP(Ce-CUS/Ce-OH)sites.Experimental results demonstrate that Ce-CUS and Ce-OH interact with theσandσ^(*)orbitals of H-H,and this"push-pull"synergy promotes heterolytic cleavage of the H-H bond.The lone pair electrons of the electron-donating functional group are transmitted through the molecular backbone to the LB site,thereby increasing its strength and reducing the activation energy required for H_(2)heterolytic cleavage.Notably,at 100℃and 2 MPa H_(2),MOF-808-NH_(2)achieves complete conversion of styrene and dicyclopentadiene,significantly outperforming MOF-808.Based on in-situ analysis and density functional theory calculations,a plausible reaction mechanism is proposed.This research enriches the theoretical framework for unsaturated olefin hydrogenation catalysts and contributes to the development of efficient catalytic systems.展开更多
Long-cycling dendrite-free solid-state lithium metal batteries (LMBs) require fast and uniform lithium-ion (Liþ)transport of solid-state electrolytes (SSEs). However, the SSEs still face the problems of low ionic...Long-cycling dendrite-free solid-state lithium metal batteries (LMBs) require fast and uniform lithium-ion (Liþ)transport of solid-state electrolytes (SSEs). However, the SSEs still face the problems of low ionic conductivity, lowLiþ transference number, and unstable interface with lithium metal. In this work, a novel strategy of frustratedLewis pairs (FLPs) modulating solid polymer electrolytes (SPEs) has been firstly proposed that enables durable Lireversible cycling. The tunable strength of Lewis acid and base dual-active sites of nickel borate FLPs can syn-ergisticallypromote both the dissociation of lithium salts and the transfer of Liþ. As a consequence, the FLPsmodulated SPEs (SPE-NiBO-150) exhibit high ionic conductivity of 4.92×10^(-4)S cm^(-1), high Liþ transferencenumber of 0.74, and superior interface compatibility with both lithium anode and LiFePO4 cathode at room-temperature.The Li//SPE-NiBO-150//Li symmetric cell demonstrates ultralong cycle stability (over 10,000 h(417 days) at both current density of 0.2 and 0.5 mA cm〓〓2), and the assembled solid-state LiFePO4//SPE-NiBO-150//Libattery also shows excellent performance (86% capacity retention for 300 cycles at 0.5C). The presentwork supplies a new insight into designing high-performance SPEs for solid-state LMB applications.展开更多
Catalytic reduction of 4-nitrophenol(4-NP)pollutant to the high-value 4-aminophenol(4-AP)with a clean hydrogen donor holds significant importance yet great challenges owing to the difficult activation of nitro and H s...Catalytic reduction of 4-nitrophenol(4-NP)pollutant to the high-value 4-aminophenol(4-AP)with a clean hydrogen donor holds significant importance yet great challenges owing to the difficult activation of nitro and H species.In this work,Ag tailoring Frustrated Lewis pairs(FLPs)of CeO_(2)(Ag/CeO_(2))were successfully fabricated for electrochemical reduction reaction of 4-NP(4-NP ERR).As a result,the bond of Ag with O atom changed the state of the Ce-O bond and electron density,where the tailored FLPs were the key factor for enhancing absorption and activation.The reaction rate of Ag/CeO_(2)reached up to 4.70 mmol·min^(-1)(Faraday efficiency:99.5%),which was about four times of CeO_(2).Additionally,this study delved into the proton-coupled electron processes to further understand the mechanism of 4-NP ERR.Therefore,in this study,we have endeavored to investigate the role of tailored FLPs sites and utilize this structure-function relationship to achieve environmentalfriendly chemical synthesis.展开更多
The alkaline hydrogen evolution reaction(HER)is a crucial process for sustainable hydrogen production,yet it requires efficient and stable electrocatalysts to overcome the high activation energy barrier.The article di...The alkaline hydrogen evolution reaction(HER)is a crucial process for sustainable hydrogen production,yet it requires efficient and stable electrocatalysts to overcome the high activation energy barrier.The article discusses a novel strategy for enhancing the performance of Ni-Fe layered double hydroxide(Ni-Fe LDH)in the alkaline HER by modifying it with a frustrated Lewis acid-base pair(FLP)constructed through vacancy engineering.The study found that the modified Ni-Fe LDH exhibited improved alkaline HER performance.Density functional theory(DFT)calculations demonstrate that the introduction of FLP can activate water and protons more efficiently than monometallic sites,thus reducing the alkaline HER energy barrier and overpotential.In HER under alkaline conditions,the Volmer step involves an additional hydrolysis dissociation compared to acidic conditions,which is one of the factors contributing to the slow reaction kinetics.This paper demonstrates that FLPs can alter the rate-determining step in alkaline HER from the Volmer step to a step with a lower energy barrier,more suitable for hydrogen desorption.The work provides new insights into the role of FLPs in regulating the mechanism and kinetics of HER and opens a new direction for the design and optimization of LDH-based and other electrocatalysts.展开更多
The construction of frustrated Lewis acid-base pairs(FLPs)in porous systems is very important for the field of industrial hydrogenation catalysis,but there is still a great challenge.Based on the Ce^(3+)/Ce^(4+)redox ...The construction of frustrated Lewis acid-base pairs(FLPs)in porous systems is very important for the field of industrial hydrogenation catalysis,but there is still a great challenge.Based on the Ce^(3+)/Ce^(4+)redox pairs and abundant defects in porous Ce-based metal-organic frameworks(Ce-MOFs),FLP sites consisting of ligand-defective Ce sites(Lewis acid,LA)and neighboring terminal O sites(Lewis base,LB)were constructed in situ by a simple vacuum thermal activation method in lamellar Ce-UiO-66-F.Defects/oxygen vacancies in the Ce-MOFs structure result in the difference in the electron cloud density between Ce and O,which is suitable for H-H hetero-cleavage and H-transfer in the dicyclopentadiene(DCPD)hydrogenation process.Particularly,Ce-UiO-66-F-200 achieved 96.9%conversion of DCPD and 97.8%selectivity of 8,9-dihydrodicyclopentadiene(8,9-DHDCPD)at 100℃ under 2MPa H2 for 10 h,which is 9.4 times higher than 10.2%conversion of DCPD over the unactivated Ce-UiO-66-F.This research promotes the understanding of solid MOFs-based porous FLPs for H_(2) activation,and encourages the in-depth investigation of surface solid FLPs to the whole material FLPs.展开更多
We extend a semiclassical numerical method, bosonic auxiliary-field Monte Carlo, to quantum spin systems. This method breaks the lattice into clusters, solves each cluster precisely and couples them with classical aux...We extend a semiclassical numerical method, bosonic auxiliary-field Monte Carlo, to quantum spin systems. This method breaks the lattice into clusters, solves each cluster precisely and couples them with classical auxiliary fields through classical Monte Carlo simulation. We test the method with antiferromagnetic spin models in one-dimensional chains, square lattices and triangular lattices, and obtain reasonable results at finite temperatures. This algorithm builds a bridge between classical Monte Carlo method and quantum methods. The algorithm can be improved with either progress in classical Monte Carlo sampling or the development of quantum solvers, and can also be further applied to systems with different lattices or interactions.展开更多
Density order is usually a consequence of the competition between long-range and short-range interactions.Here we report a density ordered superfluid emergent from a homogeneous Mott insulator due to the competition b...Density order is usually a consequence of the competition between long-range and short-range interactions.Here we report a density ordered superfluid emergent from a homogeneous Mott insulator due to the competition between frustrations and local interactions.This transition is found in a Bose–Hubbard model on a frustrated triangle lattice with an extra pairing term.Furthermore,we find a quantum phase transition between two different density ordered superfluids,which is beyond the Landau–Ginzburg(LG)paradigm.A U(1)symmetry is emergent at the critical point,while the symmetry in each density ordered superfluid is Z_(2)×Z_(3).We call the transition a‘shamrock transition’,due to its degenerate ground state in the parameter space being a shamrock-like curve rather than a circle in an LG-type transition.Effective low energy theories are established for the two transitions mentioned above and we find their resemblance and differences with clock models.展开更多
frustrated Lewis pair(FLP)是一个最近出现的新名词,指分子内或混合体系中同时具有路易斯酸和路易斯碱两个位点,由于空间位阻较大而使得这两个位点不能结合形成路易斯酸碱加合物,从而具有独特的反应活性。建议译为"受阻路易斯酸碱...frustrated Lewis pair(FLP)是一个最近出现的新名词,指分子内或混合体系中同时具有路易斯酸和路易斯碱两个位点,由于空间位阻较大而使得这两个位点不能结合形成路易斯酸碱加合物,从而具有独特的反应活性。建议译为"受阻路易斯酸碱对"。展开更多
Carboxylation of aromatics by CO2 to generate corresponding carboxylic acids is recently providing a novel approach to utilize the green gas CO2, in which the activation of CO2 is the key procedure. Among the many cat...Carboxylation of aromatics by CO2 to generate corresponding carboxylic acids is recently providing a novel approach to utilize the green gas CO2, in which the activation of CO2 is the key procedure. Among the many catalytic systems employed in the carboxylation, the concept of “Frustrated Lewis Pairs” (FLPs) was scarcely mentioned, which perform excellently in activating small molecules like CO2. The FLPs are combinations of Lewis acids and Lewis bases which failed to form adducts due to their bulky steric congestion. In this paper, we first attempted various Si/Al Based FLPs to catalyze the carboxylation of aromatics through the activation of CO2, and a good yield of 62% - 97% was obtained. The reaction mechanism was proposed, involving the activation of CO2 mainly contributed by AlCl3 in cooperation with organosilane, forming an intermediate consisting of CO2, AlCl3, and R4Si, as well as the subsequent electrophilic attack to aromatics, thus to promote the carboxylation reaction.展开更多
Boron-nitrogen-hydrogen compounds have been investigated and developed very fast in last decades caused by its excellent hydrogen-storage performances. The bottleneck problem hindering its application is the irreversi...Boron-nitrogen-hydrogen compounds have been investigated and developed very fast in last decades caused by its excellent hydrogen-storage performances. The bottleneck problem hindering its application is the irreversibility after its dehydrogenation. However, the traditional B-N(or B-P) bond can be hindered by connecting with large steric hindrances, which results in the possible reversible hydrogenationdehydrogenation properties. In this research, we analyse the structural characters based on the experiments to obtain the required electronic structure properties for realizing the reversibility of FLPs in the hydrogenation(or dehydrogenation).展开更多
Direct syngas conversion to light olefins on bifunctional oxide-zeolite(OX-ZEO)catalysts is of great interest to both academia and industry,but the role of oxygen vacancy(Vo)in metal oxides and whether the key interme...Direct syngas conversion to light olefins on bifunctional oxide-zeolite(OX-ZEO)catalysts is of great interest to both academia and industry,but the role of oxygen vacancy(Vo)in metal oxides and whether the key intermediate in the reaction mechanism is ketene or methanol are still not well-understood.To address these two issues,we carry out a theoretical study of the syngas conversion on the typical reducible metal oxide,CeO2,using density functional theory calculations.Our results demonstrate that by forming frustrated Lewis pairs(FLPs),the VOs in CeO2 play a key role in the activation of H2 and CO.The activation of H2 on FLPs undergoes a heterolytic dissociative pathway with a tiny barrier of 0.01 eV,while CO is activated on FLPs by combining with the basic site(O atom)of FLPs to form CO2^2-.Four pathways for the conversion of syngas were explored on FLPs,two of which are prone to form ketene and the other two are inclined to produce methanol suggesting a compromise to resolve the debate about the key intermediates(ketene or methanol)in the experiments.Rate constant calculations showed that the route initiating with the coupling of two CO*into OCCO*and ending with the formation of ketene is the dominant pathway,with the neighboring FLPs playing an important role in this pathway.Overall,our study reveals the function of the surface FLPs in the activation of H2 and CO and the reaction mechanism for the production of ketene and methanol for the first time,providing novel insights into syngas conversion over OX-ZEO catalysts.展开更多
Typically, a Lewis acid and a Lewis base can react with each other and form a classical Lewis adduct. The neutralization reaction can however be prevented by ligating the acid and base with bulky substituents and the ...Typically, a Lewis acid and a Lewis base can react with each other and form a classical Lewis adduct. The neutralization reaction can however be prevented by ligating the acid and base with bulky substituents and the resulting complex is known as a "frustrated Lewis pair"(FLP). Since the Lewis acid and base reactivity remains in the formed complex, FLPs can display interesting chemical activities, with promising applications in catalysis. For example, FLPs were shown to function as the first metal-free catalyst for molecular hydrogen activation. This, and other recent applications of FLPs, have opened a new thriving research field. In this short-review, we recapitulate the computational and experimental studies of the H_2 activation by FLPs. We discuss the thus-far uncovered mechanistic aspects, including pre-organization of FLPs,the reaction paths for the activation, the polarization of He H bond and other factors affecting the reactivity. We aim to provide a rather complete mechanistic picture of the H_2 activation by FLPs, which has been under debate for decades since the first discovery of FLPs. This review is meant as a starting point for future studies and a guideline for industrial applications.展开更多
The modulational instability, quantum breathers and two-breathers in a frustrated easy-axis ferromagnetic zig-zag chain under an external magnetic field are investigated within the Hartree approximation. By means of a...The modulational instability, quantum breathers and two-breathers in a frustrated easy-axis ferromagnetic zig-zag chain under an external magnetic field are investigated within the Hartree approximation. By means of a linear stability analysis, we analytically study the discrete modulational instability and analyze the effect of the frustration strength on the discrete modulational instability region. Using the results from the discrete modulational instability analysis, the presence conditions of those stationary bright type localized solutions are presented. On the other hand, we obtain the analytical expressions for the stationary bright localized solutions and analyze the effect of the frustration on their emergence conditions. By taking advantage of these bright type single-magnon bound wave functions obtained, quantum breather states in the present frustrated ferromagnetic zig-zag lattice are constructed. What is more, the analytical forms for quantum two-breather states are also obtained. In particular, the energy level formulas of quantum breathers and two-breathers are derived.展开更多
Benzimidazoles are very important chemical materials in the pharmaceutical industry,and the most common synthetic route is cyclization of o-phenylenediamine with carbon sources,in which utilization of inexpensive and ...Benzimidazoles are very important chemical materials in the pharmaceutical industry,and the most common synthetic route is cyclization of o-phenylenediamine with carbon sources,in which utilization of inexpensive and abundant CO_(2)as C1 source is very impressive.Porous aromatic frameworks(PAFs)with highly desired skeletons have attracted great attentions in gas capture and catalysis.Herein,B-based PAF-165 and PAF-166 are designed and synthesized via Friedel-Crafts alkylation reaction,which present high surface areas as well as high stability.Benefiting from the abundant electron-deficient B centers,both PAFs exhibit excellent selective CO_(2)adsorption abilities.The presence of sterically hindered B units in PAFs can act as Lewis acid active sites for the frustrated Lewis pairs(FLPs)in situ formation with ophenylenediamine,thus promoting the synthesis of benzimidazole.The optimal reaction conditions for o-phenylenediamine cyclization with PAF catalysts are explored,and the reaction mechanism is also proposed.This work provides feasible ideas for incorporating FLPs within porous materials as reusable heterogeneous catalysts for CO_(2)capture and conversion.展开更多
A new frustrated triangular lattice antiferromagnet Na_(2)BaNi(PO_(4))_(2) was synthesized by high temperature flux method.The two-dimensional triangular lattice is formed by the Ni^(2+)ions with S=1.Its magnetism is ...A new frustrated triangular lattice antiferromagnet Na_(2)BaNi(PO_(4))_(2) was synthesized by high temperature flux method.The two-dimensional triangular lattice is formed by the Ni^(2+)ions with S=1.Its magnetism is highly anisotropic with the Weiss constants θCW=6.615 K(H||c)and43.979 K(H⊥c).However,no magnetic ordering is present down to 0.3 K,reflecting strong geometric spin frustration.Our heat capacity measurements show substantial residual magnetic entropy existing below 0.3 K at zero field,implying the presence of low energy spin excitations.These results indicate that Na_(2)BaNi(PO_(4))_(2) is a potential spin liquid candidate with spin-1.展开更多
We theoretically investigate the frustrated double ionization(FDI)of molecules with different alignment-dependence using a three-dimensional classical ensemble method.The numerical results show that the FDI probabilit...We theoretically investigate the frustrated double ionization(FDI)of molecules with different alignment-dependence using a three-dimensional classical ensemble method.The numerical results show that the FDI probability decreases with increasing wavelength,which is similar to the wavelength dependence of the FDI probability of atoms.Tracing the classical trajectories reveals that the contributions to molecular FDI from single-recollision and multiple-recollision mechanisms are equal in the short wavelength regime.In the long wavelength regime,the single-recollision FDI channel dominates in FDI.The nature in which molecular FDI occurs is identified and explained.展开更多
Restricted Boltzmann machine(RBM)has been proposed as a powerful variational ansatz to represent the ground state of a given quantum many-body system.On the other hand,as a shallow neural network,it is found that the ...Restricted Boltzmann machine(RBM)has been proposed as a powerful variational ansatz to represent the ground state of a given quantum many-body system.On the other hand,as a shallow neural network,it is found that the RBM is still hardly able to capture the characteristics of systems with large sizes or complicated interactions.In order to find a way out of the dilemma,here,we propose to adopt the Green's function Monte Carlo(GFMC)method for which the RBM is used as a guiding wave function.To demonstrate the implementation and effectiveness of the proposal,we have applied the proposal to study the frustrated J_(1)-J_(2)Heisenberg model on a square lattice,which is considered as a typical model with sign problem for quantum Monte Carlo simulations.The calculation results demonstrate that the GFMC method can significantly further reduce the relative error of the ground-state energy on the basis of the RBM variational results.This encourages to combine the GFMC method with other neural networks like convolutional neural networks for dealing with more models with sign problem in the future.展开更多
基金supported by the National Natural Science Foundation of China(22302115,22072079)the Fundamental Research Program of Shanxi Province(202303021221056).
文摘Heterogeneous solid frustrated-Lewis-pair(FLP)catalyst is of great promise in practical hydrogenation applications.It has been found that all-solid FLPs can be created on ceria via surface oxygen vacancy regulation.Consequently,it is desired to investigate the mechanisms of the FLP-catalyzed hydrogenation of C=C and C=O and provide insight into the modification of CeO_(2)catalysts for the selective hydrogenation.In this work,the reaction mechanism of the hydrogenation of CH_(2)=CH_(2)and CH_(3)CH=O at the FLP sites constructed on CeO_(2)(110)surface was investigated by density functional theory(DFT),with the classical Lewis acid-base pairs(CLP)site as the reference.The results illustrate that at the CLP site,the dissociated hydride(H^(δ−))forms a stable H−O bond with the surface O atom,while at the FLP site,H^(δ−)is stabilized by Ce,displaying higher activity on the one hand.On the other hand,the electron cloud density of the Ce atom at the FLP site is higher,which can transfer more electrons to the adsorbed C_(C=C)and O_(C=O)atoms,leading to a higher degree of activation for C=C and C=O bonds,as indicated by the Bader charge analysis.Therefore,compared to the CLP site,the FLP site exhibits higher hydrogenation activity for CH_(2)=CH_(2)and CH_(3)CH=O.Furthermore,at the FLP sites,it demonstrates high efficiency in catalyzing the hydrogenation of CH_(2)=CH_(2)with the rate-determining barrier of 1.04 eV,but it shows limited activity for the hydrogenation of CH_(3)CH=O with the rate-determining barrier of 1.94 eV.It means that the selective hydrogenation of C=C can be effectively achieved at the FLP sites concerning selective hydrogenation catalysis.The insights shown in this work help to clarify the reaction mechanism of the hydrogenation of C=C and C=O at FLP site on CeO_(2)(110)and reveal the relationship between the catalytic performance and the nature of the active site,which is of great benefit to development of rational design of heterogeneous FLP catalysts.
文摘The development of solid frustrated Lewis pairs(FLPs)catalysts with porous structures is a promising strategy for advancing green hydrogenation technologies and has garnered significant attention.Leveraging the diverse oxidation states and structural tunability of cerium-based metal-organic frameworks(Ce-MOFs),this study employed a competitive coordination strategy utilizing a single carboxylate functional group ligand to construct a series of MOF-808-X(X=-NH_(2),-OH,-Br,and-NO_(2))featuring rich solid-state FLPs for hydrogenation of unsaturated olefins.The-X functional group serves as a microenvironment,enhancing hydrogenation activity by modulating the electronic properties and acid-base characteristics of the FLP sites.The unique redox properties of elemental cerium facilitate the exposure of unsaturated Ce sites(Ce-CUS,Lewis acid(LA))and adjacent Ce-OH(Lewis base(LB))sites within the MOFs,generating abundant solid-state FLP(Ce-CUS/Ce-OH)sites.Experimental results demonstrate that Ce-CUS and Ce-OH interact with theσandσ^(*)orbitals of H-H,and this"push-pull"synergy promotes heterolytic cleavage of the H-H bond.The lone pair electrons of the electron-donating functional group are transmitted through the molecular backbone to the LB site,thereby increasing its strength and reducing the activation energy required for H_(2)heterolytic cleavage.Notably,at 100℃and 2 MPa H_(2),MOF-808-NH_(2)achieves complete conversion of styrene and dicyclopentadiene,significantly outperforming MOF-808.Based on in-situ analysis and density functional theory calculations,a plausible reaction mechanism is proposed.This research enriches the theoretical framework for unsaturated olefin hydrogenation catalysts and contributes to the development of efficient catalytic systems.
基金supported by the National Natural Science Foundation of China(52162036,52174284 and 22378342)the Key Project of Nature Science Foundation of Xinjiang Province(2021D01D08)the Key Research and Development Program of Hunan Province(2024JK2094).
文摘Long-cycling dendrite-free solid-state lithium metal batteries (LMBs) require fast and uniform lithium-ion (Liþ)transport of solid-state electrolytes (SSEs). However, the SSEs still face the problems of low ionic conductivity, lowLiþ transference number, and unstable interface with lithium metal. In this work, a novel strategy of frustratedLewis pairs (FLPs) modulating solid polymer electrolytes (SPEs) has been firstly proposed that enables durable Lireversible cycling. The tunable strength of Lewis acid and base dual-active sites of nickel borate FLPs can syn-ergisticallypromote both the dissociation of lithium salts and the transfer of Liþ. As a consequence, the FLPsmodulated SPEs (SPE-NiBO-150) exhibit high ionic conductivity of 4.92×10^(-4)S cm^(-1), high Liþ transferencenumber of 0.74, and superior interface compatibility with both lithium anode and LiFePO4 cathode at room-temperature.The Li//SPE-NiBO-150//Li symmetric cell demonstrates ultralong cycle stability (over 10,000 h(417 days) at both current density of 0.2 and 0.5 mA cm〓〓2), and the assembled solid-state LiFePO4//SPE-NiBO-150//Libattery also shows excellent performance (86% capacity retention for 300 cycles at 0.5C). The presentwork supplies a new insight into designing high-performance SPEs for solid-state LMB applications.
基金supported by National Natural Science Foundation of China(22075112)Opening Foundation of State Key Laboratory of Rare Earth Resource Utilization(RERU2023010)+1 种基金Opening Foundation of Key Laboratory of Functional Inorganic Material Chemistry(Heilongjiang University)Ministry of Education,China,Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_4006).
文摘Catalytic reduction of 4-nitrophenol(4-NP)pollutant to the high-value 4-aminophenol(4-AP)with a clean hydrogen donor holds significant importance yet great challenges owing to the difficult activation of nitro and H species.In this work,Ag tailoring Frustrated Lewis pairs(FLPs)of CeO_(2)(Ag/CeO_(2))were successfully fabricated for electrochemical reduction reaction of 4-NP(4-NP ERR).As a result,the bond of Ag with O atom changed the state of the Ce-O bond and electron density,where the tailored FLPs were the key factor for enhancing absorption and activation.The reaction rate of Ag/CeO_(2)reached up to 4.70 mmol·min^(-1)(Faraday efficiency:99.5%),which was about four times of CeO_(2).Additionally,this study delved into the proton-coupled electron processes to further understand the mechanism of 4-NP ERR.Therefore,in this study,we have endeavored to investigate the role of tailored FLPs sites and utilize this structure-function relationship to achieve environmentalfriendly chemical synthesis.
基金financially supported by National Natural Science Foundation of China(Nos.52301011,52231008,52142304,52177220,U23A200767,52302236,and 22369005)Hainan Provincial Natural Science Foundation of China(Nos.524QN226 and 524QN222)+2 种基金the Key Research and Development Program of Hainan Province(No.ZDYF2022GXJS006)Starting Research Fund from the Hainan University(No.KYQD(ZR)23026)International Science&Technology Cooperation Program of Hainan Province(No.GHYF2023007).
文摘The alkaline hydrogen evolution reaction(HER)is a crucial process for sustainable hydrogen production,yet it requires efficient and stable electrocatalysts to overcome the high activation energy barrier.The article discusses a novel strategy for enhancing the performance of Ni-Fe layered double hydroxide(Ni-Fe LDH)in the alkaline HER by modifying it with a frustrated Lewis acid-base pair(FLP)constructed through vacancy engineering.The study found that the modified Ni-Fe LDH exhibited improved alkaline HER performance.Density functional theory(DFT)calculations demonstrate that the introduction of FLP can activate water and protons more efficiently than monometallic sites,thus reducing the alkaline HER energy barrier and overpotential.In HER under alkaline conditions,the Volmer step involves an additional hydrolysis dissociation compared to acidic conditions,which is one of the factors contributing to the slow reaction kinetics.This paper demonstrates that FLPs can alter the rate-determining step in alkaline HER from the Volmer step to a step with a lower energy barrier,more suitable for hydrogen desorption.The work provides new insights into the role of FLPs in regulating the mechanism and kinetics of HER and opens a new direction for the design and optimization of LDH-based and other electrocatalysts.
基金supported by the National Key Research and Development Program of China(No.2021YFB3500700)the National Natural Science Foundation of China(No.51972024)+1 种基金Natural Science Foundation of Guangdong Province(No.2022A1515010185)Fundamental Research Funds for the Central Universities(No.FRFEYIT-23-07).
文摘The construction of frustrated Lewis acid-base pairs(FLPs)in porous systems is very important for the field of industrial hydrogenation catalysis,but there is still a great challenge.Based on the Ce^(3+)/Ce^(4+)redox pairs and abundant defects in porous Ce-based metal-organic frameworks(Ce-MOFs),FLP sites consisting of ligand-defective Ce sites(Lewis acid,LA)and neighboring terminal O sites(Lewis base,LB)were constructed in situ by a simple vacuum thermal activation method in lamellar Ce-UiO-66-F.Defects/oxygen vacancies in the Ce-MOFs structure result in the difference in the electron cloud density between Ce and O,which is suitable for H-H hetero-cleavage and H-transfer in the dicyclopentadiene(DCPD)hydrogenation process.Particularly,Ce-UiO-66-F-200 achieved 96.9%conversion of DCPD and 97.8%selectivity of 8,9-dihydrodicyclopentadiene(8,9-DHDCPD)at 100℃ under 2MPa H2 for 10 h,which is 9.4 times higher than 10.2%conversion of DCPD over the unactivated Ce-UiO-66-F.This research promotes the understanding of solid MOFs-based porous FLPs for H_(2) activation,and encourages the in-depth investigation of surface solid FLPs to the whole material FLPs.
基金supports by the National Key Research and Development Program of China (Grant No.2024YFA1409200)the National Natural Science Foundation of China (Grant Nos.12222412 and 12047503)+1 种基金CAS Project for Young Scientists in Basic Research (Grant No.YSBR-057)supports by the National Natural Science Foundation of China (Grant No.12374144)。
文摘We extend a semiclassical numerical method, bosonic auxiliary-field Monte Carlo, to quantum spin systems. This method breaks the lattice into clusters, solves each cluster precisely and couples them with classical auxiliary fields through classical Monte Carlo simulation. We test the method with antiferromagnetic spin models in one-dimensional chains, square lattices and triangular lattices, and obtain reasonable results at finite temperatures. This algorithm builds a bridge between classical Monte Carlo method and quantum methods. The algorithm can be improved with either progress in classical Monte Carlo sampling or the development of quantum solvers, and can also be further applied to systems with different lattices or interactions.
基金supported by the Beijing Natural Science Foundation(Z180013)(YC)National Natural Science Foundation of China(NSFC)under Grant No.12174358(YC)and No.11734010(YC and CW)MOST Grant No.2016YFA0301600(CW)。
文摘Density order is usually a consequence of the competition between long-range and short-range interactions.Here we report a density ordered superfluid emergent from a homogeneous Mott insulator due to the competition between frustrations and local interactions.This transition is found in a Bose–Hubbard model on a frustrated triangle lattice with an extra pairing term.Furthermore,we find a quantum phase transition between two different density ordered superfluids,which is beyond the Landau–Ginzburg(LG)paradigm.A U(1)symmetry is emergent at the critical point,while the symmetry in each density ordered superfluid is Z_(2)×Z_(3).We call the transition a‘shamrock transition’,due to its degenerate ground state in the parameter space being a shamrock-like curve rather than a circle in an LG-type transition.Effective low energy theories are established for the two transitions mentioned above and we find their resemblance and differences with clock models.
文摘Carboxylation of aromatics by CO2 to generate corresponding carboxylic acids is recently providing a novel approach to utilize the green gas CO2, in which the activation of CO2 is the key procedure. Among the many catalytic systems employed in the carboxylation, the concept of “Frustrated Lewis Pairs” (FLPs) was scarcely mentioned, which perform excellently in activating small molecules like CO2. The FLPs are combinations of Lewis acids and Lewis bases which failed to form adducts due to their bulky steric congestion. In this paper, we first attempted various Si/Al Based FLPs to catalyze the carboxylation of aromatics through the activation of CO2, and a good yield of 62% - 97% was obtained. The reaction mechanism was proposed, involving the activation of CO2 mainly contributed by AlCl3 in cooperation with organosilane, forming an intermediate consisting of CO2, AlCl3, and R4Si, as well as the subsequent electrophilic attack to aromatics, thus to promote the carboxylation reaction.
基金supported by the National Key Research and Development Program of China(2017YFA0204600)National Natural Science Foundation of China(NSFC 21701001,51625102)+1 种基金Anhui Provincial Natural Science Foundation(1708085QB42)China Postdoctoral Science Foundation(2018M632013)
文摘Boron-nitrogen-hydrogen compounds have been investigated and developed very fast in last decades caused by its excellent hydrogen-storage performances. The bottleneck problem hindering its application is the irreversibility after its dehydrogenation. However, the traditional B-N(or B-P) bond can be hindered by connecting with large steric hindrances, which results in the possible reversible hydrogenationdehydrogenation properties. In this research, we analyse the structural characters based on the experiments to obtain the required electronic structure properties for realizing the reversibility of FLPs in the hydrogenation(or dehydrogenation).
文摘Direct syngas conversion to light olefins on bifunctional oxide-zeolite(OX-ZEO)catalysts is of great interest to both academia and industry,but the role of oxygen vacancy(Vo)in metal oxides and whether the key intermediate in the reaction mechanism is ketene or methanol are still not well-understood.To address these two issues,we carry out a theoretical study of the syngas conversion on the typical reducible metal oxide,CeO2,using density functional theory calculations.Our results demonstrate that by forming frustrated Lewis pairs(FLPs),the VOs in CeO2 play a key role in the activation of H2 and CO.The activation of H2 on FLPs undergoes a heterolytic dissociative pathway with a tiny barrier of 0.01 eV,while CO is activated on FLPs by combining with the basic site(O atom)of FLPs to form CO2^2-.Four pathways for the conversion of syngas were explored on FLPs,two of which are prone to form ketene and the other two are inclined to produce methanol suggesting a compromise to resolve the debate about the key intermediates(ketene or methanol)in the experiments.Rate constant calculations showed that the route initiating with the coupling of two CO*into OCCO*and ending with the formation of ketene is the dominant pathway,with the neighboring FLPs playing an important role in this pathway.Overall,our study reveals the function of the surface FLPs in the activation of H2 and CO and the reaction mechanism for the production of ketene and methanol for the first time,providing novel insights into syngas conversion over OX-ZEO catalysts.
文摘Typically, a Lewis acid and a Lewis base can react with each other and form a classical Lewis adduct. The neutralization reaction can however be prevented by ligating the acid and base with bulky substituents and the resulting complex is known as a "frustrated Lewis pair"(FLP). Since the Lewis acid and base reactivity remains in the formed complex, FLPs can display interesting chemical activities, with promising applications in catalysis. For example, FLPs were shown to function as the first metal-free catalyst for molecular hydrogen activation. This, and other recent applications of FLPs, have opened a new thriving research field. In this short-review, we recapitulate the computational and experimental studies of the H_2 activation by FLPs. We discuss the thus-far uncovered mechanistic aspects, including pre-organization of FLPs,the reaction paths for the activation, the polarization of He H bond and other factors affecting the reactivity. We aim to provide a rather complete mechanistic picture of the H_2 activation by FLPs, which has been under debate for decades since the first discovery of FLPs. This review is meant as a starting point for future studies and a guideline for industrial applications.
基金Project supported by the National Natural Science Foundation of China(Grant No.11604121)the Scientific Research Fund of Hunan Provincial Education Department,China(Grant Nos.16B210 and 16A170)the Natural Science Fund Project of Jishou University,China(Grant No.jdx17036)
文摘The modulational instability, quantum breathers and two-breathers in a frustrated easy-axis ferromagnetic zig-zag chain under an external magnetic field are investigated within the Hartree approximation. By means of a linear stability analysis, we analytically study the discrete modulational instability and analyze the effect of the frustration strength on the discrete modulational instability region. Using the results from the discrete modulational instability analysis, the presence conditions of those stationary bright type localized solutions are presented. On the other hand, we obtain the analytical expressions for the stationary bright localized solutions and analyze the effect of the frustration on their emergence conditions. By taking advantage of these bright type single-magnon bound wave functions obtained, quantum breather states in the present frustrated ferromagnetic zig-zag lattice are constructed. What is more, the analytical forms for quantum two-breather states are also obtained. In particular, the energy level formulas of quantum breathers and two-breathers are derived.
基金the financial support by the Fundamental Research Funds for the Central Universities(No.2412019FZ008)the National Natural Science Foundation of China(Nos.22131004 and U21A20330)the"111 Project(No.B18012)。
文摘Benzimidazoles are very important chemical materials in the pharmaceutical industry,and the most common synthetic route is cyclization of o-phenylenediamine with carbon sources,in which utilization of inexpensive and abundant CO_(2)as C1 source is very impressive.Porous aromatic frameworks(PAFs)with highly desired skeletons have attracted great attentions in gas capture and catalysis.Herein,B-based PAF-165 and PAF-166 are designed and synthesized via Friedel-Crafts alkylation reaction,which present high surface areas as well as high stability.Benefiting from the abundant electron-deficient B centers,both PAFs exhibit excellent selective CO_(2)adsorption abilities.The presence of sterically hindered B units in PAFs can act as Lewis acid active sites for the frustrated Lewis pairs(FLPs)in situ formation with ophenylenediamine,thus promoting the synthesis of benzimidazole.The optimal reaction conditions for o-phenylenediamine cyclization with PAF catalysts are explored,and the reaction mechanism is also proposed.This work provides feasible ideas for incorporating FLPs within porous materials as reusable heterogeneous catalysts for CO_(2)capture and conversion.
基金Project supported by the National Natural Science Foundation of China(Grant No.11804137)the Natural Science Foundation of Shandong Province,China(Grant Nos.ZR2020YQ03 and ZR2018BA026).
文摘A new frustrated triangular lattice antiferromagnet Na_(2)BaNi(PO_(4))_(2) was synthesized by high temperature flux method.The two-dimensional triangular lattice is formed by the Ni^(2+)ions with S=1.Its magnetism is highly anisotropic with the Weiss constants θCW=6.615 K(H||c)and43.979 K(H⊥c).However,no magnetic ordering is present down to 0.3 K,reflecting strong geometric spin frustration.Our heat capacity measurements show substantial residual magnetic entropy existing below 0.3 K at zero field,implying the presence of low energy spin excitations.These results indicate that Na_(2)BaNi(PO_(4))_(2) is a potential spin liquid candidate with spin-1.
基金Supported by the National Natural Science Foundation of China(Grant Nos.12004323,12074329,12104389,1174131 and 91850114)National Key R&D Program of China(2022YFE0134200)+2 种基金Nanhu Scholars Program for Young Scholars of Xinyang Normal UniversityNatural Science Foundation of Jilin Province,China(Grant No.20220101016JC)the Open Research Fund of State Key Laboratory of Transient Optics and Photonics。
文摘We theoretically investigate the frustrated double ionization(FDI)of molecules with different alignment-dependence using a three-dimensional classical ensemble method.The numerical results show that the FDI probability decreases with increasing wavelength,which is similar to the wavelength dependence of the FDI probability of atoms.Tracing the classical trajectories reveals that the contributions to molecular FDI from single-recollision and multiple-recollision mechanisms are equal in the short wavelength regime.In the long wavelength regime,the single-recollision FDI channel dominates in FDI.The nature in which molecular FDI occurs is identified and explained.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11934020 and 11874421)the Natural Science Foundation of Beijing(Grant No.Z180013)。
文摘Restricted Boltzmann machine(RBM)has been proposed as a powerful variational ansatz to represent the ground state of a given quantum many-body system.On the other hand,as a shallow neural network,it is found that the RBM is still hardly able to capture the characteristics of systems with large sizes or complicated interactions.In order to find a way out of the dilemma,here,we propose to adopt the Green's function Monte Carlo(GFMC)method for which the RBM is used as a guiding wave function.To demonstrate the implementation and effectiveness of the proposal,we have applied the proposal to study the frustrated J_(1)-J_(2)Heisenberg model on a square lattice,which is considered as a typical model with sign problem for quantum Monte Carlo simulations.The calculation results demonstrate that the GFMC method can significantly further reduce the relative error of the ground-state energy on the basis of the RBM variational results.This encourages to combine the GFMC method with other neural networks like convolutional neural networks for dealing with more models with sign problem in the future.
