The high-efficiency conversion of biomass resources to biofuels has attracted widespread attention, and the active sites and synergistic effect of catalysts significantly impact their surface arrangement and electroni...The high-efficiency conversion of biomass resources to biofuels has attracted widespread attention, and the active sites and synergistic effect of catalysts significantly impact their surface arrangement and electronic structure. Here, a nickel-based transition metal carbide catalyst(Ni/TMC) with high Lewis acidity was prepared by self-assembly of transition metal carbide(TMC) and nickel, which exhibited excellent performance on synergistic hydrogenation and hydrogenolysis of 5-hydroxymethylfurfural(HMF) into liquid biofuel 2,5-dimethylfuran(DMF).Notably, Ni/WC with the highest Lewis acidity(4728.3 μmol g^(-1)) can achieve 100% conversion of HMF to 97.6% yield of DMF, with a turnover frequency of up to 46.5 h^(-1). The characterization results demonstrate that the rich Lewis acid sites yielded by the synergistic effect between Ni species and TMC are beneficial for the C=O hydrogenation and C–O cleavage, thereby accelerating the process of hydrodeoxygenation(HDO). Besides, a kinetic model for the HDO of HMF to DMF process has been established based on the experimental results, which elucidated a significant correlation between the measured and the predicted data(R^(2)> 0.97). Corresponding to the adsorption configuration of Ni/WC and substrate determined by in-situ FTIR characterization, this study provides a novel insight into the selective conversion of HMF process for functional biofuel and bio-chemicals.展开更多
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
Direct electrolysis of seawater offers a transformative technology for sustainable hydrogen production,circumventing the constraint of freshwater scarcity.However,the serious electrode corrosion and competitive chlori...Direct electrolysis of seawater offers a transformative technology for sustainable hydrogen production,circumventing the constraint of freshwater scarcity.However,the serious electrode corrosion and competitive chloride oxidation reactions make oxygen evolution reaction(OER)in seawater extremely challenging.Herein,the low-cost and scalable CoFe layered double hydroxides with Cl^(-)intercalation and decorated with Ce(OH)_(3)(named as CoFe-Cl^(-)/Ce(OH)_(3))catalyst is synthesized via rapid electrodeposition under ambient conditions,which is quickly reconstructed into a CeO_(2)decorated and Cl^(-)intercalated CoFeOOH(CoFeOOH-Cl^(-)/CeO_(2))during OER.Theoretical investigation reveals that Cl^(-)intercalation weakens the adsorption ability of Cl^(-)on Co/Fe atoms and hinders unfavorable coupling with chloride,thereby preventing the chlorine corrosion process and enhancing catalytic stability and activity.The CeO_(2)with hard Lewis acidity preferentially binds to OH-with harder Lewis base to ensure the OH-rich microenvironment around catalyst even under high current operating conditions,thus further enhancing stability and improving OER activity.The functionalized CoFe-Cl^(-)/Ce(OH)_(3)delivers 1000 mA cm^(-2)current density at only 329 mV overpotential with excellent stability for 1000 h under alkaline seawater.Electrochemical experiments elucidate the OER catalytic mechanism in which CeO_(2)serves as a co-catalyst for enriching OH-and CoFeOOH-Cl^(-)is the active species.Our work is a substantial step towards achieving massive and sustainable production of hydrogen fuel from immense seawater.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
High-capacity LiBH_(4)is a promising solid hydrogen storage material.However,the large electron cloud density between the B-H bonds in LiBH_(4)induces high dehydrogenation temperatures and sluggish dehydrogenation kin...High-capacity LiBH_(4)is a promising solid hydrogen storage material.However,the large electron cloud density between the B-H bonds in LiBH_(4)induces high dehydrogenation temperatures and sluggish dehydrogenation kinetics.To solve the above problems,it is proposed to enhance the hydrogen storage properties of LiBH_(4)through the synergistic effect of Brønsted and Lewis acid in Hβzeolite.Composite hydrogen storage systems with different mass ratios were prepared by simple ball-milling.At a LiBH_(4)-to-Hβmass ratio of 6:4,the 6LiBH_(4)-4Hβsystem released hydrogen at 190℃and achieved a hydrogen release capacity of 7.0 wt%H_(2)upon heating to 400℃.More importantly,the hydrogen release capacity of the system reached 6.02 wt%at 350℃under isothermal conditions after 100 min and 7.2 wt%at 400℃under isothermal conditions after 80 min,whereas the pristine LiBH_(4)only achieved 2.2 wt%.The improvement in hydrogen storage performance of the system was mainly attributed to two factors:(i)Lewis acid sites with acceptable electrons in the Hβweaken the electron density of B-H bonds in LiBH_(4),and(ii)the H+proton from the Brønsted acid sites and H−of LiBH_(4)undergo a H^(+)+H^(−)=H_(2)reaction.Theoretical calculations revealed that the Lewis and Brønsted acid sites in the Hβzeolite are conducive to the weakening of B-H bonds and that storage charge transfer occurs near the Lewis acid sites.The present work provides new insights into improving the hydrogen storage performance of LiBH_(4)by weakening the B-H bonds in the LiBH_(4).展开更多
A series of amine-bridged bis(phenolate)rare-earth(Sc,Y)aryloxides was synthesized and characterized.These complexes were successfully used for the controlled Lewis pair polymerization(LPP)of functional acrylamides in...A series of amine-bridged bis(phenolate)rare-earth(Sc,Y)aryloxides was synthesized and characterized.These complexes were successfully used for the controlled Lewis pair polymerization(LPP)of functional acrylamides in combination with phosphines,affording a new type of polyacrylamides with predictable molecular weight and low molecular weight distribution.The living nature of this LPP was verified by near-quantitative initiation efficiencies,a linear increase of molecular weight vs monomer-to-initiator ratio and monomer conversion,chain extensions,and the synthesis of well-defined block copolymers.The mechanistic studies were performed through the isolation of a zwitterionic intermediate as well as the end-chain analysis of oligomers,showcasing a rare-earth/phosphine cooperation.Furthermore,the resultant polyacrylamides exhibit outstanding thermal stability and great potential for application in photovoltaic devices.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 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
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
基金Fundamental Research Foundation of CAF (CAFYBB2022QB001)National Nature Science Foundation of China for Excellent Young Scientists Fund (32222058)。
文摘The high-efficiency conversion of biomass resources to biofuels has attracted widespread attention, and the active sites and synergistic effect of catalysts significantly impact their surface arrangement and electronic structure. Here, a nickel-based transition metal carbide catalyst(Ni/TMC) with high Lewis acidity was prepared by self-assembly of transition metal carbide(TMC) and nickel, which exhibited excellent performance on synergistic hydrogenation and hydrogenolysis of 5-hydroxymethylfurfural(HMF) into liquid biofuel 2,5-dimethylfuran(DMF).Notably, Ni/WC with the highest Lewis acidity(4728.3 μmol g^(-1)) can achieve 100% conversion of HMF to 97.6% yield of DMF, with a turnover frequency of up to 46.5 h^(-1). The characterization results demonstrate that the rich Lewis acid sites yielded by the synergistic effect between Ni species and TMC are beneficial for the C=O hydrogenation and C–O cleavage, thereby accelerating the process of hydrodeoxygenation(HDO). Besides, a kinetic model for the HDO of HMF to DMF process has been established based on the experimental results, which elucidated a significant correlation between the measured and the predicted data(R^(2)> 0.97). Corresponding to the adsorption configuration of Ni/WC and substrate determined by in-situ FTIR characterization, this study provides a novel insight into the selective conversion of HMF process for functional biofuel and bio-chemicals.
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financial support from the National Natural Science Foundation of China(52372173,52072034)。
文摘Direct electrolysis of seawater offers a transformative technology for sustainable hydrogen production,circumventing the constraint of freshwater scarcity.However,the serious electrode corrosion and competitive chloride oxidation reactions make oxygen evolution reaction(OER)in seawater extremely challenging.Herein,the low-cost and scalable CoFe layered double hydroxides with Cl^(-)intercalation and decorated with Ce(OH)_(3)(named as CoFe-Cl^(-)/Ce(OH)_(3))catalyst is synthesized via rapid electrodeposition under ambient conditions,which is quickly reconstructed into a CeO_(2)decorated and Cl^(-)intercalated CoFeOOH(CoFeOOH-Cl^(-)/CeO_(2))during OER.Theoretical investigation reveals that Cl^(-)intercalation weakens the adsorption ability of Cl^(-)on Co/Fe atoms and hinders unfavorable coupling with chloride,thereby preventing the chlorine corrosion process and enhancing catalytic stability and activity.The CeO_(2)with hard Lewis acidity preferentially binds to OH-with harder Lewis base to ensure the OH-rich microenvironment around catalyst even under high current operating conditions,thus further enhancing stability and improving OER activity.The functionalized CoFe-Cl^(-)/Ce(OH)_(3)delivers 1000 mA cm^(-2)current density at only 329 mV overpotential with excellent stability for 1000 h under alkaline seawater.Electrochemical experiments elucidate the OER catalytic mechanism in which CeO_(2)serves as a co-catalyst for enriching OH-and CoFeOOH-Cl^(-)is the active species.Our work is a substantial step towards achieving massive and sustainable production of hydrogen fuel from immense seawater.
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 the National Natural Science Foundation of China(No.52201274)the Project of Education Department of Shanxi Province(No.22JK0419).
文摘High-capacity LiBH_(4)is a promising solid hydrogen storage material.However,the large electron cloud density between the B-H bonds in LiBH_(4)induces high dehydrogenation temperatures and sluggish dehydrogenation kinetics.To solve the above problems,it is proposed to enhance the hydrogen storage properties of LiBH_(4)through the synergistic effect of Brønsted and Lewis acid in Hβzeolite.Composite hydrogen storage systems with different mass ratios were prepared by simple ball-milling.At a LiBH_(4)-to-Hβmass ratio of 6:4,the 6LiBH_(4)-4Hβsystem released hydrogen at 190℃and achieved a hydrogen release capacity of 7.0 wt%H_(2)upon heating to 400℃.More importantly,the hydrogen release capacity of the system reached 6.02 wt%at 350℃under isothermal conditions after 100 min and 7.2 wt%at 400℃under isothermal conditions after 80 min,whereas the pristine LiBH_(4)only achieved 2.2 wt%.The improvement in hydrogen storage performance of the system was mainly attributed to two factors:(i)Lewis acid sites with acceptable electrons in the Hβweaken the electron density of B-H bonds in LiBH_(4),and(ii)the H+proton from the Brønsted acid sites and H−of LiBH_(4)undergo a H^(+)+H^(−)=H_(2)reaction.Theoretical calculations revealed that the Lewis and Brønsted acid sites in the Hβzeolite are conducive to the weakening of B-H bonds and that storage charge transfer occurs near the Lewis acid sites.The present work provides new insights into improving the hydrogen storage performance of LiBH_(4)by weakening the B-H bonds in the LiBH_(4).
基金supported by National Natural Science Foundation of China(21871204,22371198)Postgraduate Research&Practice Innovation Program of Jiangsu Province。
文摘A series of amine-bridged bis(phenolate)rare-earth(Sc,Y)aryloxides was synthesized and characterized.These complexes were successfully used for the controlled Lewis pair polymerization(LPP)of functional acrylamides in combination with phosphines,affording a new type of polyacrylamides with predictable molecular weight and low molecular weight distribution.The living nature of this LPP was verified by near-quantitative initiation efficiencies,a linear increase of molecular weight vs monomer-to-initiator ratio and monomer conversion,chain extensions,and the synthesis of well-defined block copolymers.The mechanistic studies were performed through the isolation of a zwitterionic intermediate as well as the end-chain analysis of oligomers,showcasing a rare-earth/phosphine cooperation.Furthermore,the resultant polyacrylamides exhibit outstanding thermal stability and great potential for application in photovoltaic devices.
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.
