By using solvothermal method, two new main group metal coordination polymers based on 2,5-furandicarboxylic acid （H2FDA） ligand, [Sr2（FDA）E（H2O）5]n （1） and [Ba4（FDA）4（H2O）10]n （2）, were produced and char...By using solvothermal method, two new main group metal coordination polymers based on 2,5-furandicarboxylic acid （H2FDA） ligand, [Sr2（FDA）E（H2O）5]n （1） and [Ba4（FDA）4（H2O）10]n （2）, were produced and characterized by single-crystal X-ray diffraction analyses, elemental analyses, IR, and powder X-ray diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 13.454（3）, b = 13.426（3）, c = 20.166（4） A, β = 107.06（3）°, V = 3482.4（13）A^3, Dc = 2.188 g/cm^3, CIEH14Sr2O15, Mr = 573.47, F（000） = 2256,μ（MoKα）= 6.21 mm^-1, Z = 8, R = 0.0522 and wR = 0.1229 for 2493 observed reflections （I〉 2σ（I））, and R = 0.0689 and wR = 0.1324 for all data. Compound 2 crystallizes in triclinic, space group el with α = 6.8382（14）, b = 10.932（2）, c = 25.571（5） A,α = 94.64（3）, β= 95.41（3）, γ = 107.83（3）°, V= 1799.4（6） A3, Dc = 2.484 g/cm^3, C24H28Ba4O30, Mr = 1345.82, F（000） = 1272,μ（MoKa） = 4.43 mm^-1, Z = 2, R = 0.0485 and wR = 0.0906 for 5020 observed reflections （I〉 2σ（I））, and R = 0.0706 and wR = 0.0991 for all data. In 1, the trinuclear clusters Sr3 are connected with adjacent four clusters by a carboxylate group to produce a two-dimensional （2D） sheet, which is extended by a FDA-based pillar into a 3D framework. In 2, neighbouring trinuclear clusters Ba3 are linked through two -O-C-O- of FDA^2- ligands to form one-dimensional （1D） chains, which are connected by a FDA-based pillar to construct a 2D framework. The thermal stabilities of 1 and 2 are also investigated.展开更多
New appronches were applied to improve the molecular connectivity indices m^X^τ. The vertex valence is redefined and it was reasonable for hydrogen atom. The distances between vertices were used to propose novel conn...New appronches were applied to improve the molecular connectivity indices m^X^τ. The vertex valence is redefined and it was reasonable for hydrogen atom. The distances between vertices were used to propose novel connectivity topological indexes. The vertices and the distances in a molecular graph were taken into account in this definition. The linear regression was used to develop the structural property models. The results indicate that the novel connectivity topological indexes are useful model parameters for Quantitative Strncture-Property Relationship （ QSPR ） analysis.展开更多
Electrocatalytic N_(2) reduction under ambient-condition is considered to be the most appealing strategy to the conventional Haber-Bosch process for synthetic ammonia to alleviate greenhouse emissions and reduce envir...Electrocatalytic N_(2) reduction under ambient-condition is considered to be the most appealing strategy to the conventional Haber-Bosch process for synthetic ammonia to alleviate greenhouse emissions and reduce environmental pollution, mainly powered by renewable energy. Recent years, rapid advances have been gained in this attractive research field, and numerous electrocatalysts have been exploited. However, its conversion efficiency is still far behind the requirement of industrial applications owing to the breakage of the N≡N triple bond, which is an energetically challenging kinetically complex multistep reaction and the strong competing reaction of hydrogen evolution reaction. Recently, main group metal-based catalysts have been demonstrated promising application prospect for ammonia production, significantly boosting their further application in this field. However, a comprehensive review of main group metal-based catalysts towards electrochemical ammonia production applications is still lacking. In this review, the fundamentals of N_(2) reduction, such as the reaction pathways, the reaction potential and the challenges of N_(2) reduction have been comprehensively discussed. And then, the role, mechanism, and effect of each main group element-based catalysts used for N_(2) reduction (Li, K, Al, Ga, Sn, Sb, Bi, and their compounds) are systematically summarized. Finally, several state-of-the-art strategies to promote their NRR catalytic performance, as well as the existing problems and prospects are put forward. This review is expected to guide the design and establishment of more efficient electrocatalytic N_(2) reduction systems based on main group metal elements in the future.展开更多
Photoabsorption charge separation/transfer and surface reaction are the three main factors influencing the efficiency of photocatalysis.Band structure engineering has been extensively applied to improve the light abso...Photoabsorption charge separation/transfer and surface reaction are the three main factors influencing the efficiency of photocatalysis.Band structure engineering has been extensively applied to improve the light absorption of photocatalysts,however,most of the developed photocatalysts still suffer from low photocatalytic performance due to the limited active site(s)and fast recombination of photogenerated charge carriers.In this work,atomically dispersed main group magnesium(Mg)is introduced onto CdS monodispersed nanospheres,which greatly enhances the photocatalytic hydrogen evolution reaction.The photocatalytic hydrogen evolution reaction rate reaches 30.6 mmol·gcatalyst^(-1)·h^(-1),which is about 11.8 and 2.5 times that of pure CdS and Pt(2 wt.%)-CdS.The atomically dispersed Mg on CdS acts as an electron sink to trap photogenerated electrons,and at the same time,greatly reduces the Gibbs free energy of hydrogen evolution reaction(HER)and accelerates HER.展开更多
Two isomers of a sandwich-type anion [Ge_(9)-In-Ge_(9)]^(5–) were synthesized by controlling the chelating agents (2,2,2-crypt/18-C-6). Further reactions with early/late transition metal complexes, Mo(CO)_(6) and Ni(...Two isomers of a sandwich-type anion [Ge_(9)-In-Ge_(9)]^(5–) were synthesized by controlling the chelating agents (2,2,2-crypt/18-C-6). Further reactions with early/late transition metal complexes, Mo(CO)_(6) and Ni(COD)_(2), respectively, yielded two new types of inorganic sandwich derivatives: a half-sandwich cluster [Ge_(9)-In-Mo(CO)_(5)]^(3–) with a low-valence In(I) center and an unsymmetrical sandwich-type cluster {[(Ni@Ge_(9))In(Ni_(0.648)@Ge_(9))]}^(5–) due to the insertion of Ni atoms, respectively. The isolation of these new derivatives demonstrates the reactivity of sandwich-type [Ge_(9)-In-Ge_(9)]^(5–) acting as the precursor, which provides some enlightenment for constructing new inorganic sandwich compounds.展开更多
Designing catalysts with highly active,selectivity,and stability for electrocatalytic CO_(2)to formate is currently a severe challenge.Herein,we developed an electronic structure engineering on carbon nano frameworks ...Designing catalysts with highly active,selectivity,and stability for electrocatalytic CO_(2)to formate is currently a severe challenge.Herein,we developed an electronic structure engineering on carbon nano frameworks embedded with nitrogen and sulfur asymmetrically dual-coordinated indium active sites toward the efficient electrocatalytic CO_(2)reduction reaction.As expected,atomically dispersed In-based catalysts with In-S_(1)N_(3)atomic interface with asymmetrically coordinated exhibited high efficiency for CO_(2)reduction reaction(CO_(2)RR)to formate.It achieved a maximum Faradaic efficiency(FE)of 94.3%towards formate generation at−0.8 V vs.reversible hydrogen electrode(RHE),outperforming that of catalysts with In-S2N2 and In-N4 atomic interface.And at a potential of−1.10 V vs.RHE,In-S_(1)N_(3)achieves an impressive Faradaic efficiency of 93.7%in flow cell.The catalytic performance of In-S_(1)N_(3)sites was confirmed to be enhanced through in-situ X-ray absorption near-edge structure(XANES)measurements under electrochemical conditions.Our discovery provides the guidance for performance regulation of main group metal catalysts toward CO_(2)RR at atomic scale.展开更多
Thousands of landslide data being taken as the nation wide statistics of sampling and the two state variables of landslide being processed with two methods described in the references, the main types of lithologica...Thousands of landslide data being taken as the nation wide statistics of sampling and the two state variables of landslide being processed with two methods described in the references, the main types of lithological groups of landslides in China have been sieved and selected.On the other hand, through the displacement table of Pascal Yanghui triangle used in the information encoding theory, the mark weight of sampling can be calculated and the main lithological groups which have close relationship with landslide occurrence can be gained.In comparison with the both results, the characteristics of main sliding lithological groups are determinated, and the main distribution regions of landslides can be prognosticated.展开更多
A main-chain liquid crystalline ionomer（MLCI） containing sulfonic group was synthesized by an interfacial condensation reaction.The MLCI was blended with polybutylene terephthalate（PBT） and polypropylene（PP）.MLC...A main-chain liquid crystalline ionomer（MLCI） containing sulfonic group was synthesized by an interfacial condensation reaction.The MLCI was blended with polybutylene terephthalate（PBT） and polypropylene（PP）.MLCI interacted with both the dispersed（PP） phase and the matrix（PBT） phase to modify the interfacial interaction of PBT and PP.Differential scanning calorimetry（DSC）,scanning electron microscopy（SEM） and FTIR imaging system analysis demonstrated the significance of interfacial interaction in the polymer blends.MLCI brought about good adhesion at the interfacial,which reduced the disperse phase size and enabled a fine PP phase at matrix.The mechanical properties of the ternary blends were improved when a proper amount of MLCI was added.This was attributed to enhanced adhesion at the interface,which invoked better mechanical properties in the blends.展开更多
Carboranes are a class of polyhedral boron-carbon molecular clusters,they can serve as versatile ligands in stabilizing low-valent main group element compounds,due to their exceptionally thermal and chemical stabiliti...Carboranes are a class of polyhedral boron-carbon molecular clusters,they can serve as versatile ligands in stabilizing low-valent main group element compounds,due to their exceptionally thermal and chemical stabilities,easy modifications at the cage carbon vertices,as well as large spherical steric effects.These carborane-based ligands provide interesting opportunities for the synthesis of low-valent main group element compounds with novel structure and reactivity,which indeed enrich the chemistry of low-valent element main group compounds.This review summarizes the recent advances in the chemistry of lowvalent group 13 and group 14 element compounds supported by carborane-based ligands.Achievements and perspectives in this new and flourishing field are discussed in this review.展开更多
基金supported by URT program of Beijing Institute of Petrochemical Technology(2015J00058 and 2015J00056)
文摘By using solvothermal method, two new main group metal coordination polymers based on 2,5-furandicarboxylic acid （H2FDA） ligand, [Sr2（FDA）E（H2O）5]n （1） and [Ba4（FDA）4（H2O）10]n （2）, were produced and characterized by single-crystal X-ray diffraction analyses, elemental analyses, IR, and powder X-ray diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 13.454（3）, b = 13.426（3）, c = 20.166（4） A, β = 107.06（3）°, V = 3482.4（13）A^3, Dc = 2.188 g/cm^3, CIEH14Sr2O15, Mr = 573.47, F（000） = 2256,μ（MoKα）= 6.21 mm^-1, Z = 8, R = 0.0522 and wR = 0.1229 for 2493 observed reflections （I〉 2σ（I））, and R = 0.0689 and wR = 0.1324 for all data. Compound 2 crystallizes in triclinic, space group el with α = 6.8382（14）, b = 10.932（2）, c = 25.571（5） A,α = 94.64（3）, β= 95.41（3）, γ = 107.83（3）°, V= 1799.4（6） A3, Dc = 2.484 g/cm^3, C24H28Ba4O30, Mr = 1345.82, F（000） = 1272,μ（MoKa） = 4.43 mm^-1, Z = 2, R = 0.0485 and wR = 0.0906 for 5020 observed reflections （I〉 2σ（I））, and R = 0.0706 and wR = 0.0991 for all data. In 1, the trinuclear clusters Sr3 are connected with adjacent four clusters by a carboxylate group to produce a two-dimensional （2D） sheet, which is extended by a FDA-based pillar into a 3D framework. In 2, neighbouring trinuclear clusters Ba3 are linked through two -O-C-O- of FDA^2- ligands to form one-dimensional （1D） chains, which are connected by a FDA-based pillar to construct a 2D framework. The thermal stabilities of 1 and 2 are also investigated.
基金Funded bythe Natural Science andthe Education Office Founda-tion of Hubei Province(No.2005ABA016 and 2004Q002)
文摘New appronches were applied to improve the molecular connectivity indices m^X^τ. The vertex valence is redefined and it was reasonable for hydrogen atom. The distances between vertices were used to propose novel connectivity topological indexes. The vertices and the distances in a molecular graph were taken into account in this definition. The linear regression was used to develop the structural property models. The results indicate that the novel connectivity topological indexes are useful model parameters for Quantitative Strncture-Property Relationship （ QSPR ） analysis.
基金This work was supported by the National Natural Science Foundation of China(No.52071171)the Liaoning Revitalization Talents Program-Pan Deng Scholars(XLYC1802005)+4 种基金the Liaoning Bai-QianWan Talents Program(LNBQW2018B0048)the National Science Fund of Liaoning Province for Excellent Young Scholars(2019-YQ-04)the Key Project of Scientific Research of the Education Department of Liaoning Province(LZD201902)the Department of Education of Liaoning Province(LQN201903 and LQN202008)the Foundation for Young Scholars of Liaoning University(LDQN2019007).
文摘Electrocatalytic N_(2) reduction under ambient-condition is considered to be the most appealing strategy to the conventional Haber-Bosch process for synthetic ammonia to alleviate greenhouse emissions and reduce environmental pollution, mainly powered by renewable energy. Recent years, rapid advances have been gained in this attractive research field, and numerous electrocatalysts have been exploited. However, its conversion efficiency is still far behind the requirement of industrial applications owing to the breakage of the N≡N triple bond, which is an energetically challenging kinetically complex multistep reaction and the strong competing reaction of hydrogen evolution reaction. Recently, main group metal-based catalysts have been demonstrated promising application prospect for ammonia production, significantly boosting their further application in this field. However, a comprehensive review of main group metal-based catalysts towards electrochemical ammonia production applications is still lacking. In this review, the fundamentals of N_(2) reduction, such as the reaction pathways, the reaction potential and the challenges of N_(2) reduction have been comprehensively discussed. And then, the role, mechanism, and effect of each main group element-based catalysts used for N_(2) reduction (Li, K, Al, Ga, Sn, Sb, Bi, and their compounds) are systematically summarized. Finally, several state-of-the-art strategies to promote their NRR catalytic performance, as well as the existing problems and prospects are put forward. This review is expected to guide the design and establishment of more efficient electrocatalytic N_(2) reduction systems based on main group metal elements in the future.
基金We are grateful for the financial support from the Natural Science Foundation of China(51979081)Fundamental Research Funds for the Central Universities(No.B200202103)+2 种基金Ministry of Education of Singapore(Tier 1:RG4/20 and Tier 2:MOET2EP10120-0002)Agency for Science,Technology and Research(AME IRG:A20E5c0080)PAPD。
文摘Photoabsorption charge separation/transfer and surface reaction are the three main factors influencing the efficiency of photocatalysis.Band structure engineering has been extensively applied to improve the light absorption of photocatalysts,however,most of the developed photocatalysts still suffer from low photocatalytic performance due to the limited active site(s)and fast recombination of photogenerated charge carriers.In this work,atomically dispersed main group magnesium(Mg)is introduced onto CdS monodispersed nanospheres,which greatly enhances the photocatalytic hydrogen evolution reaction.The photocatalytic hydrogen evolution reaction rate reaches 30.6 mmol·gcatalyst^(-1)·h^(-1),which is about 11.8 and 2.5 times that of pure CdS and Pt(2 wt.%)-CdS.The atomically dispersed Mg on CdS acts as an electron sink to trap photogenerated electrons,and at the same time,greatly reduces the Gibbs free energy of hydrogen evolution reaction(HER)and accelerates HER.
基金supported by the National Natural Science Foundation of China(Nos.92161102 and 21971118)the Nat-ural Science Foundation of Tianjin City(Nos.21JCZXJC00140 and 20JCYBJC01560)as well as the 111 project(B18030)from Ministry of Education China to Z.M.S.and the Tianjin Research Innovation Project for Postgraduate Students(2020YJSB150)the Ph.D.Can-didate Research Innovation Fund of NKU School of Materials Sci-ence and Engineering to H.-L.X.
文摘Two isomers of a sandwich-type anion [Ge_(9)-In-Ge_(9)]^(5–) were synthesized by controlling the chelating agents (2,2,2-crypt/18-C-6). Further reactions with early/late transition metal complexes, Mo(CO)_(6) and Ni(COD)_(2), respectively, yielded two new types of inorganic sandwich derivatives: a half-sandwich cluster [Ge_(9)-In-Mo(CO)_(5)]^(3–) with a low-valence In(I) center and an unsymmetrical sandwich-type cluster {[(Ni@Ge_(9))In(Ni_(0.648)@Ge_(9))]}^(5–) due to the insertion of Ni atoms, respectively. The isolation of these new derivatives demonstrates the reactivity of sandwich-type [Ge_(9)-In-Ge_(9)]^(5–) acting as the precursor, which provides some enlightenment for constructing new inorganic sandwich compounds.
基金the Anhui Provincial Department of Education(No.KJ2021A1125)the National Natural Science Foundation of China(No.12374390)+1 种基金Ningbo 3315 Innovative Teams Program(No.2019A-14-C)the member of Youth Innovation Promotion Association Foundation of CAS,China(No.2023310).
文摘Designing catalysts with highly active,selectivity,and stability for electrocatalytic CO_(2)to formate is currently a severe challenge.Herein,we developed an electronic structure engineering on carbon nano frameworks embedded with nitrogen and sulfur asymmetrically dual-coordinated indium active sites toward the efficient electrocatalytic CO_(2)reduction reaction.As expected,atomically dispersed In-based catalysts with In-S_(1)N_(3)atomic interface with asymmetrically coordinated exhibited high efficiency for CO_(2)reduction reaction(CO_(2)RR)to formate.It achieved a maximum Faradaic efficiency(FE)of 94.3%towards formate generation at−0.8 V vs.reversible hydrogen electrode(RHE),outperforming that of catalysts with In-S2N2 and In-N4 atomic interface.And at a potential of−1.10 V vs.RHE,In-S_(1)N_(3)achieves an impressive Faradaic efficiency of 93.7%in flow cell.The catalytic performance of In-S_(1)N_(3)sites was confirmed to be enhanced through in-situ X-ray absorption near-edge structure(XANES)measurements under electrochemical conditions.Our discovery provides the guidance for performance regulation of main group metal catalysts toward CO_(2)RR at atomic scale.
文摘Thousands of landslide data being taken as the nation wide statistics of sampling and the two state variables of landslide being processed with two methods described in the references, the main types of lithological groups of landslides in China have been sieved and selected.On the other hand, through the displacement table of Pascal Yanghui triangle used in the information encoding theory, the mark weight of sampling can be calculated and the main lithological groups which have close relationship with landslide occurrence can be gained.In comparison with the both results, the characteristics of main sliding lithological groups are determinated, and the main distribution regions of landslides can be prognosticated.
基金Supported by the High-Tech Research and Development Program of China(No.2006AA02Z291)the National Natural Science Foundation of China(No.50673105)
文摘A main-chain liquid crystalline ionomer（MLCI） containing sulfonic group was synthesized by an interfacial condensation reaction.The MLCI was blended with polybutylene terephthalate（PBT） and polypropylene（PP）.MLCI interacted with both the dispersed（PP） phase and the matrix（PBT） phase to modify the interfacial interaction of PBT and PP.Differential scanning calorimetry（DSC）,scanning electron microscopy（SEM） and FTIR imaging system analysis demonstrated the significance of interfacial interaction in the polymer blends.MLCI brought about good adhesion at the interfacial,which reduced the disperse phase size and enabled a fine PP phase at matrix.The mechanical properties of the ternary blends were improved when a proper amount of MLCI was added.This was attributed to enhanced adhesion at the interface,which invoked better mechanical properties in the blends.
基金the National Natural Science Foundation of China(No.21901039)the Natural Science Foundation of Jiangsu Province(No.BK20190327)。
文摘Carboranes are a class of polyhedral boron-carbon molecular clusters,they can serve as versatile ligands in stabilizing low-valent main group element compounds,due to their exceptionally thermal and chemical stabilities,easy modifications at the cage carbon vertices,as well as large spherical steric effects.These carborane-based ligands provide interesting opportunities for the synthesis of low-valent main group element compounds with novel structure and reactivity,which indeed enrich the chemistry of low-valent element main group compounds.This review summarizes the recent advances in the chemistry of lowvalent group 13 and group 14 element compounds supported by carborane-based ligands.Achievements and perspectives in this new and flourishing field are discussed in this review.
