Currently,the electrocatalytic two-electron oxygen reduction reaction for the production of H_(2)O_(2) presents a promising alternative to the energy-intensive anthraquinone process.Enhancing the selectivity and activ...Currently,the electrocatalytic two-electron oxygen reduction reaction for the production of H_(2)O_(2) presents a promising alternative to the energy-intensive anthraquinone process.Enhancing the selectivity and activity of the catalyst is crucial for achieving efficient electrosynthesis of H_(2)O_(2).Transition metal compound catalysts are considered ideal electrocatalysts due to their advantages,including simple preparation,low cost,diverse crystal structures,abundant availability,environmental friendliness,and the synergistic effects between coupled metals.This paper systematically reviews the latest research advancements regarding transition metal compounds used in oxygen reduction reactions to generate H_(2)O_(2).It begins by elaborating on the fundamental concepts related to oxygen reduction reactions and subsequently discusses various methods for regulating transition metal compound catalysts,including element doping,defect generation,heterogeneous structure construction,crystal design,and polycrystalline transformation.The activities,selectivity,and stability of different transition metal compounds in the electrocatalytic synthesis of H_(2)O_(2) are summarized,and the future development directions for transition metal compound catalysts are explored,providing valuable insights for the large-scale and efficient electrosynthesis of H_(2)O_(2) in the future.展开更多
During the oxygen evolution reaction(OER),reconstruction of transition metal sulfides(TMSs)is inevitable.However,the lack of a clear theoretical understanding of this process has impeded the development of effective r...During the oxygen evolution reaction(OER),reconstruction of transition metal sulfides(TMSs)is inevitable.However,the lack of a clear theoretical understanding of this process has impeded the development of effective reconstruction regulation strategies.In this study,we first explored the reconstruction mechanism of CoS_(2)during OER from the perspective of electronic structure and identified two possible pathways:the OH-assisted mechanism and the O-assisted mechanism.Further verification showed that these mechanisms are universally applicable to other TMSs(e.g.,FeS_(2)).Based on the reconstruction mechanism,we investigated the basic reasons for the influence of various regulation strategies,such as vacancy modification and facet engineering,on the reconstruction ability.This verified that the method of analyzing the change in the reconstruction ability of catalysts based on the reconstruction mechanism has a high degree of applicability.Importantly,we proposed a core regulation strategy:the coordination symmetry regulation strategy.Specifically,by breaking the symmetry of the surface coordination environment of TMSs(such as introducing heteroatom doping or strain),the reconstruction process will be facilitated.Our findings provide a comprehensive mechanistic explanation for the reconstruction of TMS catalysts and offer a new idea for the rational design of OER catalysts with controllable reconstruction capacity.展开更多
Zinc-air batteries(ZABs)are widely studied because of their high theoretical energy density,high battery voltage,environmental protection,and low price.However,the slow kinetics of oxygen reduction reaction(ORR)and ox...Zinc-air batteries(ZABs)are widely studied because of their high theoretical energy density,high battery voltage,environmental protection,and low price.However,the slow kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)on the air electrode limits the further application of ZABs,so that how to develop a cheap,efficient,and stable catalyst with bifunctional catalytic activity is the key to solving the development of ZABs.Transition metal compounds are widely used as cathode materials for ZABs due to their low cost,high electrocatalytic activity,and stable structure.This review summarizes the research progress of transition metal compounds as bifunctional catalysts for ZABs.The development history,operation principle,and mechanism of ORR and OER reactions are introduced first.The application and development of transition metal compounds as bifunctional catalysts for ZABs in recent years are systematically introduced,including transition metal oxides(TMOs),transition metal nitrides(TMNs),transition metal sulfides(TMSs),transition metal carbides(TMCs),transition metal phosphates(TMPs),and others.In addition,the shortcomings of transition metal compounds as bifunctional catalysts for ZABs were summarized and reasonable design strategies and improvement measures were put forward,aiming at providing a reference for the design and construction of high-performance ZABs cathode materials.Finally,the challenges and future in this field are discussed and prospected.展开更多
The catalytic effects of the organic compounds of iron,tin and manganese on the degradation of low density polyethylene (LDPE) at compost temperature are discussed.A series of samples were aged in a simulating compost...The catalytic effects of the organic compounds of iron,tin and manganese on the degradation of low density polyethylene (LDPE) at compost temperature are discussed.A series of samples were aged in a simulating compost environment.The mechanical properties,viscosity average molecular weight (M η) of PE and hydroperoxide (POOH) concentration in the samples were measured.FT IR and DSC were also applied to characterize some samples.It was shown that the above mentioned metallic organic compounds can catalyze the degradation of LDPE efficiently.After 2 months aging,all samples with catalysts became fragile and the M η of the material decreased dramatically.Furthermore,the concentration of carbonyl and the degree of crystallinity of the material increased with the aging time.展开更多
An experiment facility has been set up for the study of metal cluster compounds in our laboratory, which consists of a nano-electrospray ionization source, an ion transmission and focus system, and a reflectron time-o...An experiment facility has been set up for the study of metal cluster compounds in our laboratory, which consists of a nano-electrospray ionization source, an ion transmission and focus system, and a reflectron time-of-fight mass spectrometer. Taking advantage of the nano-electrospray ionization source, polyvalent ions are usually produced in the ＂ionization＂ process and the obtained mass resolution of the equipment is over 8000. The molecular ion peaks of metal cluster compounds [Au20（PPhpy2）10Cl2]（SbF6）4, where PPhpy2=bis（2- pyridyl）phenylphosphine, and [AuaAg2（C）L6]（BF4）4, where L=2-（diphenylphosphino）-5- methylpyridine, are distinguished in the respective mass spectrum, accompanied by some fragment ion peaks. In addition, the mass-to-charge ratios of the parent ions are determi- nated. Preliminary results suggest that the device is a powerful tool for the study of metal cluster compounds. It turns out that the information obtained by the instrumentation serves as an essential supplement to single crystal X-ray diffraction for structure characterization of metal cluster compounds.展开更多
Reconstruction during the oxygen evolution reaction(OER)significantly transforms the geometric structure of transition metal compounds,leading to enhanced catalytic performance.However,the resulting structural disorde...Reconstruction during the oxygen evolution reaction(OER)significantly transforms the geometric structure of transition metal compounds,leading to enhanced catalytic performance.However,the resulting structural disorder complicates the development of accurate theoretical models.In this study,CoS2 is used as a model system to establish a framework for rationally modeling reconstructed OER catalysts based on density functional theory(DFT).In the reconstruction process,sulfur atoms are likely to be substituted by oxygen atoms,leading to the formation of the CoOOH phase.Based on the difference in reconstruction degree,we constructed three types of models:doping,heterostructure,and fully reconstructed,representing the reconstruction degree from minimal to full phase transition,respectively.Fully reconstructed models,which account for strain and vacancy effects,effectively simulate the unique coordination environments of reconstructed catalysts.Model e-CoOOH achieves a theoretical overpotential of 0.38 V,outperforming pristine CoOOH(0.56 V),demonstrating that the unique structural features resulting from reconstruction improve OER performance.The doping model and the heterostructure model are helpful to explain the electronic structure and performance transformation of the reconstruction process.This work provides a rational theoretical modeling approach,which is conducive to improving the reliability of the theoretical OER performance of the reconstructed catalyst.展开更多
The carbyne compound [Br(CO)_2(Py)_2Mo(≡CC_6H_5)] (Py=pyridine) (1a) reacts with Co_2 (CO)_8, Fe_2(CO)_9 and Mn_2 (CO)_(10) to give tetrahedral tri-metal cluster compounds Co_2Mo(μ_3-CC_6H_5)Br(CO)_8(Py)_2 (2), Fe_2...The carbyne compound [Br(CO)_2(Py)_2Mo(≡CC_6H_5)] (Py=pyridine) (1a) reacts with Co_2 (CO)_8, Fe_2(CO)_9 and Mn_2 (CO)_(10) to give tetrahedral tri-metal cluster compounds Co_2Mo(μ_3-CC_6H_5)Br(CO)_8(Py)_2 (2), Fe_2Mo(μ_3-CC_6H_5) Br(CO)_9(Py)_2 (3) and Mn_2Mo(μ_3-CC_6H_5)Br(CO)_(10) (Py)_2 (4) respectively. Tri-metal cluster compound Co_2Mo(μ_3-CC_6H_5)Br(CO)_8-(bipy) (bipy=α,α'dipyridyl) (5) is prepared in a similar reaction sequence from [Br(CO)_2(bipy)Mo(≡CC_6H_5)] (1b) and Co_2(CO)_8. IR, ~1H and ^(13)C NMR spectral data of these compounds are reported and discussed. The crystal structure of compound (5) has been determined by X-ray diffraction.展开更多
In recent years JSC "Krastsvetmet" has successfully developed the production of chemically pure compounds of precious metals.Currently methods have been developed and facilities have been provided for indust...In recent years JSC "Krastsvetmet" has successfully developed the production of chemically pure compounds of precious metals.Currently methods have been developed and facilities have been provided for industrial production of the following platinum metals compounds:Rhodium(Ⅲ) chloride hydrate,rhodium(Ⅲ) chloride solution,rhodium(Ⅲ) nitrate solution,rhodium(Ⅲ) iodide,rhodium(Ⅲ) sulfate,hydrated rhodium(Ⅲ) oxide,ammonium hexachlororodiate,rhodium(Ⅲ) phosphate solution,rhodium electrolytes;Iridium(Ⅳ) chloride hydrate,iridium(Ⅲ) chloride hydrate,ammonium hexachloroiridate(Ⅳ),hexa chloriridium acid solution,hexachloriridium crystalline acid;Ruthenium(Ⅲ) chloride hydrate,ruthenium(Ⅳ) hydroxide chloride,ruthenium(Ⅳ) hydroxide chloride solution,ammonium hexachlororuthenate,ruthenium(Ⅲ) chloride solution,potassium,diaquaoctachloronitrido diruthenate.The quality of the production meets the requirements of Russian and foreign consumers.展开更多
In this study,the electronic transition properties and structural analysis of the metal complexes(Ni(Ⅱ),Co(Ⅱ),Cu(Ⅱ)and Mn(Ⅱ))of three different polymer ligands were performed by using XRF and X-ray diffraction(XRD...In this study,the electronic transition properties and structural analysis of the metal complexes(Ni(Ⅱ),Co(Ⅱ),Cu(Ⅱ)and Mn(Ⅱ))of three different polymer ligands were performed by using XRF and X-ray diffraction(XRD)techniques,respectively.The structural analysis of the polymers and their complexes were performed by XRD technique and some of the polymers were found to be in the face-centred cubic(fcc)structure.In addition,the values of the present K X-ray intensity ratios are significantly greater than the values reported in literature.展开更多
Aromatic bond including metallic atom (Ni) is investigated by EHMO calculation.The NMR spectra and the mechanism for hydrolysis are discussed on the ground of results of computation.
The spontaneous magnetic transitions and corresponding magnetoelastic properties of intermetallic compounds RMn2Ge2（R=Gd, Tb and Dy） were investigated by using the X-ray diffraction method and magnetic measurement. ...The spontaneous magnetic transitions and corresponding magnetoelastic properties of intermetallic compounds RMn2Ge2（R=Gd, Tb and Dy） were investigated by using the X-ray diffraction method and magnetic measurement. The results showed that the compounds experience two magnetic transitions, namely the second-order paramagnetic to antiferromagnetic transition at temperature TN（TN=368, 423 and 443 K for Gd Mn2 Ge2, Tb Mn2 Ge2 and Dy Mn2 Ge2, respectively） and the first-order antiferromagnetic-ferrimagnetic transition at temperature Tt（Tt=96, 80 and 40 K for Gd Mn2 Ge2, Tb Mn2 Ge2 and Dy Mn2 Ge2, respectively） as the temperature decreases. The temperature dependence of the lattice constant a（T） displays a negative magnetoelastic anomaly at the second-order transition point TN and, at the first-order transition Tt, a increases abruptly for Gd Mn2 Ge2 and Tb Mn2 Ge2, Da/a about 10^（-3）. Nevertheless, the lattice constant c almost does not change at these transition points indicating that such magnetoelastic anomalies are mainly contributed by the Mn-sublattice. The transitions of the magnetoelastic properties are also evidenced on the temperature dependence of magnetic susceptibility χ. The first-order transition behavior at Tt is explained by the Kittel mode of exchange inversion.展开更多
The transmetallation reaction of 4 Schiff base type arylmercury compounds with metallic tin has been carried out in refluxing xylene.It was found that the reaction proceeds in the same manner as that of chloro[2-(phen...The transmetallation reaction of 4 Schiff base type arylmercury compounds with metallic tin has been carried out in refluxing xylene.It was found that the reaction proceeds in the same manner as that of chloro[2-(phenylazo)phenyl]mercury(Ⅱ) to give dichlorobisaryltin(Ⅳ).The ~1H NMR spectra of the products provide evidence for the presence of N→Sn intramolecular coordination.The formation of dichlorobisaryltin(Ⅳ)as a unique product probably arises from the N→Sn intramolecular coordination which results in the increasing of the stability of the molecule.展开更多
Some new Schiff bases were synthesized by the condensation of equimolar quantities of salicylaldehyde and 2-amino-5-phenylazo-pyridine or its derivatives in dry benzene(1):Metal complexes of the type ML_2and M'L_3...Some new Schiff bases were synthesized by the condensation of equimolar quantities of salicylaldehyde and 2-amino-5-phenylazo-pyridine or its derivatives in dry benzene(1):Metal complexes of the type ML_2and M'L_3 where M=Cu^(2+),Co^(2+),Ni^(2+),Mn^(2+)Pd^(2+),M'=Fe^(3+)and L=different newly synthesized monobasic Schiff bases were prepared in absolute ethanolic medium(2)and characterized by elementary analysis,conductance measurements,infrared spectra,electronic spectra,magnetic moments studies.展开更多
Engineering transition metal compounds(TMCs)catalysts with excellent adsorption-catalytic ability has been one of the most effec-tive strategies to accelerate the redox kinetics of sulfur cathodes.Herein,this review f...Engineering transition metal compounds(TMCs)catalysts with excellent adsorption-catalytic ability has been one of the most effec-tive strategies to accelerate the redox kinetics of sulfur cathodes.Herein,this review focuses on engineering TMCs catalysts by cation doping/anion doping/dual doping,bimetallic/bi-anionic TMCs,and TMCs-based heterostructure composites.It is obvious that introducing cations/anions to TMCs or constructing heterostructure can boost adsorption-catalytic capacity by regulating the electronic structure including energy band,d/p-band center,electron filling,and valence state.Moreover,the elec-tronic structure of doped/dual-ionic TMCs are adjusted by inducing ions with different electronegativity,electron filling,and ion radius,resulting in electron redistribution,bonds reconstruction,induced vacancies due to the electronic interaction and changed crystal structure such as lat-tice spacing and lattice distortion.Different from the aforementioned two strategies,heterostructures are constructed by two types of TMCs with different Fermi energy levels,which causes built-in electric field and electrons transfer through the interface,and induces electron redistribution and arranged local atoms to regulate the electronic structure.Additionally,the lacking studies of the three strategies to comprehensively regulate electronic structure for improving catalytic performance are pointed out.It is believed that this review can guide the design of advanced TMCs catalysts for boosting redox of lithium sulfur batteries.展开更多
The effects of substitution of AI for Co on magnetic and magnetocaloric properties of MnCo1-xAlxGe （x=0.00, 0.03, 0.05, 0.08, 0.10, 0.13, 0.15, and 0.20） compounds have been investigated by X-ray diffraction （XRD）...The effects of substitution of AI for Co on magnetic and magnetocaloric properties of MnCo1-xAlxGe （x=0.00, 0.03, 0.05, 0.08, 0.10, 0.13, 0.15, and 0.20） compounds have been investigated by X-ray diffraction （XRD） and magnetization measurements. XRD exhibits that MnCo1-xAlxGe compounds crystallize in the orthorhombic TiNiSi-type structure for x〈0.03 and in the hexagonal Ni2In-type crystal structure for x〉0.03. Magnetic measurements show that the Curie temperature can be tuned between 286 and 347 K by changing the Co/Al ratio. The maximum magnetic entropy change determined from the isothermal magnetization measurement by Maxwell relation reaches 1.52 J/（kgK） for x=0.08 in a field change from 0 to 1.5 T around 310 K.展开更多
Supercapacitors(SCs)have remarkable energy storage capabilities and have garnered considerable interest due to their superior power densities and ultra-long cycling characteristics.However,their comparatively low ener...Supercapacitors(SCs)have remarkable energy storage capabilities and have garnered considerable interest due to their superior power densities and ultra-long cycling characteristics.However,their comparatively low energy density limits their extensive application in large-scale commercial applications.Electrode materials directly affect the performance of SCs.Thus,the development of cutting-edge electrode materials and modification of their morphological and structural properties are vital for advancing the performance of SCs.Transition metal compounds have a high specific capacity and good cycling durability,making them the most promising electrode active materials for high-energy density SCs.Nevertheless,their inadequate conductivity,unfavorable ion diffusion rates,substantial volume expansion and phase transitions during charging and discharging are obstacles to their stable and efficient integration into SCs.To address these challenges,this study provides a comprehensive summary of the current advancements in transition metal nanomaterials as electrode materials for SCs,an overview of the current research status,and the prevailing challenges.Furthermore,this study highlights synthetic techniques and management strategies for electrode materials derived from transition metal compounds,targeting the resolution of the aforementioned challenges.Finally,a concise discussion is provided on the future directions of SC development,with an emphasis on the utilization of transition metal compound electrode materials.展开更多
Bimetallic catalysts usually exhibit better performance than monometallic catalysts due to synergistic effect.However,there is a lack of exploring the synergistic effect on catalytic performance caused by the introduc...Bimetallic catalysts usually exhibit better performance than monometallic catalysts due to synergistic effect.However,there is a lack of exploring the synergistic effect on catalytic performance caused by the introduction of inactive metal ion.In this work,we design a molecular model system that can precisely regulate the metal site number and catalytic property.When these molecular metal compounds are used as homogeneous catalysts for photocatalytic CO_(2)reduction,the dinuclear heterometallic CuNi-L2shows the highest CO_(2)-to-CO conversion,which is 2.1 and 3.0 times higher than that of dinuclear homometallic Ni2-L2and mononuclear Ni-L1.Density functional theory calculations demonstrate that,in CuNi-L2,the introduction of inactive CuⅡis easier to promote the photo-generated electrons transferring to the coupled active NiⅡsite to achieve the highest activity.In addition,this work also provides insights to design and construct more efficient bimetallic catalysts in future.展开更多
Urea oxidation reaction(UOR)is an auxiliary water electrolysis hydrogen production technology developed in recent years to replace oxygen evolution reaction and reduce energy consumption,which can produce hydrogen mor...Urea oxidation reaction(UOR)is an auxiliary water electrolysis hydrogen production technology developed in recent years to replace oxygen evolution reaction and reduce energy consumption,which can produce hydrogen more efficiently by low theoretical potential,reduce the average cost of electrochemical hydrogen production,and is a frontier research hotspot for renewable hydrogen energy.Two-dimensional(2D)nanomaterials as electrocatalysts have many favorable potential,such as it can effectively reduce the resistivity of materials and increase the specific surface area with certainty.This paper reviews the application of 2D materials in UOR in alkaline electrolytes.And a cross-sectional comparison of various material performance data including overpotential,Tafel slope,electrochemical active surface area(ECSA)and it stability test was conducted,which could illustrate the differences between materials composed of different elements.In addition,the main challenges hindering the progress of research on 2D materials in urea electrocatalysis processes and promising materials in this field in future are summarized and prospected.It is believed that this review will contribute to designing and analyzing highperformance 2D urea electrocatalysts for water splitting.展开更多
The development of inexpensive and efficient electrocatalysts is key to commercializing energy-related electrocatalytic techniques such as water electrolyzers and metal-air batteries.In particular,novel oxygen evoluti...The development of inexpensive and efficient electrocatalysts is key to commercializing energy-related electrocatalytic techniques such as water electrolyzers and metal-air batteries.In particular,novel oxygen evolution reaction(OER)pre-catalysts,such as transition metal chalcogenides(TMCs)and phosphides(TMPs),have evolved in recent years from traditional stable OER electrocatalysts,which show superior OER electrocatalytic performance compared with transition metal oxides(TMOs)or(oxy)hydroxides(TMOHs).In this feature article,we summarize recent advances in the development of TMCand TMP-based OER electrocatalysts,as well as approaches to improve the OER performance in terms of morphology,structure,composition,surface engineering,lattice-strained and in-situ transformation in the electrolysis process.In particular,the electrochemical stability of TMCs and TMPs in alkaline electrolytes and the evolution of morphology,structure and composition under OER conditions are discussed.In the last section,we discuss the challenges that need to be addressed in this specific area of research and the implications for further research.展开更多
As one of the important aspects of upgrading coal tar,the ultra-deep removal of metal ions via the complexation method was investigated by screening four complexing agents and performing density functional theory(DFT)...As one of the important aspects of upgrading coal tar,the ultra-deep removal of metal ions via the complexation method was investigated by screening four complexing agents and performing density functional theory(DFT)simulations.Analysis of the compositions and contents of the metallic compounds in the coal tar revealed that the main components were iron and calcium naphthenates.Direct filtration reduced the mechanical impurity content from 0.24%to 0.0752%,indicating that most of the large particles could be easily removed.Among the four complexing agents,namely,acetic acid,oxalic acid,citric acid,and ethylenediaminetetraacetic acid,oxalic acid exhibited the best demetallization performance.The DFT simulations suggested that the high performance of oxalic acid originated from its 1:1 coordination mode,rigid dicarboxyl structure,and greater binding energy.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52364041)the Yunnan Province(Grant No.202401AV070011).
文摘Currently,the electrocatalytic two-electron oxygen reduction reaction for the production of H_(2)O_(2) presents a promising alternative to the energy-intensive anthraquinone process.Enhancing the selectivity and activity of the catalyst is crucial for achieving efficient electrosynthesis of H_(2)O_(2).Transition metal compound catalysts are considered ideal electrocatalysts due to their advantages,including simple preparation,low cost,diverse crystal structures,abundant availability,environmental friendliness,and the synergistic effects between coupled metals.This paper systematically reviews the latest research advancements regarding transition metal compounds used in oxygen reduction reactions to generate H_(2)O_(2).It begins by elaborating on the fundamental concepts related to oxygen reduction reactions and subsequently discusses various methods for regulating transition metal compound catalysts,including element doping,defect generation,heterogeneous structure construction,crystal design,and polycrystalline transformation.The activities,selectivity,and stability of different transition metal compounds in the electrocatalytic synthesis of H_(2)O_(2) are summarized,and the future development directions for transition metal compound catalysts are explored,providing valuable insights for the large-scale and efficient electrosynthesis of H_(2)O_(2) in the future.
基金supported by the National Key Research and Development program(2022YFA1504000)the National Natural Science Foundation of China(22302101)+4 种基金the Fundamental Research Funds for the Central Universities(63185015)the Shenzhen Science and Technology Program(JCYJ20210324121002007,JCYJ20230807151503007)the Yunnan Provincial Science and Technology Project at Southwest United Graduate School(202402AO370001)the China Postdoctoral Science Foundation(2022M721699)the Guangdong Basic and Applied Basic Research Foundation(2024A1515010347).
文摘During the oxygen evolution reaction(OER),reconstruction of transition metal sulfides(TMSs)is inevitable.However,the lack of a clear theoretical understanding of this process has impeded the development of effective reconstruction regulation strategies.In this study,we first explored the reconstruction mechanism of CoS_(2)during OER from the perspective of electronic structure and identified two possible pathways:the OH-assisted mechanism and the O-assisted mechanism.Further verification showed that these mechanisms are universally applicable to other TMSs(e.g.,FeS_(2)).Based on the reconstruction mechanism,we investigated the basic reasons for the influence of various regulation strategies,such as vacancy modification and facet engineering,on the reconstruction ability.This verified that the method of analyzing the change in the reconstruction ability of catalysts based on the reconstruction mechanism has a high degree of applicability.Importantly,we proposed a core regulation strategy:the coordination symmetry regulation strategy.Specifically,by breaking the symmetry of the surface coordination environment of TMSs(such as introducing heteroatom doping or strain),the reconstruction process will be facilitated.Our findings provide a comprehensive mechanistic explanation for the reconstruction of TMS catalysts and offer a new idea for the rational design of OER catalysts with controllable reconstruction capacity.
基金the German Research Foundation(DFG:LE 2249/15-1)the Sino-German Center for Research Promotion(GZ1579)Y.R.and C.F.X.would like to appreciate the support from the China Scholarship Council(Nos.202207030010 and 20210637004).
文摘Zinc-air batteries(ZABs)are widely studied because of their high theoretical energy density,high battery voltage,environmental protection,and low price.However,the slow kinetics of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)on the air electrode limits the further application of ZABs,so that how to develop a cheap,efficient,and stable catalyst with bifunctional catalytic activity is the key to solving the development of ZABs.Transition metal compounds are widely used as cathode materials for ZABs due to their low cost,high electrocatalytic activity,and stable structure.This review summarizes the research progress of transition metal compounds as bifunctional catalysts for ZABs.The development history,operation principle,and mechanism of ORR and OER reactions are introduced first.The application and development of transition metal compounds as bifunctional catalysts for ZABs in recent years are systematically introduced,including transition metal oxides(TMOs),transition metal nitrides(TMNs),transition metal sulfides(TMSs),transition metal carbides(TMCs),transition metal phosphates(TMPs),and others.In addition,the shortcomings of transition metal compounds as bifunctional catalysts for ZABs were summarized and reasonable design strategies and improvement measures were put forward,aiming at providing a reference for the design and construction of high-performance ZABs cathode materials.Finally,the challenges and future in this field are discussed and prospected.
文摘The catalytic effects of the organic compounds of iron,tin and manganese on the degradation of low density polyethylene (LDPE) at compost temperature are discussed.A series of samples were aged in a simulating compost environment.The mechanical properties,viscosity average molecular weight (M η) of PE and hydroperoxide (POOH) concentration in the samples were measured.FT IR and DSC were also applied to characterize some samples.It was shown that the above mentioned metallic organic compounds can catalyze the degradation of LDPE efficiently.After 2 months aging,all samples with catalysts became fragile and the M η of the material decreased dramatically.Furthermore,the concentration of carbonyl and the degree of crystallinity of the material increased with the aging time.
文摘An experiment facility has been set up for the study of metal cluster compounds in our laboratory, which consists of a nano-electrospray ionization source, an ion transmission and focus system, and a reflectron time-of-fight mass spectrometer. Taking advantage of the nano-electrospray ionization source, polyvalent ions are usually produced in the ＂ionization＂ process and the obtained mass resolution of the equipment is over 8000. The molecular ion peaks of metal cluster compounds [Au20（PPhpy2）10Cl2]（SbF6）4, where PPhpy2=bis（2- pyridyl）phenylphosphine, and [AuaAg2（C）L6]（BF4）4, where L=2-（diphenylphosphino）-5- methylpyridine, are distinguished in the respective mass spectrum, accompanied by some fragment ion peaks. In addition, the mass-to-charge ratios of the parent ions are determi- nated. Preliminary results suggest that the device is a powerful tool for the study of metal cluster compounds. It turns out that the information obtained by the instrumentation serves as an essential supplement to single crystal X-ray diffraction for structure characterization of metal cluster compounds.
基金supported by the National Key Research and Development program(2022YFA1504000)the National Natural Science Foundation of China(22302101)+4 种基金the Fundamental Research Funds for the Central Universities(63185015)Shenzhen Science and Technology Program(JCYJ20210324121002007,JCYJ20230807151503007)Yunnan Provincial Science and Technology Project at Southwest United Graduate School(202402AO370001)China Postdoctoral Science Foundation(2022M721699)Guangdong Basic and Applied Basic Research Foundation(2024A1515010347).
文摘Reconstruction during the oxygen evolution reaction(OER)significantly transforms the geometric structure of transition metal compounds,leading to enhanced catalytic performance.However,the resulting structural disorder complicates the development of accurate theoretical models.In this study,CoS2 is used as a model system to establish a framework for rationally modeling reconstructed OER catalysts based on density functional theory(DFT).In the reconstruction process,sulfur atoms are likely to be substituted by oxygen atoms,leading to the formation of the CoOOH phase.Based on the difference in reconstruction degree,we constructed three types of models:doping,heterostructure,and fully reconstructed,representing the reconstruction degree from minimal to full phase transition,respectively.Fully reconstructed models,which account for strain and vacancy effects,effectively simulate the unique coordination environments of reconstructed catalysts.Model e-CoOOH achieves a theoretical overpotential of 0.38 V,outperforming pristine CoOOH(0.56 V),demonstrating that the unique structural features resulting from reconstruction improve OER performance.The doping model and the heterostructure model are helpful to explain the electronic structure and performance transformation of the reconstruction process.This work provides a rational theoretical modeling approach,which is conducive to improving the reliability of the theoretical OER performance of the reconstructed catalyst.
文摘The carbyne compound [Br(CO)_2(Py)_2Mo(≡CC_6H_5)] (Py=pyridine) (1a) reacts with Co_2 (CO)_8, Fe_2(CO)_9 and Mn_2 (CO)_(10) to give tetrahedral tri-metal cluster compounds Co_2Mo(μ_3-CC_6H_5)Br(CO)_8(Py)_2 (2), Fe_2Mo(μ_3-CC_6H_5) Br(CO)_9(Py)_2 (3) and Mn_2Mo(μ_3-CC_6H_5)Br(CO)_(10) (Py)_2 (4) respectively. Tri-metal cluster compound Co_2Mo(μ_3-CC_6H_5)Br(CO)_8-(bipy) (bipy=α,α'dipyridyl) (5) is prepared in a similar reaction sequence from [Br(CO)_2(bipy)Mo(≡CC_6H_5)] (1b) and Co_2(CO)_8. IR, ~1H and ^(13)C NMR spectral data of these compounds are reported and discussed. The crystal structure of compound (5) has been determined by X-ray diffraction.
文摘In recent years JSC "Krastsvetmet" has successfully developed the production of chemically pure compounds of precious metals.Currently methods have been developed and facilities have been provided for industrial production of the following platinum metals compounds:Rhodium(Ⅲ) chloride hydrate,rhodium(Ⅲ) chloride solution,rhodium(Ⅲ) nitrate solution,rhodium(Ⅲ) iodide,rhodium(Ⅲ) sulfate,hydrated rhodium(Ⅲ) oxide,ammonium hexachlororodiate,rhodium(Ⅲ) phosphate solution,rhodium electrolytes;Iridium(Ⅳ) chloride hydrate,iridium(Ⅲ) chloride hydrate,ammonium hexachloroiridate(Ⅳ),hexa chloriridium acid solution,hexachloriridium crystalline acid;Ruthenium(Ⅲ) chloride hydrate,ruthenium(Ⅳ) hydroxide chloride,ruthenium(Ⅳ) hydroxide chloride solution,ammonium hexachlororuthenate,ruthenium(Ⅲ) chloride solution,potassium,diaquaoctachloronitrido diruthenate.The quality of the production meets the requirements of Russian and foreign consumers.
基金Scientific Research Fund of Kahramanmaras Sutcu Imam University,Turkey(2012/3-7YLS)
文摘In this study,the electronic transition properties and structural analysis of the metal complexes(Ni(Ⅱ),Co(Ⅱ),Cu(Ⅱ)and Mn(Ⅱ))of three different polymer ligands were performed by using XRF and X-ray diffraction(XRD)techniques,respectively.The structural analysis of the polymers and their complexes were performed by XRD technique and some of the polymers were found to be in the face-centred cubic(fcc)structure.In addition,the values of the present K X-ray intensity ratios are significantly greater than the values reported in literature.
文摘Aromatic bond including metallic atom (Ni) is investigated by EHMO calculation.The NMR spectra and the mechanism for hydrolysis are discussed on the ground of results of computation.
基金Funded by the National Natural Science Foundation of China(Nos.11547186,11604091)the Natural Science Foundation of Hunan Province(No.2018JJ2019)the Research Foundation of Education Bureau of Hunan Province,China(No.16B048)
文摘The spontaneous magnetic transitions and corresponding magnetoelastic properties of intermetallic compounds RMn2Ge2（R=Gd, Tb and Dy） were investigated by using the X-ray diffraction method and magnetic measurement. The results showed that the compounds experience two magnetic transitions, namely the second-order paramagnetic to antiferromagnetic transition at temperature TN（TN=368, 423 and 443 K for Gd Mn2 Ge2, Tb Mn2 Ge2 and Dy Mn2 Ge2, respectively） and the first-order antiferromagnetic-ferrimagnetic transition at temperature Tt（Tt=96, 80 and 40 K for Gd Mn2 Ge2, Tb Mn2 Ge2 and Dy Mn2 Ge2, respectively） as the temperature decreases. The temperature dependence of the lattice constant a（T） displays a negative magnetoelastic anomaly at the second-order transition point TN and, at the first-order transition Tt, a increases abruptly for Gd Mn2 Ge2 and Tb Mn2 Ge2, Da/a about 10^（-3）. Nevertheless, the lattice constant c almost does not change at these transition points indicating that such magnetoelastic anomalies are mainly contributed by the Mn-sublattice. The transitions of the magnetoelastic properties are also evidenced on the temperature dependence of magnetic susceptibility χ. The first-order transition behavior at Tt is explained by the Kittel mode of exchange inversion.
文摘The transmetallation reaction of 4 Schiff base type arylmercury compounds with metallic tin has been carried out in refluxing xylene.It was found that the reaction proceeds in the same manner as that of chloro[2-(phenylazo)phenyl]mercury(Ⅱ) to give dichlorobisaryltin(Ⅳ).The ~1H NMR spectra of the products provide evidence for the presence of N→Sn intramolecular coordination.The formation of dichlorobisaryltin(Ⅳ)as a unique product probably arises from the N→Sn intramolecular coordination which results in the increasing of the stability of the molecule.
文摘Some new Schiff bases were synthesized by the condensation of equimolar quantities of salicylaldehyde and 2-amino-5-phenylazo-pyridine or its derivatives in dry benzene(1):Metal complexes of the type ML_2and M'L_3 where M=Cu^(2+),Co^(2+),Ni^(2+),Mn^(2+)Pd^(2+),M'=Fe^(3+)and L=different newly synthesized monobasic Schiff bases were prepared in absolute ethanolic medium(2)and characterized by elementary analysis,conductance measurements,infrared spectra,electronic spectra,magnetic moments studies.
基金The authors acknowledge funding from National Natural Science Foundation of China(52302307)Shaanxi Province(2023-ZDLGY-24,2023-JC-QN-0473)+2 种基金project funded by China Postdoctoral Science Foundation(2023MD734210)the Open Foundation of State Key Laboratory for Advanced Metals and Materials(2022-Z01)Shaanxi Provincial Department of Education industrialization project(21JC018).
文摘Engineering transition metal compounds(TMCs)catalysts with excellent adsorption-catalytic ability has been one of the most effec-tive strategies to accelerate the redox kinetics of sulfur cathodes.Herein,this review focuses on engineering TMCs catalysts by cation doping/anion doping/dual doping,bimetallic/bi-anionic TMCs,and TMCs-based heterostructure composites.It is obvious that introducing cations/anions to TMCs or constructing heterostructure can boost adsorption-catalytic capacity by regulating the electronic structure including energy band,d/p-band center,electron filling,and valence state.Moreover,the elec-tronic structure of doped/dual-ionic TMCs are adjusted by inducing ions with different electronegativity,electron filling,and ion radius,resulting in electron redistribution,bonds reconstruction,induced vacancies due to the electronic interaction and changed crystal structure such as lat-tice spacing and lattice distortion.Different from the aforementioned two strategies,heterostructures are constructed by two types of TMCs with different Fermi energy levels,which causes built-in electric field and electrons transfer through the interface,and induces electron redistribution and arranged local atoms to regulate the electronic structure.Additionally,the lacking studies of the three strategies to comprehensively regulate electronic structure for improving catalytic performance are pointed out.It is believed that this review can guide the design of advanced TMCs catalysts for boosting redox of lithium sulfur batteries.
基金supported by National Natural Foundation of China (No 50661004)partly sup-ported by the Scientific Program of Inner Mongolia Nor-mal University, China (No 2007002)
文摘The effects of substitution of AI for Co on magnetic and magnetocaloric properties of MnCo1-xAlxGe （x=0.00, 0.03, 0.05, 0.08, 0.10, 0.13, 0.15, and 0.20） compounds have been investigated by X-ray diffraction （XRD） and magnetization measurements. XRD exhibits that MnCo1-xAlxGe compounds crystallize in the orthorhombic TiNiSi-type structure for x〈0.03 and in the hexagonal Ni2In-type crystal structure for x〉0.03. Magnetic measurements show that the Curie temperature can be tuned between 286 and 347 K by changing the Co/Al ratio. The maximum magnetic entropy change determined from the isothermal magnetization measurement by Maxwell relation reaches 1.52 J/（kgK） for x=0.08 in a field change from 0 to 1.5 T around 310 K.
基金supported by the National Natural Science Foundation of China(No.22301151)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2022QN05024)+3 种基金the Fundamental Scientific Research Funds for Universities directly under Inner Mongolia Autonomous Region of China(Nos.JY20230097 and JY20220116)the Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region(No.NMGIRT2211)Inner Mongolia University of Technology Key Discipline Team Project of Materials Science(No.ZD202012)the Young Leading Talent of“Grassland Talents”Project of Inner Mongolia Autonomous Region(No.QNLJ012010)。
文摘Supercapacitors(SCs)have remarkable energy storage capabilities and have garnered considerable interest due to their superior power densities and ultra-long cycling characteristics.However,their comparatively low energy density limits their extensive application in large-scale commercial applications.Electrode materials directly affect the performance of SCs.Thus,the development of cutting-edge electrode materials and modification of their morphological and structural properties are vital for advancing the performance of SCs.Transition metal compounds have a high specific capacity and good cycling durability,making them the most promising electrode active materials for high-energy density SCs.Nevertheless,their inadequate conductivity,unfavorable ion diffusion rates,substantial volume expansion and phase transitions during charging and discharging are obstacles to their stable and efficient integration into SCs.To address these challenges,this study provides a comprehensive summary of the current advancements in transition metal nanomaterials as electrode materials for SCs,an overview of the current research status,and the prevailing challenges.Furthermore,this study highlights synthetic techniques and management strategies for electrode materials derived from transition metal compounds,targeting the resolution of the aforementioned challenges.Finally,a concise discussion is provided on the future directions of SC development,with an emphasis on the utilization of transition metal compound electrode materials.
基金financially supported by the National Natural Science Foundation of China(NSFC,Nos.92061101,21871141,21871142 and 22071109)Project funded by China Postdoctoral Science Foundation(No.2018M630572)。
文摘Bimetallic catalysts usually exhibit better performance than monometallic catalysts due to synergistic effect.However,there is a lack of exploring the synergistic effect on catalytic performance caused by the introduction of inactive metal ion.In this work,we design a molecular model system that can precisely regulate the metal site number and catalytic property.When these molecular metal compounds are used as homogeneous catalysts for photocatalytic CO_(2)reduction,the dinuclear heterometallic CuNi-L2shows the highest CO_(2)-to-CO conversion,which is 2.1 and 3.0 times higher than that of dinuclear homometallic Ni2-L2and mononuclear Ni-L1.Density functional theory calculations demonstrate that,in CuNi-L2,the introduction of inactive CuⅡis easier to promote the photo-generated electrons transferring to the coupled active NiⅡsite to achieve the highest activity.In addition,this work also provides insights to design and construct more efficient bimetallic catalysts in future.
基金financially supported by the National Key Research and Development Program of China(No.2020YFB1713500)the Major Science and Technology Projects of Henan Province(No.221100230200)+3 种基金Program for Innovative Research Team(in Science and Technology)in University of Henan Province(No.23IRTSTHN009)the Project of Science and Technology Department of Henan Province(Nos.232102241034 and 222102240074)the Natural Science Foundation of Suzhou University of Science and Technology(No.XKQ2020002)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.22KJB530009)。
文摘Urea oxidation reaction(UOR)is an auxiliary water electrolysis hydrogen production technology developed in recent years to replace oxygen evolution reaction and reduce energy consumption,which can produce hydrogen more efficiently by low theoretical potential,reduce the average cost of electrochemical hydrogen production,and is a frontier research hotspot for renewable hydrogen energy.Two-dimensional(2D)nanomaterials as electrocatalysts have many favorable potential,such as it can effectively reduce the resistivity of materials and increase the specific surface area with certainty.This paper reviews the application of 2D materials in UOR in alkaline electrolytes.And a cross-sectional comparison of various material performance data including overpotential,Tafel slope,electrochemical active surface area(ECSA)and it stability test was conducted,which could illustrate the differences between materials composed of different elements.In addition,the main challenges hindering the progress of research on 2D materials in urea electrocatalysis processes and promising materials in this field in future are summarized and prospected.It is believed that this review will contribute to designing and analyzing highperformance 2D urea electrocatalysts for water splitting.
基金supported by the National Natural Science Foundation of China (No.22179014)the China Postdoctoral Science Foundation (No.2022 M720593)+2 种基金the Scientific Research Foundation of Chongqing University of Technology (Nos.2022ZDZ011,2022PYZ026)the Youth Project of Science and Technology Research Program of Chongqing Municipal Education Commission (No.KJQN202201127)the Project of Natural Science Foundation of Chongqing (No.2022NSCQ-MSX1123)。
文摘The development of inexpensive and efficient electrocatalysts is key to commercializing energy-related electrocatalytic techniques such as water electrolyzers and metal-air batteries.In particular,novel oxygen evolution reaction(OER)pre-catalysts,such as transition metal chalcogenides(TMCs)and phosphides(TMPs),have evolved in recent years from traditional stable OER electrocatalysts,which show superior OER electrocatalytic performance compared with transition metal oxides(TMOs)or(oxy)hydroxides(TMOHs).In this feature article,we summarize recent advances in the development of TMCand TMP-based OER electrocatalysts,as well as approaches to improve the OER performance in terms of morphology,structure,composition,surface engineering,lattice-strained and in-situ transformation in the electrolysis process.In particular,the electrochemical stability of TMCs and TMPs in alkaline electrolytes and the evolution of morphology,structure and composition under OER conditions are discussed.In the last section,we discuss the challenges that need to be addressed in this specific area of research and the implications for further research.
基金the National Energy R&D Center of Petroleum Refining Technology(RIPP,SINOPEC)the National Natural Science Foundation of China(22078347)the Key Research and Development Program of Hebei Province,China(21373303D).
文摘As one of the important aspects of upgrading coal tar,the ultra-deep removal of metal ions via the complexation method was investigated by screening four complexing agents and performing density functional theory(DFT)simulations.Analysis of the compositions and contents of the metallic compounds in the coal tar revealed that the main components were iron and calcium naphthenates.Direct filtration reduced the mechanical impurity content from 0.24%to 0.0752%,indicating that most of the large particles could be easily removed.Among the four complexing agents,namely,acetic acid,oxalic acid,citric acid,and ethylenediaminetetraacetic acid,oxalic acid exhibited the best demetallization performance.The DFT simulations suggested that the high performance of oxalic acid originated from its 1:1 coordination mode,rigid dicarboxyl structure,and greater binding energy.
