Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with en...Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with enhanced biological activities or improved therapeutic capabilities compared to their natural counterparts. Recent years, transition-metal-promoted functionalization of ubiquitous C-H bonds has been emerged as a powerful and tunable tool in this area, both for backbone diversifications and labeling of specific moieties. These reactions were flexible and expedient in both academic and industrial laboratories, especially considering their atom and step-economy, good functional group compatibility, accurate site selectivity. This review surveys the progress achieved in the late-stage modification of peptides and proteins utilizing transition-metal-catalyzed C-H functionalization with C-C and C-X(F, Cl, O, N, B, etc.) bonds formation.展开更多
The dioxygen affinities and catalytic epoxidation performance of transition-metal hydroxamates were investigated for the first time. The effects of substituents on these properties were also discussed in the paper.
Hydrogen has been identified as one of the most promising sustainable and clean energy. Developing hydrogen evolution reaction(HER) catalyst with high activity is essential for satisfying the future requirements. Cons...Hydrogen has been identified as one of the most promising sustainable and clean energy. Developing hydrogen evolution reaction(HER) catalyst with high activity is essential for satisfying the future requirements. Considering novel advantages of two-dimensional materials and high catalytic activity of atomic transition metal, in this study, using density functional theory calculation, the HER on single transitionmetal(23 different TM atoms) doped phosphorus carbide monolayer(α-PC) has been investigated. The Volmer–Tafel and Volmer–Heyrovsky reaction mechanisms, and the stability of the most promising HER catalyst are also included. The results show that Ir-αPC with high physical and thermal stability has the most optimal value of Gibbs free adsorption energy for H atom. The relationship of d band center and the HER activity shows a volcano-like curve. The calculation of reaction energy barrier indicates that the Volmer-Heyrovsky step is more favorable than the Volmer-Tafel step.展开更多
Hydrogen is a promising sustainable energy to replace fossil fuels owning to its high specific energy and environmental friendliness.Alkaline water electrolysis has been considered as one of the most prospective techn...Hydrogen is a promising sustainable energy to replace fossil fuels owning to its high specific energy and environmental friendliness.Alkaline water electrolysis has been considered as one of the most prospective technologies for large scale hydrogen production.To boost the sluggish kinetics of hydrogen evolution reaction(HER)in alkaline media,abundant materials have been designed and fabricated.Herein,we summarize the key achievements in the development of layered transition-metal hydroxides[TM(OH)x]for efficient alkaline HER.Based on the structure of TM(OH)x,the mechanism of synergistic effect between TM(OH)x and HER active materials is illuminated firstly.Then,recent progress of TM(OH)x-based HER catalysts to optimize the synergistic effect are categorized as TM(OH)x and active materials,including species,structure,morphology and interaction relationship.Furthermore,TM(OH)x-based overall water splitting electrocatalysts and electrodes are summarized in the design principles for high activity and stability.Finally,some of key challenges for further developments and applications of hydrogen production are proposed.展开更多
A comprehensive understanding of the role of the electrocatalyst in photoelectrochemical(PEC)water splitting is central to improving its performance.Herein,taking the Si-based photoanodes(n^(+)p-Si/SiO_(x)/Fe/FeOx/MOO...A comprehensive understanding of the role of the electrocatalyst in photoelectrochemical(PEC)water splitting is central to improving its performance.Herein,taking the Si-based photoanodes(n^(+)p-Si/SiO_(x)/Fe/FeOx/MOOH,M=Fe,Co,Ni)as a model system,we investigate the effect of the transition-metal electrocatalysts on the oxygen evolution reaction(OER).Among the photoanodes with the three different electrocatalysts,the best OER activity,with a low-onset potential of∼1.01 VRHE,a high photocurrent density of 24.10 mA cm^(-2)at 1.23 VRHE,and a remarkable saturation photocurrent density of 38.82 mA cm^(-2),was obtained with the NiOOH overlayer under AM 1.5G simulated sunlight(100 mW cm^(-2))in 1 M KOH electrolyte.The optimal interfacial engineering for electrocatalysts plays a key role for achieving high performance because it promotes interfacial charge transport,provides a larger number of surface active sites,and results in higher OER activity,compared to other electrocatalysts.This study provides insights into how electrocatalysts function in water-splitting devices to guide future studies of solar energy conversion.展开更多
Sustainable production of H2 through electrochemical water splitting is of great importance in the foreseeable future.Transition-metal metaphosphates(TMMPs)have a three-dimensional(3D)open-framework structure and a hi...Sustainable production of H2 through electrochemical water splitting is of great importance in the foreseeable future.Transition-metal metaphosphates(TMMPs)have a three-dimensional(3D)open-framework structure and a high content of P(which exists as PO3-),and therefore have been recognized as highly efficient catalysts for oxygen evolution reaction(OER)and the bottleneck of electrochemical water splitting.Furthermore,TMMPs can also contribute to hydrogen evolution reaction(HER)in alkaline and neutral media by facilitating water dissociation,and thus,overall water splitting can be achieved using this kind of material.In this timely review,we summarize the recent advances in the synthesis of TMMPs and their applications in OER and HER.We present a brief introduction of the structure and synthetic strategies of TMMPs in the first two parts.Then,we review the latest progress made in research on TMMPs as OER,HER,and overall water-splitting electrocatalysts.In this part,the intrinsic activity of TMMPs as well as the current strategy for improving the catalytic activity will be discussed systematically.Finally,we present the future opportunities and the remaining challenges for the application of TMMPs in the electrocatalysis field.展开更多
Field-effect transistors(FETs)present highly sensitive,rapid,and in situ detection capability in chemical and biological analysis.Recently,two-dimensional(2D)transition-metal dichalcogenides(TMDCs)attract significant ...Field-effect transistors(FETs)present highly sensitive,rapid,and in situ detection capability in chemical and biological analysis.Recently,two-dimensional(2D)transition-metal dichalcogenides(TMDCs)attract significant attention as FET channel due to their unique structures and outstanding properties.With the booming of studies on TMDC FETs,we aim to give a timely review on TMDCbased FET sensors for environmental analysis in different media.First,theoretical basics on TMDC and FET sensor are introduced.Then,recent advances of TMDC FET sensor for pollutant detection in gaseous and aqueous media are,respectively,discussed.At last,future perspectives and challenges in practical application and commercialization are given for TMDC FET sensors.This article provides an overview on TMDC sensors for a wide variety of analytes with an emphasize on the increasing demand of advanced sensing technologies in environmental analysis.展开更多
The electronic structure and magnetic properties of the transition-metal （TM） atoms （Sc-Zn, Pt and Au） doped zigzag GaN single-walled nanotubes （NTs） are investigated using first-principles spin-polarized densit...The electronic structure and magnetic properties of the transition-metal （TM） atoms （Sc-Zn, Pt and Au） doped zigzag GaN single-walled nanotubes （NTs） are investigated using first-principles spin-polarized density functional calculations. Our results show that the bindings of all TM atoms are stable with the binding energy in the range of 6-16 eV. The Sc- and V-doped GaN NTs exhibit a nonmagnetic behavior. The GaN NTs doped with Ti, Mn, Ni, Cu and Pt are antiferromagnetic. On the contrary, the Cr-, Fe-, Co-, Zn- and Au-doped GaN NTs show the ferromagnetic characteristics. The Mn- and Co- doped GaN NTs induce the largest local moment of 4#B among these TM atoms. The local magnetic moment is dominated by the contribution from the substitutional TM atom and the N atoms bonded with it.展开更多
Developing highly efficient,durable,and non-noble electrocatalysts for the sluggish anodic oxygen evolution reaction(OER)is the pivotal for meeting the practical demand in water splitting.However,the current transitio...Developing highly efficient,durable,and non-noble electrocatalysts for the sluggish anodic oxygen evolution reaction(OER)is the pivotal for meeting the practical demand in water splitting.However,the current transition-metal electrocatalysts still suffer from low activity and durability on account of poor interfacial reaction kinetics.In this work,a facile solid-state synthesis strategy is developed to construct transition-metal sulfides heterostructures(denoted as MS_(2)/NiS_(2),M=Mo or W)for boosting OER electrocatalysis.As a result,MoS2/NiS2 and WS2/NiS2 show lower overpotentials of 300 mV and 320 mV to achieve the current density of 10 mA·cm^(-2),and smaller Tafel slopes of 60 mV.dec^(-1) and 83 mV.dec^(-1)in 1 mol·L^(-1) KOH,respectively,in comparison with the single MoS2,WS2,NiS2,as well as even the benchmark RuO2.The experiments reveal that the designed heterostructures have strong electronic interactions and spontaneously develop a built-in electric field at the heterointerface with uneven charge distribution based on the difference of band structures,which promote interfacial charge transfer,improve absorptivity of OH-,and modulate the energy level more comparable to the OER.Thus,the designed transition-metal sulfides heterostructures exhibit a remarkably high electrocatalytic activity for OER.This study provides a simple strategy to manipulate the heterostructure interface via an energy level engineering method for OER and can be extended to fabricate other heterostructures for various energy-related applications.展开更多
We report 75As-nuclear magnetic resonance(NMR)and nuclear quadrupole resonance(NQR)measurements on transition-metal arsenides LaRu2As2,KCa2Fe4As4F2,and A2Cr3As3.In the superconducting state of LaRu2As2,a Hebel–Slicht...We report 75As-nuclear magnetic resonance(NMR)and nuclear quadrupole resonance(NQR)measurements on transition-metal arsenides LaRu2As2,KCa2Fe4As4F2,and A2Cr3As3.In the superconducting state of LaRu2As2,a Hebel–Slichter coherence peak is found in the temperature dependence of the spin-lattice relaxation rate 1/T1 just below Tc,which indicates that LaRu2As2 is a full-gap superperconducor.For KCa2Fe4As4F2,antiferromagnetic spin fluctuations are observed in the normal state.We further find that the anisotropy rate RAF=Tc 1/Tab 1 is small and temperature independent,implying that the low energy spin fluctuations are isotropic in spin space.Our results indicate that KCa2Fe4As4F2 is a moderately overdoped iron-arsenide high-temperature superconductor with a stoichiometric composition.For A2Cr3As3(A=Na,K,Rb,Cs),we calculate the electric field gradient by first-principle method and assign the 75As-NQR peaks to two crystallographically different As sites,paving the way for further NMR investigation.展开更多
The oxygenation constants of transition-metal complexes with benzoin Schiff bases were measured and these complexes were first employed as models for mimicking monooxygenase in catalytic epoxidation of styrene. The hi...The oxygenation constants of transition-metal complexes with benzoin Schiff bases were measured and these complexes were first employed as models for mimicking monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 39.6% and 100% respectively at ambient temperature and pressure. The effects of structures of the bridge group R in the ligands on the dioxygen affinities and catalytic activities to epoxidize styrene were also investigated.展开更多
The dioxygen affinities and biomimetic catalytic performance of transition-metal complexes with (15-crown-5) salophen and its substituted derivatives Mere examined. The oxygenation constants of Co(II) complexes with c...The dioxygen affinities and biomimetic catalytic performance of transition-metal complexes with (15-crown-5) salophen and its substituted derivatives Mere examined. The oxygenation constants of Co(II) complexes with crowned bis-Schiff bases were measured and their Mn(III) complexes were employed as models to mimic monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 57.2% and 100% respectively at ambient temperature and pressure. The effects of crown ether ring and substituents R on the dioxygen affinities and catalytic activities were also investigated through comparing with the uncrowned analogues.展开更多
Peroxide ligation of aqueous metal-oxo clusters provides rich speciation and structural diversity.Here,three novel transition-metal derivatives of polyoxometalate anions,[Ni_(2)(H_(2)O)_(10){P_(4)Ta_(6)(O_(2))_(6)O_(2...Peroxide ligation of aqueous metal-oxo clusters provides rich speciation and structural diversity.Here,three novel transition-metal derivatives of polyoxometalate anions,[Ni_(2)(H_(2)O)_(10){P_(4)Ta_(6)(O_(2))_(6)O_(24)}]^(6-)(1a),[Zn(H_(2)O)_(4){P_(4)Ta_(6)(O_(2))_(6)O_(24)}]^(8-)(2a)and[Cd(H_(2)O)_(4){P_(4)Ta_(6)(O_(2))_(6)O_(24)}]^(8-)(3a),have been successfully synthesized by adopting a one-pot reaction strategy.All of these hexatantalates are built from a new-type phosphorus-incorporated hexatantalates.We investigated the solution behaviors,and the peak assignments of the MS spectra indicated some degree of stability of them in water.Furthermore,the proton-conducting ability of compound 1a was also explored and it has shown well conductivity at high relative humidities,with conductivity achieved 1.22×10^(-3) S/cm(85℃,90%RH).展开更多
Transition-metal-catalyzed remote sp^(2)C-H functionalization of aryl sulfonic acids was hardly ever real-ized owing to competitive ortho-C-H functionalization of aryl sulfonates and electron-deficient nature of pheny...Transition-metal-catalyzed remote sp^(2)C-H functionalization of aryl sulfonic acids was hardly ever real-ized owing to competitive ortho-C-H functionalization of aryl sulfonates and electron-deficient nature of phenyl ring.Herein,with the assistance of a practical biaryl indolyl directing template,palladium-catalyzed remote sp^(2)C-H alkylation of aryl sulfonic acids have been achieved in moderate to good yields with exclusive meta selectivity.Moreover,remote meta-selective C-H alkynylation of aryl sulfonic acids was also accomplished with a rhodium catalyst.These meta-C-H functionalized products proved to be the superior synthetic precursors,which are difficult to access using the conventional strategy.展开更多
A highly site-selective intermolecular trifluoromethylimination of activated and unactivated olefins was reported under transition-metal-and photosensitizer-free conditions.This newly developed strategy provides strai...A highly site-selective intermolecular trifluoromethylimination of activated and unactivated olefins was reported under transition-metal-and photosensitizer-free conditions.This newly developed strategy provides straightforward and efficient access to diverse value-added vicinal trifluoromethyl amines without resorting to the pre-functionalized reagents.Mechanistic experiments demonstrate that the approach proceeded through CF_(3)and iminyl two-radicals process,which were generated directly from commercially available benzophenone imine in a novel electron-donor mode via a SET process activated by the bifunctional hypervalent iodine reagents.The synthetic potential of the protocols was further showcased via the condensation/amination sequential cascade,and transformations to accessβ-CF_(3)primary amines.展开更多
Nitrene transfer reactions are powerful tools in synthetic organic chemistry.In recent years,transitionmetal catalyzed nitrene transfer reactions with carbamates as the nitrene precursors have been widely pursued.Such...Nitrene transfer reactions are powerful tools in synthetic organic chemistry.In recent years,transitionmetal catalyzed nitrene transfer reactions with carbamates as the nitrene precursors have been widely pursued.Such species undergoes facile C-H amination,aziridination,and bifunctionalization of alkenes under the catalysis of different transition metals including Rh,Fe,Ru and others,enabling the efficient construction of various nitrogen-containing molecules.In this review,the recent developments in nitrene transfer reactions with carbamates via N-O bond cleavage were introduced based on different types of reaction,and the key mechanistic information and synthetic applications of the methodologies were discussed.展开更多
2D MBenes have been theoretically predicted to possess unique electronic structures and physicochemical properties,and thus shown great promise in various applications.However,the synthesis of individual single-layer ...2D MBenes have been theoretically predicted to possess unique electronic structures and physicochemical properties,and thus shown great promise in various applications.However,the synthesis of individual single-layer MBene remains a grand challenge due to its orthorhombic structure of MAB phases.Recently,scientists from Link?ping University have fabricated 2D monolayer Mo4/3B2-xTzwith ordered metal vacancies.Their results demonstrated the feasibility of top-down approach by chemical exfoliation of laminated compounds and provided the principle for further preparation of a wealth of MBenes.展开更多
Raman vibrational spectra of the selected basic （hydroxyl OH and deuteroxyl OD） transition-metal halides, geomet- rically frustrated material series α-, β-, γ-Cu2（OH）3Cl, α-Cu2（OH）3Br, β-Ni2（OH）3Cl, β-Co...Raman vibrational spectra of the selected basic （hydroxyl OH and deuteroxyl OD） transition-metal halides, geomet- rically frustrated material series α-, β-, γ-Cu2（OH）3Cl, α-Cu2（OH）3Br, β-Ni2（OH）3Cl, β-Co2（OH）3Cl, β-Co2（OH）3Br, γ-Cu2（OD）3Cl, and β-Co2（OD）3Cl are measured at room temperature and analysed to investigate the relationship be- tween the microstructured OH environments and their respective Raman spectra. Among these selected samples, the last two are used to determine the OH stretching vibration region （3600 cm-1-3300 cm-1） and OH bending vibra- tion region （1000 cm-1-600 cm-1） of OH systems in the spectra. Through the comparative analysis of the distances d（metal-O）, d（O-halogen）, and d（OH）, the strong metal-O interaction and trimeric hydrogen bond （Car, C8 or C1 symmetry） are found in every material, but both determine simultaneously an ultimate d（OH）, and therefore an OH stretching vibration frequency. According to the approximately linear relationship between the OH stretching vibration frequency and d（OH）, some unavailable d（OH） are guessed and some doubtful d（OH） are suggested to be corrected. In addition, it is demonstrated in brief that the OH bending vibration frequency is also of importance to check the more detailed crystal microstructure relating to the OH group.展开更多
The oxygenation constants and thermodynamic parameter (ΔHo, ΔSo) of Co (II) complexes with unsymmetrical bis-Schiff baeses were measured and their Mn(III) complexes as models of mimicking monooxygenase were employed...The oxygenation constants and thermodynamic parameter (ΔHo, ΔSo) of Co (II) complexes with unsymmetrical bis-Schiff baeses were measured and their Mn(III) complexes as models of mimicking monooxygenase were employed to catalyze epoxidation of styrene. The effect of substituent R in a salicylidene of ML1~ML4 [ M = Co (II), Mn (III)Cl ] on the dioxygen affinities and biomimetic catalytic oxidation performance were also investigated. Among them, the MnL4Cl containing a pendant benzoaza crown ether ring showed highest conversion and selectiviy up to 54.9% and 96.9% respectively.展开更多
Transition-metal chalcogenide nanowires(TMCN) as a viable candidate for nanoscale applications have been attracting much attention for the last few decades. Starting from the rigid building block of M6 octahedra(M = t...Transition-metal chalcogenide nanowires(TMCN) as a viable candidate for nanoscale applications have been attracting much attention for the last few decades. Starting from the rigid building block of M6 octahedra(M = transition metal),depending on the way of connection between M6 and decoration by chalcogenide atoms, multiple types of extended TMCN nanowires can be constructed based on some basic rules of backbone construction proposed here. Note that the well-known Chevrel-phase based M6X6 and M6X9(X = chalcogenide atom) nanowires, which are among our proposed structures, have been successfully synthesized by experiment and well studied. More interestingly, based on the construction principles, we predict three new structural phases(the cap, edge, and C&E phases) of Mo5S4, one of which(the edge phase) has been obtained by top-down electron beam lithography on two-dimensional MoS2, and the C&E phase is yet to be synthesized but appears more stable than the edge phase. The stability of the new phases of Mo5S4 is further substantiated by crystal orbital overlapping population(COOP), phonon dispersion relation, and thermodynamic calculation. The barrier of the structural transition between different phases of Mo5S4 shows that it is very likely to realize an conversion from the experimentally achieved structure to the most stable C&E phase. The calculated electronic structure shows an interesting band nesting between valence and conduction bands of the C&E Mo5S4 phase, suggesting that such a nanowire structure can be well suitable for optoelectronic sensor applications.展开更多
基金the support from the National Key R&D Program of China(No. 2017YFA0505400)the National Natural Science Foundation of China (Nos. 21572214, 21702200)
文摘Late-stage modification of peptides and proteins meets the increasing demand in biochemical and pharmaceutical communities. These modification strategies could provide functionalized nonproteinogenic analogues with enhanced biological activities or improved therapeutic capabilities compared to their natural counterparts. Recent years, transition-metal-promoted functionalization of ubiquitous C-H bonds has been emerged as a powerful and tunable tool in this area, both for backbone diversifications and labeling of specific moieties. These reactions were flexible and expedient in both academic and industrial laboratories, especially considering their atom and step-economy, good functional group compatibility, accurate site selectivity. This review surveys the progress achieved in the late-stage modification of peptides and proteins utilizing transition-metal-catalyzed C-H functionalization with C-C and C-X(F, Cl, O, N, B, etc.) bonds formation.
文摘The dioxygen affinities and catalytic epoxidation performance of transition-metal hydroxamates were investigated for the first time. The effects of substituents on these properties were also discussed in the paper.
基金Erwin Edward Hart Professorship, Natural Sciences and Engineering Research Council of Canada (NSERC, RGPIN-2018-04642)University of Toronto for financial supports, and China Scholarship Council under Grant No. 201906270124。
文摘Hydrogen has been identified as one of the most promising sustainable and clean energy. Developing hydrogen evolution reaction(HER) catalyst with high activity is essential for satisfying the future requirements. Considering novel advantages of two-dimensional materials and high catalytic activity of atomic transition metal, in this study, using density functional theory calculation, the HER on single transitionmetal(23 different TM atoms) doped phosphorus carbide monolayer(α-PC) has been investigated. The Volmer–Tafel and Volmer–Heyrovsky reaction mechanisms, and the stability of the most promising HER catalyst are also included. The results show that Ir-αPC with high physical and thermal stability has the most optimal value of Gibbs free adsorption energy for H atom. The relationship of d band center and the HER activity shows a volcano-like curve. The calculation of reaction energy barrier indicates that the Volmer-Heyrovsky step is more favorable than the Volmer-Tafel step.
基金supported by the National Key Research and Development Program(2017YFC0306403)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA09030104,XDA22010601)the Youth Innovation Promotion Association of the Chinese Academy of Sciences~~
文摘Hydrogen is a promising sustainable energy to replace fossil fuels owning to its high specific energy and environmental friendliness.Alkaline water electrolysis has been considered as one of the most prospective technologies for large scale hydrogen production.To boost the sluggish kinetics of hydrogen evolution reaction(HER)in alkaline media,abundant materials have been designed and fabricated.Herein,we summarize the key achievements in the development of layered transition-metal hydroxides[TM(OH)x]for efficient alkaline HER.Based on the structure of TM(OH)x,the mechanism of synergistic effect between TM(OH)x and HER active materials is illuminated firstly.Then,recent progress of TM(OH)x-based HER catalysts to optimize the synergistic effect are categorized as TM(OH)x and active materials,including species,structure,morphology and interaction relationship.Furthermore,TM(OH)x-based overall water splitting electrocatalysts and electrodes are summarized in the design principles for high activity and stability.Finally,some of key challenges for further developments and applications of hydrogen production are proposed.
文摘A comprehensive understanding of the role of the electrocatalyst in photoelectrochemical(PEC)water splitting is central to improving its performance.Herein,taking the Si-based photoanodes(n^(+)p-Si/SiO_(x)/Fe/FeOx/MOOH,M=Fe,Co,Ni)as a model system,we investigate the effect of the transition-metal electrocatalysts on the oxygen evolution reaction(OER).Among the photoanodes with the three different electrocatalysts,the best OER activity,with a low-onset potential of∼1.01 VRHE,a high photocurrent density of 24.10 mA cm^(-2)at 1.23 VRHE,and a remarkable saturation photocurrent density of 38.82 mA cm^(-2),was obtained with the NiOOH overlayer under AM 1.5G simulated sunlight(100 mW cm^(-2))in 1 M KOH electrolyte.The optimal interfacial engineering for electrocatalysts plays a key role for achieving high performance because it promotes interfacial charge transport,provides a larger number of surface active sites,and results in higher OER activity,compared to other electrocatalysts.This study provides insights into how electrocatalysts function in water-splitting devices to guide future studies of solar energy conversion.
基金the Natural Science Foundation of China(Grant Nos.21871065,22209129,and 22071038)the Heilongjiang Touyan Team(HITTY-20190033)+3 种基金High-Level Innovation and Entrepreneurship(QCYRCXM-2022-123)the Talent Project of Qinchuangyuan and Interdisciplinary Research Foundation of HIT(IR2021205)Professor Li acknowledges the financial support from the“Young Talent Support Plan”of Xi'an Jiaotong University(HG6J024)the“Young Talent Lift Plan”of Xi'an city(095920221352).
文摘Sustainable production of H2 through electrochemical water splitting is of great importance in the foreseeable future.Transition-metal metaphosphates(TMMPs)have a three-dimensional(3D)open-framework structure and a high content of P(which exists as PO3-),and therefore have been recognized as highly efficient catalysts for oxygen evolution reaction(OER)and the bottleneck of electrochemical water splitting.Furthermore,TMMPs can also contribute to hydrogen evolution reaction(HER)in alkaline and neutral media by facilitating water dissociation,and thus,overall water splitting can be achieved using this kind of material.In this timely review,we summarize the recent advances in the synthesis of TMMPs and their applications in OER and HER.We present a brief introduction of the structure and synthetic strategies of TMMPs in the first two parts.Then,we review the latest progress made in research on TMMPs as OER,HER,and overall water-splitting electrocatalysts.In this part,the intrinsic activity of TMMPs as well as the current strategy for improving the catalytic activity will be discussed systematically.Finally,we present the future opportunities and the remaining challenges for the application of TMMPs in the electrocatalysis field.
基金the National Natural Science Foundation of China(No.21707102)the Fundamental Research Funds for the Central Universities,China(No.22120180524).
文摘Field-effect transistors(FETs)present highly sensitive,rapid,and in situ detection capability in chemical and biological analysis.Recently,two-dimensional(2D)transition-metal dichalcogenides(TMDCs)attract significant attention as FET channel due to their unique structures and outstanding properties.With the booming of studies on TMDC FETs,we aim to give a timely review on TMDCbased FET sensors for environmental analysis in different media.First,theoretical basics on TMDC and FET sensor are introduced.Then,recent advances of TMDC FET sensor for pollutant detection in gaseous and aqueous media are,respectively,discussed.At last,future perspectives and challenges in practical application and commercialization are given for TMDC FET sensors.This article provides an overview on TMDC sensors for a wide variety of analytes with an emphasize on the increasing demand of advanced sensing technologies in environmental analysis.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB619304)the National Natural Science Foundation of China(Grant Nos.51072007,91021017,11364030,and 11047018)the Beijing Natural Science Foundation,China(Grant No.1112007)
文摘The electronic structure and magnetic properties of the transition-metal （TM） atoms （Sc-Zn, Pt and Au） doped zigzag GaN single-walled nanotubes （NTs） are investigated using first-principles spin-polarized density functional calculations. Our results show that the bindings of all TM atoms are stable with the binding energy in the range of 6-16 eV. The Sc- and V-doped GaN NTs exhibit a nonmagnetic behavior. The GaN NTs doped with Ti, Mn, Ni, Cu and Pt are antiferromagnetic. On the contrary, the Cr-, Fe-, Co-, Zn- and Au-doped GaN NTs show the ferromagnetic characteristics. The Mn- and Co- doped GaN NTs induce the largest local moment of 4#B among these TM atoms. The local magnetic moment is dominated by the contribution from the substitutional TM atom and the N atoms bonded with it.
基金supported by the National Natural Science Foun-dation of China(21922814,22138012,21961160745,21921005,22178349,22078333,22108281 and 31961133019)Excellent Member in Youth Innovation Promotion Association,Chinese Academy of Sciences(Y202014)Shandong Energy Institute(Grant Number SEI 1202133).
文摘Developing highly efficient,durable,and non-noble electrocatalysts for the sluggish anodic oxygen evolution reaction(OER)is the pivotal for meeting the practical demand in water splitting.However,the current transition-metal electrocatalysts still suffer from low activity and durability on account of poor interfacial reaction kinetics.In this work,a facile solid-state synthesis strategy is developed to construct transition-metal sulfides heterostructures(denoted as MS_(2)/NiS_(2),M=Mo or W)for boosting OER electrocatalysis.As a result,MoS2/NiS2 and WS2/NiS2 show lower overpotentials of 300 mV and 320 mV to achieve the current density of 10 mA·cm^(-2),and smaller Tafel slopes of 60 mV.dec^(-1) and 83 mV.dec^(-1)in 1 mol·L^(-1) KOH,respectively,in comparison with the single MoS2,WS2,NiS2,as well as even the benchmark RuO2.The experiments reveal that the designed heterostructures have strong electronic interactions and spontaneously develop a built-in electric field at the heterointerface with uneven charge distribution based on the difference of band structures,which promote interfacial charge transfer,improve absorptivity of OH-,and modulate the energy level more comparable to the OER.Thus,the designed transition-metal sulfides heterostructures exhibit a remarkably high electrocatalytic activity for OER.This study provides a simple strategy to manipulate the heterostructure interface via an energy level engineering method for OER and can be extended to fabricate other heterostructures for various energy-related applications.
基金National Natural Science Foundation of China(Grant Nos.11674377,11634015,and 11974405)the National Key R&D Program of China(Grant Nos.2017YFA0302904 and 2016YFA0300502)J.Y.also acknowledges support by the Youth Innovation Promotion Association of Chinese Academy of Sciences.
文摘We report 75As-nuclear magnetic resonance(NMR)and nuclear quadrupole resonance(NQR)measurements on transition-metal arsenides LaRu2As2,KCa2Fe4As4F2,and A2Cr3As3.In the superconducting state of LaRu2As2,a Hebel–Slichter coherence peak is found in the temperature dependence of the spin-lattice relaxation rate 1/T1 just below Tc,which indicates that LaRu2As2 is a full-gap superperconducor.For KCa2Fe4As4F2,antiferromagnetic spin fluctuations are observed in the normal state.We further find that the anisotropy rate RAF=Tc 1/Tab 1 is small and temperature independent,implying that the low energy spin fluctuations are isotropic in spin space.Our results indicate that KCa2Fe4As4F2 is a moderately overdoped iron-arsenide high-temperature superconductor with a stoichiometric composition.For A2Cr3As3(A=Na,K,Rb,Cs),we calculate the electric field gradient by first-principle method and assign the 75As-NQR peaks to two crystallographically different As sites,paving the way for further NMR investigation.
文摘The oxygenation constants of transition-metal complexes with benzoin Schiff bases were measured and these complexes were first employed as models for mimicking monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 39.6% and 100% respectively at ambient temperature and pressure. The effects of structures of the bridge group R in the ligands on the dioxygen affinities and catalytic activities to epoxidize styrene were also investigated.
基金the National Natural Science Foundation of China.
文摘The dioxygen affinities and biomimetic catalytic performance of transition-metal complexes with (15-crown-5) salophen and its substituted derivatives Mere examined. The oxygenation constants of Co(II) complexes with crowned bis-Schiff bases were measured and their Mn(III) complexes were employed as models to mimic monooxygenase in catalytic epoxidation of styrene. The highest conversion and selectivity were up to 57.2% and 100% respectively at ambient temperature and pressure. The effects of crown ether ring and substituents R on the dioxygen affinities and catalytic activities were also investigated through comparing with the uncrowned analogues.
基金funded by the National Natural Science Foundation of China(Nos.22171071,22071044,21771054 and 21571050)。
文摘Peroxide ligation of aqueous metal-oxo clusters provides rich speciation and structural diversity.Here,three novel transition-metal derivatives of polyoxometalate anions,[Ni_(2)(H_(2)O)_(10){P_(4)Ta_(6)(O_(2))_(6)O_(24)}]^(6-)(1a),[Zn(H_(2)O)_(4){P_(4)Ta_(6)(O_(2))_(6)O_(24)}]^(8-)(2a)and[Cd(H_(2)O)_(4){P_(4)Ta_(6)(O_(2))_(6)O_(24)}]^(8-)(3a),have been successfully synthesized by adopting a one-pot reaction strategy.All of these hexatantalates are built from a new-type phosphorus-incorporated hexatantalates.We investigated the solution behaviors,and the peak assignments of the MS spectra indicated some degree of stability of them in water.Furthermore,the proton-conducting ability of compound 1a was also explored and it has shown well conductivity at high relative humidities,with conductivity achieved 1.22×10^(-3) S/cm(85℃,90%RH).
基金Financial support from the National Natural Science Foundation of China(No.22171145 to Z.Jin,32072440 to X.Xu)is gratefully acknowledged.
文摘Transition-metal-catalyzed remote sp^(2)C-H functionalization of aryl sulfonic acids was hardly ever real-ized owing to competitive ortho-C-H functionalization of aryl sulfonates and electron-deficient nature of phenyl ring.Herein,with the assistance of a practical biaryl indolyl directing template,palladium-catalyzed remote sp^(2)C-H alkylation of aryl sulfonic acids have been achieved in moderate to good yields with exclusive meta selectivity.Moreover,remote meta-selective C-H alkynylation of aryl sulfonic acids was also accomplished with a rhodium catalyst.These meta-C-H functionalized products proved to be the superior synthetic precursors,which are difficult to access using the conventional strategy.
基金Financial support from the National Natural Science Foundation of China(Nos.22201239,22205192 and 22271244)the Hunan Provincial Natural Science Foundation of China(No.2022JJ40429)+2 种基金the Scientific Research Fund of Hunan Provincial Education Department(No.21B0130)the Open Research Fund of School of Chemistry and Chemical Engineering,Henan Normal University(No.2022C02)the Process Intensification&Green Chemical Engineering Innovation Team Project of Hunan Province。
文摘A highly site-selective intermolecular trifluoromethylimination of activated and unactivated olefins was reported under transition-metal-and photosensitizer-free conditions.This newly developed strategy provides straightforward and efficient access to diverse value-added vicinal trifluoromethyl amines without resorting to the pre-functionalized reagents.Mechanistic experiments demonstrate that the approach proceeded through CF_(3)and iminyl two-radicals process,which were generated directly from commercially available benzophenone imine in a novel electron-donor mode via a SET process activated by the bifunctional hypervalent iodine reagents.The synthetic potential of the protocols was further showcased via the condensation/amination sequential cascade,and transformations to accessβ-CF_(3)primary amines.
基金the financial support provided by the National Natural Science Foundation of China(Nos.21572163 and 21873074)the Wenzhou Science&Technology Bureau(No.G20210032)。
文摘Nitrene transfer reactions are powerful tools in synthetic organic chemistry.In recent years,transitionmetal catalyzed nitrene transfer reactions with carbamates as the nitrene precursors have been widely pursued.Such species undergoes facile C-H amination,aziridination,and bifunctionalization of alkenes under the catalysis of different transition metals including Rh,Fe,Ru and others,enabling the efficient construction of various nitrogen-containing molecules.In this review,the recent developments in nitrene transfer reactions with carbamates via N-O bond cleavage were introduced based on different types of reaction,and the key mechanistic information and synthetic applications of the methodologies were discussed.
基金supported by the National Natural Science Foundation of China(Nos.52172205,11804166)the China Postdoctoral Science Foundation(No.2018M630587)Tianjin Natural Science Foundation(No.18JCQNJC77100)。
文摘2D MBenes have been theoretically predicted to possess unique electronic structures and physicochemical properties,and thus shown great promise in various applications.However,the synthesis of individual single-layer MBene remains a grand challenge due to its orthorhombic structure of MAB phases.Recently,scientists from Link?ping University have fabricated 2D monolayer Mo4/3B2-xTzwith ordered metal vacancies.Their results demonstrated the feasibility of top-down approach by chemical exfoliation of laminated compounds and provided the principle for further preparation of a wealth of MBenes.
基金Project supported by the Grant-in-Aid for Scientific Research on Priority Area from the Ministry of Education,Culture,Sports,Science and Technology,Japan (Grant No. Tokutei 22014008)
文摘Raman vibrational spectra of the selected basic （hydroxyl OH and deuteroxyl OD） transition-metal halides, geomet- rically frustrated material series α-, β-, γ-Cu2（OH）3Cl, α-Cu2（OH）3Br, β-Ni2（OH）3Cl, β-Co2（OH）3Cl, β-Co2（OH）3Br, γ-Cu2（OD）3Cl, and β-Co2（OD）3Cl are measured at room temperature and analysed to investigate the relationship be- tween the microstructured OH environments and their respective Raman spectra. Among these selected samples, the last two are used to determine the OH stretching vibration region （3600 cm-1-3300 cm-1） and OH bending vibra- tion region （1000 cm-1-600 cm-1） of OH systems in the spectra. Through the comparative analysis of the distances d（metal-O）, d（O-halogen）, and d（OH）, the strong metal-O interaction and trimeric hydrogen bond （Car, C8 or C1 symmetry） are found in every material, but both determine simultaneously an ultimate d（OH）, and therefore an OH stretching vibration frequency. According to the approximately linear relationship between the OH stretching vibration frequency and d（OH）, some unavailable d（OH） are guessed and some doubtful d（OH） are suggested to be corrected. In addition, it is demonstrated in brief that the OH bending vibration frequency is also of importance to check the more detailed crystal microstructure relating to the OH group.
文摘The oxygenation constants and thermodynamic parameter (ΔHo, ΔSo) of Co (II) complexes with unsymmetrical bis-Schiff baeses were measured and their Mn(III) complexes as models of mimicking monooxygenase were employed to catalyze epoxidation of styrene. The effect of substituent R in a salicylidene of ML1~ML4 [ M = Co (II), Mn (III)Cl ] on the dioxygen affinities and biomimetic catalytic oxidation performance were also investigated. Among them, the MnL4Cl containing a pendant benzoaza crown ether ring showed highest conversion and selectiviy up to 54.9% and 96.9% respectively.
基金Project supported by the National Natural Science Foundation of China(Grant No.51702146)the College Students’ Innovation and Entrepreneurship Projects,China(Grant No.201710148000072)Liaoning Province Doctor Startup Fund,China(Grant No.201601325)
文摘Transition-metal chalcogenide nanowires(TMCN) as a viable candidate for nanoscale applications have been attracting much attention for the last few decades. Starting from the rigid building block of M6 octahedra(M = transition metal),depending on the way of connection between M6 and decoration by chalcogenide atoms, multiple types of extended TMCN nanowires can be constructed based on some basic rules of backbone construction proposed here. Note that the well-known Chevrel-phase based M6X6 and M6X9(X = chalcogenide atom) nanowires, which are among our proposed structures, have been successfully synthesized by experiment and well studied. More interestingly, based on the construction principles, we predict three new structural phases(the cap, edge, and C&E phases) of Mo5S4, one of which(the edge phase) has been obtained by top-down electron beam lithography on two-dimensional MoS2, and the C&E phase is yet to be synthesized but appears more stable than the edge phase. The stability of the new phases of Mo5S4 is further substantiated by crystal orbital overlapping population(COOP), phonon dispersion relation, and thermodynamic calculation. The barrier of the structural transition between different phases of Mo5S4 shows that it is very likely to realize an conversion from the experimentally achieved structure to the most stable C&E phase. The calculated electronic structure shows an interesting band nesting between valence and conduction bands of the C&E Mo5S4 phase, suggesting that such a nanowire structure can be well suitable for optoelectronic sensor applications.
