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
We investigated the role of metal atomization and solvent decomposition into reductive species and carbon clusters in the phase formation of transition-metal carbides(TMCs;namely,Co_(3)C,Fe_(3)C,TiC,and MoC)by pulsed ...We investigated the role of metal atomization and solvent decomposition into reductive species and carbon clusters in the phase formation of transition-metal carbides(TMCs;namely,Co_(3)C,Fe_(3)C,TiC,and MoC)by pulsed laser ablation of Co,Fe,Ti,and Mo metals in acetone.The interaction between carbon s-p-orbitals and metal d-orbitals causes a redistribution of valence structure through charge transfer,leading to the formation of surface defects as observed by X-ray photoelectron spectroscopy.These defects influence the evolved TMCs,making them effective for hydrogen and oxygen evolution reactions(HER and OER)in an alkaline medium.Co_(3)C with more oxygen affinity promoted CoO(OH)intermediates,and the electrochemical surface oxidation to Co_(3)O_(4)was captured via in situ/operando electrochemical Raman probes,increasing the number of active sites for OER activity.MoC with more d-vacancies exhibits strong hydrogen binding,promoting HER kinetics,whereas Fe_(3)C and TiC with more defect states to trap charge carriers may hinder both OER and HER activities.The results show that the assembled membrane-less electrolyzer with Co_(3)C∥Co_(3)C and MoC∥MoC electrodes requires~2.01 and 1.99 V,respectively,to deliver a 10 mA cm−2 with excellent electrochemical and structural stability.In addition,the ascertained pulsed laser synthesis mechanism and unit-cell packing relations will open up sustainable pathways for obtaining highly stable electrocatalysts for electrolyzers.展开更多
Chiral carbonyl compounds frequently occur in natural products and pharmaceuticals. Additionally, they serve as important intermediates in organic synthesis. Transition metal-catalyzed asymmetric carbonylative cross-c...Chiral carbonyl compounds frequently occur in natural products and pharmaceuticals. Additionally, they serve as important intermediates in organic synthesis. Transition metal-catalyzed asymmetric carbonylative cross-coupling reactions are among the most straightforward and effective methods for synthesizing chiral carbonyl compounds, including esters, amides, and ketones. The advances in asymmetric carbonylative cross-coupling reactions using various O-, N-, C-, and S-containing nucleophiles or electrophiles over the past decade are summarized.展开更多
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 hybridization between oxygen 2p and transition-metal 3d states largely determines the electronic structure near the Fermi level and related functionalities of transition-metal oxides(TMOs).Considerable efforts hav...The hybridization between oxygen 2p and transition-metal 3d states largely determines the electronic structure near the Fermi level and related functionalities of transition-metal oxides(TMOs).Considerable efforts have been made to manipulate the p-d hybridization in TMOs by tailoring the spatial orbital overlap via structural engineering.Here,we demonstrate enhanced p-d hybridization in Ba^(2+)-doped LaNiO_(3)epitaxial films by simultaneously modifying both the spatial and energetic overlaps between the O-2p and Ni-3d orbitals.Combining x-ray absorption spectroscopy and firstprinciples calculations,we reveal that the enhanced hybridization stems from the synergistic effects of a reduced chargetransfer energy due to hole injection and an increased spatial orbital overlap due to straightening of Ni-O-Ni bonds.We further show that the enhanced p-d hybridization can be utilized to promote the oxygen evolution activity of LaNiO_(3).This work sheds new insights into the fine-tuning of the electronic structures of TMOs for enhanced functionalities.展开更多
The family of transition-metal dipnictides,MX2(M:metal,X:N,P,As,Sb,and Bi),has emerged as an important quantum material system due to its unique physical properties,such as large magnetoresistance,colossal Seebeck coe...The family of transition-metal dipnictides,MX2(M:metal,X:N,P,As,Sb,and Bi),has emerged as an important quantum material system due to its unique physical properties,such as large magnetoresistance,colossal Seebeck coefficients,and Weyl semimetal characteristics.In order to study the M-site ions effect on the lattice structure and the related dynamics,we compared two isostructural compounds,FeSb_(2)and RuSb_(2).Neutron diffraction,specific heat,and Raman scattering spectra of RuSb_(2)were measured.We found that the thermal expansion coefficients are isotropic for RuSb_(2),in contrast to the anisotropic behavior reported previously in FeSb_(2).Moreover,the specific heat of RuSb_(2)shows a bosonlike anomaly around 25 K.Four of the six predicted vibrational modes were identified by polarized Raman scattering spectra and successfully simulated by ab initio calculations.Meanwhile,the temperature-dependent linewidths reveal that phonon-phonon interactions might dominate above 50 K,while electron-phonon coupling remains relatively weak.展开更多
The prevalence of wide-bandgap semiconductors urges the development of advanced soft magnetic materials for high-frequency applications.While soft magnetic alloys are limited by resonances at elevated frequencies,the ...The prevalence of wide-bandgap semiconductors urges the development of advanced soft magnetic materials for high-frequency applications.While soft magnetic alloys are limited by resonances at elevated frequencies,the incorporation of planar anisotropy serves as an effective strategy to overcome this dilemma and extend their potential for high-frequency applications.Herein,nanocrystalline Y_(2)Co_(14)B alloys have been designed with tuned magnetocrystalline and shape bi-anisotropy via melt spinning and magnetic field-assisted annealing.With the application of zero,transverse,rotational and longitudinal magnetic fields(denoted as ZFA,TFA,RFA and LFA),the effects of field direction and annealing time on microstructural and performance evolution have been investigated.Compared with ZFA,magnetic field-assisted annealing not only promotes the growth of nanograins but also alters the coincidence degree between intrinsic easy-plane(IEP)and artificial easy-plane(AEP)structures.While the random distribution of IEP structure is achieved for the RFA due to the formation of non-orientated nanograins,directional magnetic field-assisted annealing contributes to preferentially orientated(006)nanograins,especially for the LFA,resulting in optimal coincidence between the magnetocrystalline anisotropy and shape anisotropy.Such enhancement facilitates the transformation of magnetic domain structures into in-plane configurations with strip-like features.Consequently,a large ratio between the out-of-plane and in-plane anisotropy(H_(out)/H_(in))and improved softness of the alloy can be achieved,providing valuable references for future fabrication of rare-earth(R)transition-metal(T)alloys with superior easy-plane characteristics.展开更多
Two-dimensional(2D)transition-metal dichalcogenide(TMD)monolayers based on become a promising platform to study photonics and optoelectronics.Electrically controlling the excitonic properties of TMD monolayers can be ...Two-dimensional(2D)transition-metal dichalcogenide(TMD)monolayers based on become a promising platform to study photonics and optoelectronics.Electrically controlling the excitonic properties of TMD monolayers can be realized in different devices.In this work,we realize the strong coupling between the excitons of WS_(2)monolayers and a photonic cavity mode in a liquid crystal microcavity.The formed exciton polaritons can be electrically tuned by applying voltage to the microcavity.Our work offers a way to study exciton-polariton manipulation based on TMD monolayers by electrical methods at room temperature.展开更多
P2-type layered transition-metal oxides with high energy density and rich variety have attracted extensive attention for sodium-ion batteries(SIBs)in grid-scale energy storage application,but they usually suffer from ...P2-type layered transition-metal oxides with high energy density and rich variety have attracted extensive attention for sodium-ion batteries(SIBs)in grid-scale energy storage application,but they usually suffer from sluggish kinetics and large volume change upon cycling.Herein,we designed a highperformance P2-type Na_(0.67)Ni_(0.31)Mn_(0.67)Mo_(0.02)O_(2)(NNMMO)cathode with regulated electronic environment and Na^(+)zigzag ordering modulation via high-valence Mo6+stabilization engineering.The achieved NNMMO cathode exhibits a high-rate capability with a reversible capacity of 77.2 m Ah/g at 10 C and a long cycle life with a capacity retention of 75%at 2 C after 1000 cycles.In addition,in situ X-ray diffraction and ex-situ X-ray absorption fine structure spectroscopy characterizations verify that the presence of Mo^(6+)also stabilizes the desodiated structure through a pinning effect,achieving an extremely low volume change of 1.04%upon Na^(+)extraction.The quantified diffusional analysis and theoretical calculations demonstrate that the Mo^(6+)-doping improves the Na+diffusion kinetics,optimizes the energy band structure and enhances the TM-O bond strength.Additionally,the as-fabricated pouch cells by paring NNMMO cathode and hard carbon anode show impressive cycling stability with an energy density of 296.7 Wh/kg.This study broadens the perspective for high-valence metal ion doping to obtain superior cathode materials and pave the way for developing high-energy-density SIBs.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
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National Research Foundation of Korea,Grant/Award Numbers:2019H1D3A1A01071209,2021R1I1A1A01060380,2022R1A2C2010686,2022R1A4A3033528Korea Basic Science Institute,Grant/Award Numbers:2019R1A6C1010042,2021R1A6C103A427。
文摘We investigated the role of metal atomization and solvent decomposition into reductive species and carbon clusters in the phase formation of transition-metal carbides(TMCs;namely,Co_(3)C,Fe_(3)C,TiC,and MoC)by pulsed laser ablation of Co,Fe,Ti,and Mo metals in acetone.The interaction between carbon s-p-orbitals and metal d-orbitals causes a redistribution of valence structure through charge transfer,leading to the formation of surface defects as observed by X-ray photoelectron spectroscopy.These defects influence the evolved TMCs,making them effective for hydrogen and oxygen evolution reactions(HER and OER)in an alkaline medium.Co_(3)C with more oxygen affinity promoted CoO(OH)intermediates,and the electrochemical surface oxidation to Co_(3)O_(4)was captured via in situ/operando electrochemical Raman probes,increasing the number of active sites for OER activity.MoC with more d-vacancies exhibits strong hydrogen binding,promoting HER kinetics,whereas Fe_(3)C and TiC with more defect states to trap charge carriers may hinder both OER and HER activities.The results show that the assembled membrane-less electrolyzer with Co_(3)C∥Co_(3)C and MoC∥MoC electrodes requires~2.01 and 1.99 V,respectively,to deliver a 10 mA cm−2 with excellent electrochemical and structural stability.In addition,the ascertained pulsed laser synthesis mechanism and unit-cell packing relations will open up sustainable pathways for obtaining highly stable electrocatalysts for electrolyzers.
文摘Chiral carbonyl compounds frequently occur in natural products and pharmaceuticals. Additionally, they serve as important intermediates in organic synthesis. Transition metal-catalyzed asymmetric carbonylative cross-coupling reactions are among the most straightforward and effective methods for synthesizing chiral carbonyl compounds, including esters, amides, and ketones. The advances in asymmetric carbonylative cross-coupling reactions using various O-, N-, C-, and S-containing nucleophiles or electrophiles over the past decade are summarized.
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.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1402902)the National Natural Science Foundation of China(Grant Nos.12374179,12074119,12374145,051B22001,12104157,12134003,and 12304218)the Shanghai Pujiang Program(Grant No.23PJ1402200).
文摘The hybridization between oxygen 2p and transition-metal 3d states largely determines the electronic structure near the Fermi level and related functionalities of transition-metal oxides(TMOs).Considerable efforts have been made to manipulate the p-d hybridization in TMOs by tailoring the spatial orbital overlap via structural engineering.Here,we demonstrate enhanced p-d hybridization in Ba^(2+)-doped LaNiO_(3)epitaxial films by simultaneously modifying both the spatial and energetic overlaps between the O-2p and Ni-3d orbitals.Combining x-ray absorption spectroscopy and firstprinciples calculations,we reveal that the enhanced hybridization stems from the synergistic effects of a reduced chargetransfer energy due to hole injection and an increased spatial orbital overlap due to straightening of Ni-O-Ni bonds.We further show that the enhanced p-d hybridization can be utilized to promote the oxygen evolution activity of LaNiO_(3).This work sheds new insights into the fine-tuning of the electronic structures of TMOs for enhanced functionalities.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U2032213 and 12334008)the Guangdong Provincial Key Laboratory of Extreme Conditions(Grant No.2023B1212010002)+1 种基金the Micro-Raman Spectroscopy System(https://cstr.cn/31125.02.SHMFF.RAMAN)at the Steady High Magnetic Field Facility,CAS(https://cstr.cn/31125.02.SHMFF),for providing technical support and assistance in data collection and analysisthe beam time granted by J-PARC。
文摘The family of transition-metal dipnictides,MX2(M:metal,X:N,P,As,Sb,and Bi),has emerged as an important quantum material system due to its unique physical properties,such as large magnetoresistance,colossal Seebeck coefficients,and Weyl semimetal characteristics.In order to study the M-site ions effect on the lattice structure and the related dynamics,we compared two isostructural compounds,FeSb_(2)and RuSb_(2).Neutron diffraction,specific heat,and Raman scattering spectra of RuSb_(2)were measured.We found that the thermal expansion coefficients are isotropic for RuSb_(2),in contrast to the anisotropic behavior reported previously in FeSb_(2).Moreover,the specific heat of RuSb_(2)shows a bosonlike anomaly around 25 K.Four of the six predicted vibrational modes were identified by polarized Raman scattering spectra and successfully simulated by ab initio calculations.Meanwhile,the temperature-dependent linewidths reveal that phonon-phonon interactions might dominate above 50 K,while electron-phonon coupling remains relatively weak.
基金supported by the National Key R&D Program of China(No.2021YFB3501303)the National Natural Science Foundation of China(Nos.52122106 and U23A20547)+2 种基金the"Pioneer"R&D Program of Zhejiang Province(No.2022C01230)Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2021SZ-FR005)the Space Application System of China Manned Space Program(No.KJZ-YY-NCL03).
文摘The prevalence of wide-bandgap semiconductors urges the development of advanced soft magnetic materials for high-frequency applications.While soft magnetic alloys are limited by resonances at elevated frequencies,the incorporation of planar anisotropy serves as an effective strategy to overcome this dilemma and extend their potential for high-frequency applications.Herein,nanocrystalline Y_(2)Co_(14)B alloys have been designed with tuned magnetocrystalline and shape bi-anisotropy via melt spinning and magnetic field-assisted annealing.With the application of zero,transverse,rotational and longitudinal magnetic fields(denoted as ZFA,TFA,RFA and LFA),the effects of field direction and annealing time on microstructural and performance evolution have been investigated.Compared with ZFA,magnetic field-assisted annealing not only promotes the growth of nanograins but also alters the coincidence degree between intrinsic easy-plane(IEP)and artificial easy-plane(AEP)structures.While the random distribution of IEP structure is achieved for the RFA due to the formation of non-orientated nanograins,directional magnetic field-assisted annealing contributes to preferentially orientated(006)nanograins,especially for the LFA,resulting in optimal coincidence between the magnetocrystalline anisotropy and shape anisotropy.Such enhancement facilitates the transformation of magnetic domain structures into in-plane configurations with strip-like features.Consequently,a large ratio between the out-of-plane and in-plane anisotropy(H_(out)/H_(in))and improved softness of the alloy can be achieved,providing valuable references for future fabrication of rare-earth(R)transition-metal(T)alloys with superior easy-plane characteristics.
基金supported by the National Natural Science Foundation of China(Grant Nos.12174285 and 12474315)support from the National Natural Science Foundation of China(Grant No.62375200)+2 种基金support from the National Natural Science Foundation of China(Grant No.12504372)the China Postdoctoral Science Foundation-Tianjin Joint Support Program(Grant No.2025T003TJ)support from the National Natural Science Foundation of China(Grant No.12404424)。
文摘Two-dimensional(2D)transition-metal dichalcogenide(TMD)monolayers based on become a promising platform to study photonics and optoelectronics.Electrically controlling the excitonic properties of TMD monolayers can be realized in different devices.In this work,we realize the strong coupling between the excitons of WS_(2)monolayers and a photonic cavity mode in a liquid crystal microcavity.The formed exciton polaritons can be electrically tuned by applying voltage to the microcavity.Our work offers a way to study exciton-polariton manipulation based on TMD monolayers by electrical methods at room temperature.
基金partly supported by the National Natural Science Foundation of China(Nos.12275189 and 11705015)Natural Science Foundation of the Jiangsu Higher Education Institutions(No.23KJA430001)Collaborative Innovation Center of Suzhou Nano Science&Technology。
文摘P2-type layered transition-metal oxides with high energy density and rich variety have attracted extensive attention for sodium-ion batteries(SIBs)in grid-scale energy storage application,but they usually suffer from sluggish kinetics and large volume change upon cycling.Herein,we designed a highperformance P2-type Na_(0.67)Ni_(0.31)Mn_(0.67)Mo_(0.02)O_(2)(NNMMO)cathode with regulated electronic environment and Na^(+)zigzag ordering modulation via high-valence Mo6+stabilization engineering.The achieved NNMMO cathode exhibits a high-rate capability with a reversible capacity of 77.2 m Ah/g at 10 C and a long cycle life with a capacity retention of 75%at 2 C after 1000 cycles.In addition,in situ X-ray diffraction and ex-situ X-ray absorption fine structure spectroscopy characterizations verify that the presence of Mo^(6+)also stabilizes the desodiated structure through a pinning effect,achieving an extremely low volume change of 1.04%upon Na^(+)extraction.The quantified diffusional analysis and theoretical calculations demonstrate that the Mo^(6+)-doping improves the Na+diffusion kinetics,optimizes the energy band structure and enhances the TM-O bond strength.Additionally,the as-fabricated pouch cells by paring NNMMO cathode and hard carbon anode show impressive cycling stability with an energy density of 296.7 Wh/kg.This study broadens the perspective for high-valence metal ion doping to obtain superior cathode materials and pave the way for developing high-energy-density SIBs.
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.
