The electrochemical CO_(2) reduction(ECR)into value-added products presents an appealing approach to mitigate CO_(2) emission caused by excess consumption of fossil fuels.To obtain high catalytic activity and selectiv...The electrochemical CO_(2) reduction(ECR)into value-added products presents an appealing approach to mitigate CO_(2) emission caused by excess consumption of fossil fuels.To obtain high catalytic activity and selectivity toward target product in ECR,designing and developing a stable and efficient electrocatalyst is of significant importance.To date,metal nanomaterials have been widely applied as electrocatalysts for ECR due to their unique physicochemical properties.The structural modulation of metal nanomaterials is an attractive strategy to improve the catalytic performance.In this review,the recent progress of structural modulation,including size,facet,grain boundary,composition,interface,ligand modification,and crystal phase,is systematically summarized from both theoretical and experimental aspects.Finally,the opportunities and perspectives of structural modulation of metal nanomaterials for ECR are proposed.展开更多
As a promising cathode material for sodium ion batteries,honeycomb-ordered layered Na_(3)Ni_(2)Sb O_(6)still suffers from rapid capacity fading because of partially irreversible phase transition.Herein,a substitution ...As a promising cathode material for sodium ion batteries,honeycomb-ordered layered Na_(3)Ni_(2)Sb O_(6)still suffers from rapid capacity fading because of partially irreversible phase transition.Herein,a substitution of Na+by Rb+with a larger ionic radius in honeycomb layered Na_(3)-xRbxNi_(2)Sb O_(6)is proposed to modulate the interlayer structure.The results unveil that biphasic transition reversibility of the intermediate P′3phase is substantially enhanced,and the structure evolution behavior during the charge/discharge process changes due to the structural modulation,which contributes to a suppression of the unfavorable O_(1)phase and an alleviation of the lattice distortion.Moreover,Rb substituted samples exhibited an improved Na+(de)intercalation thermodynamics and kinetics.Attributed to the modifications,the sample with optimized Rb content delivers superior cycle stability and rate capacity,demonstrating a feasible strategy for suppressing irreversible phase transition and developing high-performance honeycomb layered materials for sodium ion batteries.展开更多
Transmission electron microscopy （TEM） study of SrPt2As2 reveals two incommensurate modulations appearing in the charge-density-wave （CDW） state below TCDW ≈ 470 K. These two structural modulations can be well ex...Transmission electron microscopy （TEM） study of SrPt2As2 reveals two incommensurate modulations appearing in the charge-density-wave （CDW） state below TCDW ≈ 470 K. These two structural modulations can be well explained in terms of condensations of two-coupled phonon modes with wave vectors of q1=0.62a＊ on the a＊-b＊ plane and q2 = 0.23a＊ on the a＊-c＊ plane. The atomic displacements occur along the b-axis direction for q1 and along the c-axis direction for q2, respectively. Moreover, the correlation between ql and q2 can be generally written as q1 = （q2 ＋ a＊）/2 in the CDW state, suggesting the presence of essential coupling between q1 and q2. A small fraction of Ir doping on the Pt site in Sr（Pt1-xIrx）2As2 （x ≤ 0.06） could moderately change these CDW modulations and also affect their superconductivities.展开更多
Recently,many lead-free metal halides with diverse structures and highly efficient emission have been reported.However,their poor stability and single-mode emission color severely limit their applications.Herein,three...Recently,many lead-free metal halides with diverse structures and highly efficient emission have been reported.However,their poor stability and single-mode emission color severely limit their applications.Herein,three homologous Sb^(3+)-doped zero-dimensional(0D)air-stable Sn(IV)-based metal halides with different crystal structures were developed by inserting a single organic ligand into SnCl_(4)lattice,which brings different optical properties.Under photoexcitation,(C_(25)H_(22)P)SnC_(l5)@Sb⋅CH_(4O)(Sb^(3+)−1)does not emit light,(C_(25)H_(22)P)_(2)SnC_(l6)@Sb-α(Sb^(3+)−2α)shines bright yellow emission with a photoluminescence quantum yield(PLQY)of 92%,and(C_(25)H_(22)P)_(2)SnC_(l6)@Sb-β(Sb^(3+)−2β)exhibits intense red emission with a PLQY of 78%.The above three compounds show quite different optical properties should be due to their different crystal structures and the lattice distortions.Particularly,Sb^(3+)−1 can be successfully converted into Sb^(3+)−2αunder the treatment of C_(25)H_(22)PCl solution,accompanied by a transition from nonemission to efficient yellow emission,serving as a“turn-on”photoluminescence(PL)switching.Parallelly,a reversible structure conversion between Sb^(3+)−2αand Sb^(3+)−2βwas witnessed after dichloromethane or volatilization treatment,accompanied by yellow and red emission switching.Thereby,a triple-mode tunable PL switching of off-onI-onII can be constructed in Sb^(3+)-doped Sn(IV)-based compounds.Finally,we demonstrated the as-synthesized compounds in fluorescent anticounterfeiting,information encryption,and optical logic gates.展开更多
P2-type layered oxide,Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2),has drawn particular interest as a promising cathode material for sodium-ion batteries(SIBs)due to its fast sodium-ion transport channels with low migration potentia...P2-type layered oxide,Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2),has drawn particular interest as a promising cathode material for sodium-ion batteries(SIBs)due to its fast sodium-ion transport channels with low migration potential.However,some catastrophic flaws,such as air instability,complicated multiphase evolution,and irreversible anionic redox,limit its electrochemical performance and hinder its application.Here,an air-stable single-crystal P2-type Na_(2/3)Ni_(1/3)Mn_(1/3)Ti_(1/3)O_(2)is proposed based on the multifunctional structural modulation of Ti substitution that could alleviate the issues for practical SIBs.As a result,the cathode with high energy density shows excellent air stability and highly reversible phase transitions(P2–OP4),and delivers faster kinetics and stable anion redox chemistry.Meanwhile,a thorough investigation of the relationship between structure,function,and properties is demonstrated,emphasizing formation processes,electrochemical behavior,structural evolution,and air stability.Overall,this study provides the direction of multifunctional structural modulation for the development of high-performance sodium-based layered cathode materials for practical applications.展开更多
Polyvinyl chloride is the most widely used general-purpose plastic and plays a vital role in various industries.Mercury-based catalysts severely limit the green sustainability of industry.Non-metallic carbon materials...Polyvinyl chloride is the most widely used general-purpose plastic and plays a vital role in various industries.Mercury-based catalysts severely limit the green sustainability of industry.Non-metallic carbon materials are very promising alternatives in acetylene hydrochlorination,but their stability remains a challenge of major concern at present.Based on the principle of green chemistry,structurally tunable and defect-rich carbon materials were synthesized by hydrothermal carbonization and pyrolysis using glucose as carbon source and m-phenylenediamine as nitrogen source and cross-linking agent.Experimental characterization and density functional theory confirmed that pyridinic N was the main active site.The introduction of N not only regulated the formation of the hierarchically porous structure of the carbon material,but also increased the adsorption of HCl and decreased the adsorption strength of C_(2)H_(2).The synergistic effect of high N content and porous structure significantly enhanced the catalytic performance of the catalysts in acetylene hydrochlorination.The C_(2)H_(2)conversion was maintained at around98%after 100 h under the reaction conditions(T=220°C,GHSV(C_(2)H_(2))=30 h^(-1),V_(HCl)/VC_(2)H_(2)=1.15).Thus,the one-pot synthesis process used here is a good benchmark for future catalyst research.展开更多
Concise chemistry leads to a family of heptanuclear Co^(Ⅱ)-clusters,[Co_(7)(N_(3))_(12)(CH_(3)CN)_(12)][Y_(2)(NO_(3))_(4)(piv)_(4)]·2CH_(3)CN(DC1)(pivH=pivalic acid),[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(0...Concise chemistry leads to a family of heptanuclear Co^(Ⅱ)-clusters,[Co_(7)(N_(3))_(12)(CH_(3)CN)_(12)][Y_(2)(NO_(3))_(4)(piv)_(4)]·2CH_(3)CN(DC1)(pivH=pivalic acid),[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(0.4)(Cl)_(1.6)]·4CH_(3)CN(DC2)and[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(2)]·4CH_(3)CN(DC3),in which the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology.The resulting clusters exhibit interesting structural transformations and thermodynamically-distinct steady states verified by theoretical calcula-tions.Magnetic studies reveal the first observation of zero-field SMM behaviour in disk-like heptanuclear Co^(Ⅱ)complexes.展开更多
Metal halide perovskites possess appealing optoelectronic properties and have been widely applied for solar energy harvesting and light emitting.Although perovskite solar cells(PeSCs)and perovskite light-emitting diod...Metal halide perovskites possess appealing optoelectronic properties and have been widely applied for solar energy harvesting and light emitting.Although perovskite solar cells(PeSCs)and perovskite light-emitting diodes(PeLEDs)have been developed rapidly in recent years,there are still no universal rules for the selection of perovskites to achieve high-performance optoelectronic devices.In this review,the working mechanisms of PeSCs and PeLEDs are first demonstrated with the discussion on the factors which determine the device performance.We then examine the optoelectronic properties of perovskites with structures modulated from 3D,2D,1D to 0D,and analyze the corresponding structure-property relationships in terms of photo-electric and electric-photo conversion processes.Based on the unique optoelectronic properties of structurally modulated perovskites,we put forward the concept of structural assembling engineering that integrate the merits of different types of perovskites within one matrix and elaborate their excellent properties for applications of both PeSCs and PeLEDs.Finally,we discuss the potential challenges and provide our perspectives on the structural assembling engineering of perovskites for future optoelectronic applications.展开更多
The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various field...The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.展开更多
The sluggish electrochemical catalytic activity of the graphite felt electrodes for anode reaction is still a barrier for achieving high-performance vanadium redox flow battery(VRFB).It is significant to leverage the ...The sluggish electrochemical catalytic activity of the graphite felt electrodes for anode reaction is still a barrier for achieving high-performance vanadium redox flow battery(VRFB).It is significant to leverage the exceptional conductivity,excellent electrocatalytic activity,and structural tunability of MXene to address this issue.Herein,this work introduces nitrogen atoms to modulate the carbon layer structure of Ti_(3)C_(2)T_(x)MXene,inducing a reconfiguration of the local electronic structure,which enhances the anode interface activity and thereby improves the performance of VRFB.Ti_(3)C_(2)T_(x)exhibits high conductivity,excellent hydrophilicity,and a large specific surface area,providing excellent interface characteristics for V^(3+)/V^(2+)redox reaction.Moreover,interlayer treatment to modulate the mesoporous structure of MXene further increases the reactive surface area.Importantly,doping nitrogen atoms at carbon layer induces lattice distortions in Ti_(3)C_(2)T_(x),which enhances the charge transfer processes of the V^(3+)/V^(2+)redox reaction.The catalysis mechanism is also validated through density functional theory.Furthermore,the modified graphite felt electrode,as the anode of VRFB,relieves a higher energy efficiency of 68%at 250 mA cm^(-2),while the pristine electrode cannot operate at this current density.In addition,at 150 mA cm^(-2),the modified battery maintains energy efficiency at 75%without degradation after 500 cycles.This study utilizes rational atomic-level engineering for effective structural modulation to significantly enhance the catalytic activity of electrode reaction,offering a unique perspective for developing high-performance MXene electrocatalysts of VRFB.展开更多
Precise regulation of atomic and electronic structures of two-dimensional tungsten disulfide(WS_(2))is significant for rational design of high-performance and low-cost catalyst for acetylene hydrogenation to ethylene(...Precise regulation of atomic and electronic structures of two-dimensional tungsten disulfide(WS_(2))is significant for rational design of high-performance and low-cost catalyst for acetylene hydrogenation to ethylene(AHE),yet remains a major challenge.Herein,we report that by substituting a W atom of WS_(2) with a series of transition metal atoms,sulfur vacancy-confined Cu in the WS_(2) basal plane(Cu@WS_(2)-Sv)is theoretically screened as a superior non-noble metal-based catalyst with higher activity,selectivity,and stability for the AHE than other candidates.The co-adsorption of C_(2)H_(2) and H_(2) and hydrogenation of C_(2)H_(3)^(*) to C_(2)H_(4)^(*) are revealed as the key steps establishing a volcano-like activity trend among the candidates,which present Cu@WS_(2)-Sv as the optimum catalyst combined with molecular dynamics and reaction kinetics analyses.The kinetically more favorable desorption of C_(2)H_(4) than the over hydrogenation path validates a higher selectivity toward C_(2)H_(4) over C_(2)H_(6).Furthermore,a machine-learning model reveals the significant effect of d-electron number and electronegativity of the metal heteroatoms in modulating the AHE activity.展开更多
Construction of elaborate configuration to enhance the intrinsic activity of NiMo-based catalyst candidates holds promise for accelerating the hydrogen evolution reaction(HER)kinetics.Herein,a novel cerium-doped NiMo ...Construction of elaborate configuration to enhance the intrinsic activity of NiMo-based catalyst candidates holds promise for accelerating the hydrogen evolution reaction(HER)kinetics.Herein,a novel cerium-doped NiMo phosphate(labeled as Ce-NiMo(PO_(4))_(0.66))is designed and fabricated via a facile hydrothermal and phosphatization method.A comprehensive characterization reveals that the introduction of the rare metal element cerium with an enriched 4f electronic distribution near the Fermi level modulates the hybridization of the 3d-2p orbitals and optimizes the electronic structure of the NiMo-based phosphate catalysts,which leads to the synergy between the nickel-molybdenum dual sites and the phosphate active unit to synchronously enhance the water dissociation and proton dehydrogenation transfer of the HER process.Consequently,Ce-NiMo(PO_(4))0.66 exhibits excellent alkaline HER performance with overpotentials at 10 and 500 mA·cm^(-2)current densities being only 40 and 295 mV,respectively,and desirable long-term durability at industrial current densities of 500 mA·cm^(-2).An overall hydrazine splitting(OHzS)constructed with Ce-NiMo(PO_(4))_(0.66)as a hydrazine oxidation reaction(HzOR)and HER bifunctional electrocatalyst has been constructed to achieve industrial current densities at the low voltage of 0.92 V,verifying its practical feasibility for sustainable hydrogen production and degradation of hydrazine pollutants.This work highlights that regulating the 3d-2p hybridization state through the inducing 4f orbital electronic state is a feasible means for enhancing the HER activity of transition metal compound catalysts.展开更多
Advancing aqueous zinc-ion batteries(AZIBs)are significantly challenged by the need to find cathode materials that can provide both high capacity and fast reaction kinetics.Tellurium telluride,a topological insulator,...Advancing aqueous zinc-ion batteries(AZIBs)are significantly challenged by the need to find cathode materials that can provide both high capacity and fast reaction kinetics.Tellurium telluride,a topological insulator,has emerged as a promising cathode candidate for AZIBs,garnering increasing attention.However,the complete understanding of its electrochemical reaction mechanism and its unsatisfactory energy storage performance are major obstacles to the practical use.In this work,we synthesize a bimetallic bismuth-nickel telluride with Te vacancies,defined as Bi_(2)Te_(3-x)/NiTe_(2),which forms a topological insulator/topological Dirac semimetal heterostructure through a hydrothermal approach.The electrochemical reaction mechanism of Bi_(2)Te_(3-x)/NiTe_(2),along with its phase and structural changes are elucidated by using in-situ X-ray diffraction,various electrochemical techniques,and ex-situ characterizations.The influences of Bi_(2)Te_(3-x)/NiTe_(2)on the electronic structure,interracial electron transfer,migration barrier,and ion adsorption energy are investigated by using density functional theory calculations.Our findings reveal that Bi_(2)Te_(3-x)/NiTe_(2)exhibits excellent specific capacity,stable cycling,and superior rate capability as a cathode material for AZIBs.Moreover,further studies demonstrate that Bi_(2)Te_(3-x)/NiTe_(2)maintains exceptional performance at low temperatures of-15 and-5℃,and also retains stability and flexibility when integrated into flexible battery packs.展开更多
Significant two-way shape memory effect(TWSME)was achieved in single crystals of single-phase multielement Ni42-x Cu8 Cox Mn37 Ga13(8≤x≤12)alloys by performing thermomechanical training.However,anomalous dependence ...Significant two-way shape memory effect(TWSME)was achieved in single crystals of single-phase multielement Ni42-x Cu8 Cox Mn37 Ga13(8≤x≤12)alloys by performing thermomechanical training.However,anomalous dependence of the martensitic transformation temperature span on Co content was observed.Before training,quite a narrow temperature span of the martensitic transformation,nearly independent of the Co content,was observed in all single crystals.After training the temperature span was still narrow for 8≤x≤10.9 but was obviously expanded for 10.9<x≤12.High-resolution transmission electron microscopy revealed that at the atomic scale,there exists incommensurate modulated structure in the single phase single crystals,as evidenced by nonperiodic satellite spots in the selected area electronic diffraction patterns.Moreover,the modulated wave vector of the satellite spots was increased by higher Co contents.Combining first principal calculations it was considered that the incommensurate modulated structure originates from the formation of Co-Co pairs.After training arrays of ordered dislocations with the same Burgers vector were introduced for 8≤x≤10.9 but the network of dislocations was formed for 10.9<x≤12.Based on analysis of transmission electron microscopy,geometric phase,thermodynamics,and Landau theory,it was considered that the austenite/martensite phase interface was pinned by the network of dislocations,expanding the temperature span of the martensitic transformation.This work supplies new insights for understanding the microstructure and martensitic transformation of Ni-Mn-Ga-based alloys.展开更多
Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical...Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical”compressive pressure through cation substitution is still limited.Here,we address this issue in the La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,1.5,2.0,and 2.5)thin film samples.It was found that using Nd3+with a smaller radius instead of La3+can reduce the c-axis lattice constant and shift the metal-insulator transition(MIT)temperature TMIT.To probe the origin of the MIT at cryogenic temperatures,experimental measurements of magnetoresistance were conducted,and theoretical analysis was carried out using the Kondo model,Hikami-Larkin-Nagaoka equation,and other methods.The results indicate that as Nd doping rises,the contributions of the Kondo effect and two-dimensional weak localization(WL)first decrease and then increase.The total contribution of WL and the Kondo effect in the mid-doped La_(1.5)Nd_(1.5)Ni_(2)O_(7)sample was the smallest,which to some extent explains the changes in TMIT.The Kondo effect dominates in other La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,2.0,and 2.5)samples.This work demonstrates that cation doping has a significant impact on bilayer nickelates,providing experimental evidence for understanding the physical mechanism of the MIT in bilayer nickelates.展开更多
The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Eff...The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Effectively regulating the electronic structure of Pt to enhance CO resistance is crucial for developing high-performance catalysts with robust anti-poisoning capabilities.Herein,the Pt/W@NCNF featured by Pt nanoparticles and atomical dispersed tungsten(W)sites on N-doped carbon nanofibers is developed for CO tolerance HOR catalyst.The presence of W enables the electron transfer from Pt,which promotes electron rearrangement in the Pt-5d orbitals.It not only optimizes the adsorption of H^(*) and CO^(*)on Pt,but also the OH^(*) intermediates adsorbed on the W sites oxidize the CO*adsorbed on Pt,thereby retaining more active sites for H_(2) adsorption and oxidation.The HOR exchange current density of Pt/W@NCNF reaches 1.35 times that of commercial Pt/C,and the limiting current density decreases by only 3.4%after introducing 1000 ppm CO in H_(2).Notably,the Pt/W@NCNF-based PEMFCs deliver markedly superior performance across a range of CO concentrations.The present study demonstrates that electronic modulation of Pt is an effective strategy for simultaneously achieving resistance to CO and promoted HOR activity.展开更多
Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four plan...Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.展开更多
C1 chemistry is the essence of coal chemistry and natural gas chemistry. Catalytic methods to efficiently convert C1 molecules into fuels and chemicals have been extensively studied. Syngas（CO ＋H_2） conversion is t...C1 chemistry is the essence of coal chemistry and natural gas chemistry. Catalytic methods to efficiently convert C1 molecules into fuels and chemicals have been extensively studied. Syngas（CO ＋H_2） conversion is the most important industrial reaction system in C1 chemistry, and Fe and Co catalysts, two major industrial catalysts, have been the focus of fundamental research and industrial application. In the last decade, considerable research efforts have been devoted to discoveries concerning catalyst structure and increasing market demands for olefins and oxygenates. Since the development of efficient catalysts would strongly benefit from catalyst design and the establishment of a new reaction system, this review comprehensively overviews syngas conversion in three main reactions, highlights the advances recently made and the challenges that remain open, and will stimulate future research activities. The first part of the review summarizes the breakthroughs in Fischer-Tropsch synthesis regarding the optimization of activity and stability, determination of the active phase, and mechanistic studies. The second part overviews the modulation of catalytic structure and product selectivity for Fischer-Tropsch to olefins（FTO）. Catalysts designed to produce higher alcohols, as well as to tune product selectivity in C1 chemistry, are described in the third section. Finally, present challenges in syngas conversion are proposed, and the solutions and prospects are discussed from the viewpoint of fundamental research and practical application. This review summarizes the latest advances in the design, preparation, and application of Fe/Co-based catalysts toward syngas conversion and presents the challenges and future directions in producing value-added fuels.展开更多
Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanopart...Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanoparticles(diameter:6±2 nm)are homogeneously immobilized on 2D Ni based MOFs(Ni-BDC,thickness:5±1 nm)to improve the OER stability.Electronic structure modulation for enhanced catalytic activity is studied via adjusting the amount of Fe_(3)O_(4) nanoparticles on Ni-BDC.The optimal Fe_(3)O_(4)/Ni-BDC achieves the best OER performance with an overpotential of 295 mV at 10 mA cm^(-2),a Tafel slope of 47.8 mV dec^(-1) and a considerable catalytic durability of more than 40 h(less than 5 h for Ni-BDC alone).DFT calculations confirm that the active sites for Fe_(3)O_(4)/Ni-BDC are mainly contributed by Fe species with a higher oxidation state,and the potential-determining step(PDS)is the formation of the adsorbed O*species,which are facilitated in the composite.展开更多
With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the...With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the current issue to focus on consideration. Therefore, this paper will focus on the design method of multi-layer steel structure module and steel frame composite building structure, and analyze and study its structure, so as to improve the utilization rate of steel structure and promote the development of the construction industry.展开更多
基金financially supported by the National Key R&D Program(N os.2017 YF A0204503 and 2016YFB0401100)the National Natural Science Foundation of China(Nos.91833306,21875158,51633006 and 51703159)。
文摘The electrochemical CO_(2) reduction(ECR)into value-added products presents an appealing approach to mitigate CO_(2) emission caused by excess consumption of fossil fuels.To obtain high catalytic activity and selectivity toward target product in ECR,designing and developing a stable and efficient electrocatalyst is of significant importance.To date,metal nanomaterials have been widely applied as electrocatalysts for ECR due to their unique physicochemical properties.The structural modulation of metal nanomaterials is an attractive strategy to improve the catalytic performance.In this review,the recent progress of structural modulation,including size,facet,grain boundary,composition,interface,ligand modification,and crystal phase,is systematically summarized from both theoretical and experimental aspects.Finally,the opportunities and perspectives of structural modulation of metal nanomaterials for ECR are proposed.
基金funded by the NSFC Grant(52177213)supported through NSFC Committee of Chinathe foundation(2020A1414010346 and 2019622163008)supported through the Science and Technology Bureau of Guangdong Governmentsponsored by the Student Research Program(X202110561688)supported through South China University of Technology。
文摘As a promising cathode material for sodium ion batteries,honeycomb-ordered layered Na_(3)Ni_(2)Sb O_(6)still suffers from rapid capacity fading because of partially irreversible phase transition.Herein,a substitution of Na+by Rb+with a larger ionic radius in honeycomb layered Na_(3)-xRbxNi_(2)Sb O_(6)is proposed to modulate the interlayer structure.The results unveil that biphasic transition reversibility of the intermediate P′3phase is substantially enhanced,and the structure evolution behavior during the charge/discharge process changes due to the structural modulation,which contributes to a suppression of the unfavorable O_(1)phase and an alleviation of the lattice distortion.Moreover,Rb substituted samples exhibited an improved Na+(de)intercalation thermodynamics and kinetics.Attributed to the modifications,the sample with optimized Rb content delivers superior cycle stability and rate capacity,demonstrating a feasible strategy for suppressing irreversible phase transition and developing high-performance honeycomb layered materials for sodium ion batteries.
基金Project supported by the National Basic Research Program of China(Grant Nos.2011CBA00101,2010CB923002,2012CB821404,and 2011CB921703)the National Natural Science Foundation of China(Grant Nos.11190022,11274368,and 51272277)the Funds from the Chinese Academy of Sciences
文摘Transmission electron microscopy （TEM） study of SrPt2As2 reveals two incommensurate modulations appearing in the charge-density-wave （CDW） state below TCDW ≈ 470 K. These two structural modulations can be well explained in terms of condensations of two-coupled phonon modes with wave vectors of q1=0.62a＊ on the a＊-b＊ plane and q2 = 0.23a＊ on the a＊-c＊ plane. The atomic displacements occur along the b-axis direction for q1 and along the c-axis direction for q2, respectively. Moreover, the correlation between ql and q2 can be generally written as q1 = （q2 ＋ a＊）/2 in the CDW state, suggesting the presence of essential coupling between q1 and q2. A small fraction of Ir doping on the Pt site in Sr（Pt1-xIrx）2As2 （x ≤ 0.06） could moderately change these CDW modulations and also affect their superconductivities.
基金Guangxi Graduate Education,Grant/Award Number:YCSW2023026Scientific and Technological Bases and Talents of Guangxi,Grant/Award Numbers:AD23026119,AD21238027Guangxi NSF project,Grant/Award Number:2020GXNSFDA238004。
文摘Recently,many lead-free metal halides with diverse structures and highly efficient emission have been reported.However,their poor stability and single-mode emission color severely limit their applications.Herein,three homologous Sb^(3+)-doped zero-dimensional(0D)air-stable Sn(IV)-based metal halides with different crystal structures were developed by inserting a single organic ligand into SnCl_(4)lattice,which brings different optical properties.Under photoexcitation,(C_(25)H_(22)P)SnC_(l5)@Sb⋅CH_(4O)(Sb^(3+)−1)does not emit light,(C_(25)H_(22)P)_(2)SnC_(l6)@Sb-α(Sb^(3+)−2α)shines bright yellow emission with a photoluminescence quantum yield(PLQY)of 92%,and(C_(25)H_(22)P)_(2)SnC_(l6)@Sb-β(Sb^(3+)−2β)exhibits intense red emission with a PLQY of 78%.The above three compounds show quite different optical properties should be due to their different crystal structures and the lattice distortions.Particularly,Sb^(3+)−1 can be successfully converted into Sb^(3+)−2αunder the treatment of C_(25)H_(22)PCl solution,accompanied by a transition from nonemission to efficient yellow emission,serving as a“turn-on”photoluminescence(PL)switching.Parallelly,a reversible structure conversion between Sb^(3+)−2αand Sb^(3+)−2βwas witnessed after dichloromethane or volatilization treatment,accompanied by yellow and red emission switching.Thereby,a triple-mode tunable PL switching of off-onI-onII can be constructed in Sb^(3+)-doped Sn(IV)-based compounds.Finally,we demonstrated the as-synthesized compounds in fluorescent anticounterfeiting,information encryption,and optical logic gates.
基金supported by the National Natural Science Foundation of China(52250710680,51971124,52171217,52202284)Hunan Provincial Science and Technology Innovation Major Project(2020GK1010-2020GK1014-4)+7 种基金Zhejiang Provincial Natural Science Foundation(LZ21E010001,LQ23E020002)Science and Technology Project of State Grid Corporation of China(5419-202158503A-0-5-ZN)Wenzhou key scientific and technological innovation research projects(ZG2023053)Wenzhou Natural Science Foundation(ZG2022032,G20220019,G20220021)Cooperation between industry and education project of Ministry of Education(220601318235513)State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University(EIPE22208)the China Scholarship Council(202106370062)Doctoral Innovation Foundation of Wenzhou University(3162023001001)。
文摘P2-type layered oxide,Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2),has drawn particular interest as a promising cathode material for sodium-ion batteries(SIBs)due to its fast sodium-ion transport channels with low migration potential.However,some catastrophic flaws,such as air instability,complicated multiphase evolution,and irreversible anionic redox,limit its electrochemical performance and hinder its application.Here,an air-stable single-crystal P2-type Na_(2/3)Ni_(1/3)Mn_(1/3)Ti_(1/3)O_(2)is proposed based on the multifunctional structural modulation of Ti substitution that could alleviate the issues for practical SIBs.As a result,the cathode with high energy density shows excellent air stability and highly reversible phase transitions(P2–OP4),and delivers faster kinetics and stable anion redox chemistry.Meanwhile,a thorough investigation of the relationship between structure,function,and properties is demonstrated,emphasizing formation processes,electrochemical behavior,structural evolution,and air stability.Overall,this study provides the direction of multifunctional structural modulation for the development of high-performance sodium-based layered cathode materials for practical applications.
基金supported by the Tianchi Innovation Leading Talent Development Fund(No.CZ002710)in Xinjiangthe Taishan Scholars Program of Shandong Province(No.tsqn202103051)+4 种基金the Project of Science and Technology Development of Yantai City(No.2023JCYJ073)Natural science foundation of Shandong province(No.ZR2023MB064)special funds for over provincial level leading talent of Yantai citythe Start-Up Foundation for High-level Professionals of Shihezi University(No.RCZK201932)Tianshan Talents Training Program of Xinjiang(Science and Technology Innovation Team,No.2022TSYCTD0021)。
文摘Polyvinyl chloride is the most widely used general-purpose plastic and plays a vital role in various industries.Mercury-based catalysts severely limit the green sustainability of industry.Non-metallic carbon materials are very promising alternatives in acetylene hydrochlorination,but their stability remains a challenge of major concern at present.Based on the principle of green chemistry,structurally tunable and defect-rich carbon materials were synthesized by hydrothermal carbonization and pyrolysis using glucose as carbon source and m-phenylenediamine as nitrogen source and cross-linking agent.Experimental characterization and density functional theory confirmed that pyridinic N was the main active site.The introduction of N not only regulated the formation of the hierarchically porous structure of the carbon material,but also increased the adsorption of HCl and decreased the adsorption strength of C_(2)H_(2).The synergistic effect of high N content and porous structure significantly enhanced the catalytic performance of the catalysts in acetylene hydrochlorination.The C_(2)H_(2)conversion was maintained at around98%after 100 h under the reaction conditions(T=220°C,GHSV(C_(2)H_(2))=30 h^(-1),V_(HCl)/VC_(2)H_(2)=1.15).Thus,the one-pot synthesis process used here is a good benchmark for future catalyst research.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21863009,22063008)the Natural Science Foundation of Ningxia Province(Nos.2023AAC03014,2023AAC03227,2021AAC03136,2021BEB04062)+1 种基金the Young Top-notch Talent Cultivation Program of Ningxia Province,the Discipline Project of Ningxia(No.NXYLXK2017A04)the China Postdoctoral Science Foundation(No.2022M723148).
文摘Concise chemistry leads to a family of heptanuclear Co^(Ⅱ)-clusters,[Co_(7)(N_(3))_(12)(CH_(3)CN)_(12)][Y_(2)(NO_(3))_(4)(piv)_(4)]·2CH_(3)CN(DC1)(pivH=pivalic acid),[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(0.4)(Cl)_(1.6)]·4CH_(3)CN(DC2)and[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(2)]·4CH_(3)CN(DC3),in which the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology.The resulting clusters exhibit interesting structural transformations and thermodynamically-distinct steady states verified by theoretical calcula-tions.Magnetic studies reveal the first observation of zero-field SMM behaviour in disk-like heptanuclear Co^(Ⅱ)complexes.
基金Singapore Economic Development BoardEnergy Market Authority of Singapore+3 种基金National Research Foundation SingaporeNational University of SingaporeInternational Postdoctoral Exchange Fellowship Program(Talent-Introduction Program)of ChinaBoya Postdoctoral program of Peking University。
文摘Metal halide perovskites possess appealing optoelectronic properties and have been widely applied for solar energy harvesting and light emitting.Although perovskite solar cells(PeSCs)and perovskite light-emitting diodes(PeLEDs)have been developed rapidly in recent years,there are still no universal rules for the selection of perovskites to achieve high-performance optoelectronic devices.In this review,the working mechanisms of PeSCs and PeLEDs are first demonstrated with the discussion on the factors which determine the device performance.We then examine the optoelectronic properties of perovskites with structures modulated from 3D,2D,1D to 0D,and analyze the corresponding structure-property relationships in terms of photo-electric and electric-photo conversion processes.Based on the unique optoelectronic properties of structurally modulated perovskites,we put forward the concept of structural assembling engineering that integrate the merits of different types of perovskites within one matrix and elaborate their excellent properties for applications of both PeSCs and PeLEDs.Finally,we discuss the potential challenges and provide our perspectives on the structural assembling engineering of perovskites for future optoelectronic applications.
基金This work was supported by the National Natural Science Foundation of China(52372289,52102368,52072192 and 51977009)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905).
文摘The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.
基金financially supported by the National Natural Science Foundation of China(51872090,51772097)Hebei Natural Science Fund for Distinguished Young Scholar(E2019209433)+3 种基金Youth Talent Program of Hebei Provincial Education Department(BJ2018020)Natural Science Foundation of Hebei Province(E2020209151,E2024209029)National Key R&D Plan Project(2022YFB4200305)Research Projects of China National Petroleum Corporation(2024ZG50,2023DQ03-04)。
文摘The sluggish electrochemical catalytic activity of the graphite felt electrodes for anode reaction is still a barrier for achieving high-performance vanadium redox flow battery(VRFB).It is significant to leverage the exceptional conductivity,excellent electrocatalytic activity,and structural tunability of MXene to address this issue.Herein,this work introduces nitrogen atoms to modulate the carbon layer structure of Ti_(3)C_(2)T_(x)MXene,inducing a reconfiguration of the local electronic structure,which enhances the anode interface activity and thereby improves the performance of VRFB.Ti_(3)C_(2)T_(x)exhibits high conductivity,excellent hydrophilicity,and a large specific surface area,providing excellent interface characteristics for V^(3+)/V^(2+)redox reaction.Moreover,interlayer treatment to modulate the mesoporous structure of MXene further increases the reactive surface area.Importantly,doping nitrogen atoms at carbon layer induces lattice distortions in Ti_(3)C_(2)T_(x),which enhances the charge transfer processes of the V^(3+)/V^(2+)redox reaction.The catalysis mechanism is also validated through density functional theory.Furthermore,the modified graphite felt electrode,as the anode of VRFB,relieves a higher energy efficiency of 68%at 250 mA cm^(-2),while the pristine electrode cannot operate at this current density.In addition,at 150 mA cm^(-2),the modified battery maintains energy efficiency at 75%without degradation after 500 cycles.This study utilizes rational atomic-level engineering for effective structural modulation to significantly enhance the catalytic activity of electrode reaction,offering a unique perspective for developing high-performance MXene electrocatalysts of VRFB.
文摘Precise regulation of atomic and electronic structures of two-dimensional tungsten disulfide(WS_(2))is significant for rational design of high-performance and low-cost catalyst for acetylene hydrogenation to ethylene(AHE),yet remains a major challenge.Herein,we report that by substituting a W atom of WS_(2) with a series of transition metal atoms,sulfur vacancy-confined Cu in the WS_(2) basal plane(Cu@WS_(2)-Sv)is theoretically screened as a superior non-noble metal-based catalyst with higher activity,selectivity,and stability for the AHE than other candidates.The co-adsorption of C_(2)H_(2) and H_(2) and hydrogenation of C_(2)H_(3)^(*) to C_(2)H_(4)^(*) are revealed as the key steps establishing a volcano-like activity trend among the candidates,which present Cu@WS_(2)-Sv as the optimum catalyst combined with molecular dynamics and reaction kinetics analyses.The kinetically more favorable desorption of C_(2)H_(4) than the over hydrogenation path validates a higher selectivity toward C_(2)H_(4) over C_(2)H_(6).Furthermore,a machine-learning model reveals the significant effect of d-electron number and electronegativity of the metal heteroatoms in modulating the AHE activity.
基金supported by the National Natural Science Foundation of China(No.22278097)Heilongjiang Province Universities Basic Scientific Research Business Fee Project(Nos.2022-KYYWF-0568 and 2023-KYYWF-0527)+2 种基金the Natural Science Foundation of Heilongjiang Province(No.YQ2021B004)the Postdoctoral fellowship of Heilongjiang Province(No.LBH-Z23156)the Postdoctoral Fellowship Program of CPSF(No.GZC20233449).
文摘Construction of elaborate configuration to enhance the intrinsic activity of NiMo-based catalyst candidates holds promise for accelerating the hydrogen evolution reaction(HER)kinetics.Herein,a novel cerium-doped NiMo phosphate(labeled as Ce-NiMo(PO_(4))_(0.66))is designed and fabricated via a facile hydrothermal and phosphatization method.A comprehensive characterization reveals that the introduction of the rare metal element cerium with an enriched 4f electronic distribution near the Fermi level modulates the hybridization of the 3d-2p orbitals and optimizes the electronic structure of the NiMo-based phosphate catalysts,which leads to the synergy between the nickel-molybdenum dual sites and the phosphate active unit to synchronously enhance the water dissociation and proton dehydrogenation transfer of the HER process.Consequently,Ce-NiMo(PO_(4))0.66 exhibits excellent alkaline HER performance with overpotentials at 10 and 500 mA·cm^(-2)current densities being only 40 and 295 mV,respectively,and desirable long-term durability at industrial current densities of 500 mA·cm^(-2).An overall hydrazine splitting(OHzS)constructed with Ce-NiMo(PO_(4))_(0.66)as a hydrazine oxidation reaction(HzOR)and HER bifunctional electrocatalyst has been constructed to achieve industrial current densities at the low voltage of 0.92 V,verifying its practical feasibility for sustainable hydrogen production and degradation of hydrazine pollutants.This work highlights that regulating the 3d-2p hybridization state through the inducing 4f orbital electronic state is a feasible means for enhancing the HER activity of transition metal compound catalysts.
基金supported by the National Natural Science Foundation of China(No.52372223)the Science Foundation of Shaanxi Province(No.2023-JC-ZD-03 and 2022GD-TSLD-15)Shaanxi Fundamental Science Research Project for Mathematics and Physics(No.23JSQ005)。
文摘Advancing aqueous zinc-ion batteries(AZIBs)are significantly challenged by the need to find cathode materials that can provide both high capacity and fast reaction kinetics.Tellurium telluride,a topological insulator,has emerged as a promising cathode candidate for AZIBs,garnering increasing attention.However,the complete understanding of its electrochemical reaction mechanism and its unsatisfactory energy storage performance are major obstacles to the practical use.In this work,we synthesize a bimetallic bismuth-nickel telluride with Te vacancies,defined as Bi_(2)Te_(3-x)/NiTe_(2),which forms a topological insulator/topological Dirac semimetal heterostructure through a hydrothermal approach.The electrochemical reaction mechanism of Bi_(2)Te_(3-x)/NiTe_(2),along with its phase and structural changes are elucidated by using in-situ X-ray diffraction,various electrochemical techniques,and ex-situ characterizations.The influences of Bi_(2)Te_(3-x)/NiTe_(2)on the electronic structure,interracial electron transfer,migration barrier,and ion adsorption energy are investigated by using density functional theory calculations.Our findings reveal that Bi_(2)Te_(3-x)/NiTe_(2)exhibits excellent specific capacity,stable cycling,and superior rate capability as a cathode material for AZIBs.Moreover,further studies demonstrate that Bi_(2)Te_(3-x)/NiTe_(2)maintains exceptional performance at low temperatures of-15 and-5℃,and also retains stability and flexibility when integrated into flexible battery packs.
基金support from the National Key Research and Development Program of China(Grant No.2021YFB3501402)the National Natural Science Foundation of China(Grant Nos.52250313 and 52121001)Yang Liu and Chen Si acknowledge financial support from the National Natural Science Foundation of China(Grant No.12274013).
文摘Significant two-way shape memory effect(TWSME)was achieved in single crystals of single-phase multielement Ni42-x Cu8 Cox Mn37 Ga13(8≤x≤12)alloys by performing thermomechanical training.However,anomalous dependence of the martensitic transformation temperature span on Co content was observed.Before training,quite a narrow temperature span of the martensitic transformation,nearly independent of the Co content,was observed in all single crystals.After training the temperature span was still narrow for 8≤x≤10.9 but was obviously expanded for 10.9<x≤12.High-resolution transmission electron microscopy revealed that at the atomic scale,there exists incommensurate modulated structure in the single phase single crystals,as evidenced by nonperiodic satellite spots in the selected area electronic diffraction patterns.Moreover,the modulated wave vector of the satellite spots was increased by higher Co contents.Combining first principal calculations it was considered that the incommensurate modulated structure originates from the formation of Co-Co pairs.After training arrays of ordered dislocations with the same Burgers vector were introduced for 8≤x≤10.9 but the network of dislocations was formed for 10.9<x≤12.Based on analysis of transmission electron microscopy,geometric phase,thermodynamics,and Landau theory,it was considered that the austenite/martensite phase interface was pinned by the network of dislocations,expanding the temperature span of the martensitic transformation.This work supplies new insights for understanding the microstructure and martensitic transformation of Ni-Mn-Ga-based alloys.
基金supported by the Natural Science Foundation of Guangdong Province of China(Grant No.2025A1515011071)the National Natural Science Foundation of China(Grant Nos.92065110,11974048,and 12074334)the Beijing Municipal Natural Science Foundation Key Research Topics(Grant No.Z230006)。
文摘Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical”compressive pressure through cation substitution is still limited.Here,we address this issue in the La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,1.5,2.0,and 2.5)thin film samples.It was found that using Nd3+with a smaller radius instead of La3+can reduce the c-axis lattice constant and shift the metal-insulator transition(MIT)temperature TMIT.To probe the origin of the MIT at cryogenic temperatures,experimental measurements of magnetoresistance were conducted,and theoretical analysis was carried out using the Kondo model,Hikami-Larkin-Nagaoka equation,and other methods.The results indicate that as Nd doping rises,the contributions of the Kondo effect and two-dimensional weak localization(WL)first decrease and then increase.The total contribution of WL and the Kondo effect in the mid-doped La_(1.5)Nd_(1.5)Ni_(2)O_(7)sample was the smallest,which to some extent explains the changes in TMIT.The Kondo effect dominates in other La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,2.0,and 2.5)samples.This work demonstrates that cation doping has a significant impact on bilayer nickelates,providing experimental evidence for understanding the physical mechanism of the MIT in bilayer nickelates.
基金supported by the National Natural Science Foundation of China(22179034,22279030)the Natural Science Foundation of Heilongjiang Province(ZD2023B002).
文摘The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Effectively regulating the electronic structure of Pt to enhance CO resistance is crucial for developing high-performance catalysts with robust anti-poisoning capabilities.Herein,the Pt/W@NCNF featured by Pt nanoparticles and atomical dispersed tungsten(W)sites on N-doped carbon nanofibers is developed for CO tolerance HOR catalyst.The presence of W enables the electron transfer from Pt,which promotes electron rearrangement in the Pt-5d orbitals.It not only optimizes the adsorption of H^(*) and CO^(*)on Pt,but also the OH^(*) intermediates adsorbed on the W sites oxidize the CO*adsorbed on Pt,thereby retaining more active sites for H_(2) adsorption and oxidation.The HOR exchange current density of Pt/W@NCNF reaches 1.35 times that of commercial Pt/C,and the limiting current density decreases by only 3.4%after introducing 1000 ppm CO in H_(2).Notably,the Pt/W@NCNF-based PEMFCs deliver markedly superior performance across a range of CO concentrations.The present study demonstrates that electronic modulation of Pt is an effective strategy for simultaneously achieving resistance to CO and promoted HOR activity.
文摘Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.
文摘C1 chemistry is the essence of coal chemistry and natural gas chemistry. Catalytic methods to efficiently convert C1 molecules into fuels and chemicals have been extensively studied. Syngas（CO ＋H_2） conversion is the most important industrial reaction system in C1 chemistry, and Fe and Co catalysts, two major industrial catalysts, have been the focus of fundamental research and industrial application. In the last decade, considerable research efforts have been devoted to discoveries concerning catalyst structure and increasing market demands for olefins and oxygenates. Since the development of efficient catalysts would strongly benefit from catalyst design and the establishment of a new reaction system, this review comprehensively overviews syngas conversion in three main reactions, highlights the advances recently made and the challenges that remain open, and will stimulate future research activities. The first part of the review summarizes the breakthroughs in Fischer-Tropsch synthesis regarding the optimization of activity and stability, determination of the active phase, and mechanistic studies. The second part overviews the modulation of catalytic structure and product selectivity for Fischer-Tropsch to olefins（FTO）. Catalysts designed to produce higher alcohols, as well as to tune product selectivity in C1 chemistry, are described in the third section. Finally, present challenges in syngas conversion are proposed, and the solutions and prospects are discussed from the viewpoint of fundamental research and practical application. This review summarizes the latest advances in the design, preparation, and application of Fe/Co-based catalysts toward syngas conversion and presents the challenges and future directions in producing value-added fuels.
基金support from the Chinese Scholarship Council(201706220080)for W.H.the Natural Science Foundation of Hunan Province(2019JJ50526)for C.P.+1 种基金The Danish Council for Independent Research for the YDUN project(DFF 4093-00297)to J.Z.Villum Experiment(grant No.35844)for X.X.
文摘Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanoparticles(diameter:6±2 nm)are homogeneously immobilized on 2D Ni based MOFs(Ni-BDC,thickness:5±1 nm)to improve the OER stability.Electronic structure modulation for enhanced catalytic activity is studied via adjusting the amount of Fe_(3)O_(4) nanoparticles on Ni-BDC.The optimal Fe_(3)O_(4)/Ni-BDC achieves the best OER performance with an overpotential of 295 mV at 10 mA cm^(-2),a Tafel slope of 47.8 mV dec^(-1) and a considerable catalytic durability of more than 40 h(less than 5 h for Ni-BDC alone).DFT calculations confirm that the active sites for Fe_(3)O_(4)/Ni-BDC are mainly contributed by Fe species with a higher oxidation state,and the potential-determining step(PDS)is the formation of the adsorbed O*species,which are facilitated in the composite.
文摘With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the current issue to focus on consideration. Therefore, this paper will focus on the design method of multi-layer steel structure module and steel frame composite building structure, and analyze and study its structure, so as to improve the utilization rate of steel structure and promote the development of the construction industry.
