The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N‐heterocycles is a challenge.In this study,Ru_(2)P/AC effectively promoted reversible transformations bet...The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N‐heterocycles is a challenge.In this study,Ru_(2)P/AC effectively promoted reversible transformations between unsaturated and saturated N‐heterocycles affording yields of 98%and 99%,respectively.Moreover,a remarkable enhancement in the reusability of Ru_(2)P/AC was observed compared with other Ru‐based catalysts.According to density functional theory calculations,the superior performance of Ru_(2)P/AC was ascribed to specific synergistic factors,namely geometric and electronic effects induced by P.P greatly reduced the large Ru‐Ru ensembles and finely modified the electronic structures,leading to a low reaction barrier and high desorption ability of the catalyst,further boosting the hydrogenation and acceptorless dehydrogenation processes.展开更多
This study investigated the enhancement effects of dissolved carbonates on the peroxymonosulfate-based advanced oxidation process with CuS as a catalyst.It was found that the added CO_(3)^(2−)increased both the cataly...This study investigated the enhancement effects of dissolved carbonates on the peroxymonosulfate-based advanced oxidation process with CuS as a catalyst.It was found that the added CO_(3)^(2−)increased both the catalytic activity and the stability of the catalyst.Under optimized reaction conditions in the presence of CO_(3)^(2−),the degradation removal of 4-methylphenol(4-MP)within 2 min reached 100%,and this was maintained in consecutivemulti-cycle experiments.The degradation rate constant of 4-MP was 2.159 min^(−1),being 685%greater than that in the absence of CO_(3)^(2−)(0.315 min−1).The comparison of dominated active species and 4-MP degradation pathways in both CO_(3)^(2−)-free and CO_(3)^(2−)-containing systems suggested thatmore CO_(3)·^(−)/^(1)O_(2) was produced in the case of CO_(3)^(2−)deducing an electron transfer medium,which tending to react with electron-richmoieties.Meanwhile,Characterization by X-ray photoelectron spectroscopic and cyclic voltammetrymeasurement verified CO_(3)^(2−)enabled the effective reduction of Cu^(2+)to Cu^(+).By investigating the degradation of 11 phenolics with different substituents,the dependence of degradation kinetic rate constant of the phenolics on their chemical structures indicated that there was a good linear relationship between the Hammett constantsσp of the aromatic phenolics and the logarithm of k in the CO_(3)^(2−)-containing system.This work provides a new strategy for efficient removal of electron-rich moieties under the driving of carbonate being widely present in actual water bodies.展开更多
Iron(Fe)-based alloys,which have been widely used as structural materials in nuclear reactors,can significantly change their microstructure properties and macroscopic properties under high flux neutron irradiation dur...Iron(Fe)-based alloys,which have been widely used as structural materials in nuclear reactors,can significantly change their microstructure properties and macroscopic properties under high flux neutron irradiation during operation,thus,the problems associated with the safe operation of nuclear reactors have been put forward naturally.In this work,a molecular dynamics simulation approach combined with electronic effects is developed for investigating the primary radiation damage process inα-Fe.Specifically,the influence of electronic effects on the collision cascade in Fe is systematically evaluated based on two commonly used interatomic potentials for Fe.The simulation results reveal that both electronic stopping(ES)and electron-phonon coupling(EPC)can contribute to the decrease of the number of defects in the thermal spike phase.The application of ES reduces the number of residual defects after the cascade evolution,whereas EPC has a reverse effect.The introduction of electronic effects promotes the formation of the dispersive subcascade:ES significantly changes the geometry of the damaged region in the thermal spike phase,whereas EPC mainly reduces the extent of the damaged region.Furthermore,the incorporation of electronic effects effectively mitigates discrepancies in simulation outcomes when using different interatomic potentials.展开更多
To explore the influence of substituent groups on thermally induced curing,eight new bio-based benzoxazines containing different substituent groups with different electron negativity and volumes were synthesized.The t...To explore the influence of substituent groups on thermally induced curing,eight new bio-based benzoxazines containing different substituent groups with different electron negativity and volumes were synthesized.The thermal curing of these bio-based benzoxazines was studied in detail.Combined with the curing reaction kinetics,simulation and calculation of Highest Occupied Molecular and Lowest Unoccupied Molecular values,the spatial and electronic effects of different substituent groups on the curing of benzoxazine was explored.It was found that when the substituent was located at the position directly connected to the N atom,the steric hindrance effect of the group was dominant.When the substituent group was located on the benzene ring connected to the O atom,both the electronic effect and the spatial effect influenced the curing of benzoxazine.When an electron-withdrawing group was connected ortho position to the O atom,the curing reaction was promoted due to the decreased electron cloud density of O-on the oxazine ring,making the C-O bond easier to break.When an electron-donating group was connected to the meta position of the O atom it also promoted the curing reaction,possibly because it increased the electron cloud density of the+CH2 reaction site and thereby facilitated electrophilic substitution via attack of+CH2 on the cross linking reaction centre.This work provides a deeper understanding of how spatial and electronic effects of substituents affect the curing of benzoxazine.展开更多
Three series of polythiophenes containing fluoroalkoxy and fluoroether substituents were prepared by electrochemical polymerization. The effect of substituents with fluoroalkoxy or ether functional groups on the elect...Three series of polythiophenes containing fluoroalkoxy and fluoroether substituents were prepared by electrochemical polymerization. The effect of substituents with fluoroalkoxy or ether functional groups on the electrochemical polymerization of thiophene monomers and properties of the obtained polymers were analyzed. The introduction of a fluoroether functional group at the 3-position of the thiophene ring leads to an increase of the oxidation potential of the monomer and to a decrease of the conductivity of the resulting polymers, even with the use of a CH2 group as spacer. Conversely, the presence of an oxygen atom directly at the 3-position of the thiophene ring, which offsets the negative withdrawing effect of fluoroalkyl groups, facilitates the synthesis of highly conducting polythiophenes.展开更多
A series of“half-sandwich”bis(imino)pyridyl iron complexes with a substituted 8-(p-Xphenyl)naphthylamine(X=OMe,Me,CF3)was designed and synthesized by combining weakπ-πinteraction with steric and electronic tunings...A series of“half-sandwich”bis(imino)pyridyl iron complexes with a substituted 8-(p-Xphenyl)naphthylamine(X=OMe,Me,CF3)was designed and synthesized by combining weakπ-πinteraction with steric and electronic tunings.The weak noncovalentπ-πinteraction as well as the steric and electronic effects of bis(imino)pyridyl iron complexes were identified by experimental analyses and calculations.The roles of weakπ-πinteraction,steric bulk,and electronic tuning on the ethylene polymerization performance of bis(imino)pyridyl iron catalysts were studied in detail.The combination ofπ-πinteraction with steric and electronic tunings can access to thermally stable bis(imino)pyridyl iron at 130°C.展开更多
GaSb（Bi）/Alo.2Gao.sSb single quantum wells are characterized by a Fourier transform infrared spectrometer- based photoreflectance method at 77K. Spatially direct and indirect transitions between the electronic level...GaSb（Bi）/Alo.2Gao.sSb single quantum wells are characterized by a Fourier transform infrared spectrometer- based photoreflectance method at 77K. Spatially direct and indirect transitions between the electronic levels at and above the effective band gap are well resolved. The shifts of the electronic levels with Bi incorporation are identified quantitatively. The results show that the upshift of the valence band edge is clarified to be dominant, while the Bi-induced downshift of the conduction band edge does exist and contributes to the band gap reduction in the GaSbBi quantum-well layer by （29±6）%.展开更多
Structural, electronic and mechanical properties of the nH-SiC （n = 2, 4, 6, 8 and 10） polytypes are calculated by using the first-principles calculations based on the density-functional theory approach. The optimiz...Structural, electronic and mechanical properties of the nH-SiC （n = 2, 4, 6, 8 and 10） polytypes are calculated by using the first-principles calculations based on the density-functional theory approach. The optimized lattice parameters of nH-SiC are in good agreement with the experimental data. The mechanical properties, including elastic constants, bulk modulus, Young＇s modulus, shear modulus and Poisson＇s ratio, are calculated. The analysis of elastic properties indicates that the effects of n on the mechanical properties of the five nil-SiC structures have no difference. The indirect band gap relationship for the live polytypes is Ebg2H 〉 Ebg4H 〉 Ebg6H 〉 Ebg10H 〉 EbgsH.展开更多
Multi-electron and multi-orbital effects play a crucial role in the interaction of strong laser fields with complex molecules.Here,multi-electron effects encompass not only electron-electron Coulomb interactions and e...Multi-electron and multi-orbital effects play a crucial role in the interaction of strong laser fields with complex molecules.Here,multi-electron effects encompass not only electron-electron Coulomb interactions and exchangecorrelation effects but also the interference between the dynamics of different electron wave packets.展开更多
Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon d...Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon dioxide emissions.However,high hydrogenation energy barrier for*NO intermediates and insufficient supply of active hydrogen cause slow hydrogenation process,and further result in low efficiency of nitrate conversion and ammonia synthesis.Herein,a series of tandem catalysts,one-dimensional coordination polymers(1D CCPs)with dual sites are synthesized and obtained 190.4 mg h^(-1)mgcat^(-1)ammonia production rate with Faradaic efficiency of 97.16%,outperforming to the most of recent reported catalysts.The catalytic performances are well-maintained even after a long-term stability test of 1200 h,laying the foundation for practical applications.Density functional theory results reveal that the stationary adsorbed*NO on Ni site induced proximity electronic effect could reduce the energy barrier for hydrogenation of*NO intermediates over Cu site.In addition,the Ni site in the dual sites 1D CCPs is conducive to generating active hydrogen,providing rich proton source to boost the hydrogenation of*NO,and further enhancing the compatibility of deoxygenation and hydrogenation process.Our work paves a new insight into the mechanism of NITRR process and will inspire more research interests in exploring the proximity electronic effect in catalytic process.展开更多
Platinum-based(Pt)catalysts are notoriously susceptible to deactivation in industrial chemical processes due to carbon monoxide(CO)poisoning.Overcoming this poisoning deactivation of Pt-based catalysts while enhancing...Platinum-based(Pt)catalysts are notoriously susceptible to deactivation in industrial chemical processes due to carbon monoxide(CO)poisoning.Overcoming this poisoning deactivation of Pt-based catalysts while enhancing their catalytic activity,selectivity,and durability remains a major challenge.Herein,we propose a strategy to enhance the CO tolerance of Pt clusters(Pt_n)by introducing neighboring functionalized vip single atoms(such as Fe,Co,Ni,Cu,Sb,and Bi).Among them,antimony(Sb)single atoms(SAs)exhibit significant performance enhancement,achieving 99%CO selectivity and 33.6%CO_(2)conversion at 450℃,Experimental results and density functional theory(DFT)calculations indicate the optimization arises from the electronic interaction between neighboring functionalized Sb SAs and Pt clusters,leading to optimal 5d electron redistribution in Pt clusters compared to other functionalized vip single atoms.The redistribution of 5d electrons weaken both theσdonation andπbackdonation interactions,resulting in a weakened bond strength with CO and enhancing catalyst activity and selectivity.In situ environmental transmission electron microscopy(ETEM)further demonstrates the exception thermal stability of the catalyst,even under H_(2)at 700℃.Notably,the functionalized Sb SAs also improve CO tolerance in various heterogenous catalysts,including Co/CeO_(2),Ni/CeO_(2),Pt/Al_(2)O_(3),and Pt/CeO_(2)-C.This finding provides an effective approach to overcome the primary challenge of CO poisoning in Pt-based catalysts,making their broader applications in various industrial catalysts.展开更多
Developing effective strategy for constructing the electrocatalysts enable tri-functional electrocatalytic activity of hydrogen evolution reaction(HER),oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)i...Developing effective strategy for constructing the electrocatalysts enable tri-functional electrocatalytic activity of hydrogen evolution reaction(HER),oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is the premise to achieve both the zinc-air battery(ZAB)and overall water splitting.Herein,we utilize density functional theory to calculate the cobalt nitride(Co_(x)N,x=1,2,4,5.47)system,revealing that the Co_(5.47)N maybe exhibits a tri-functional activity due to the diverse valence states and high-density d-electron state of Co site.Furthermore,the electron of Co site is further delocalized by the electronic compensation effect of vanadium nitride(VN),thus improving the intermediates absorption and electrocatalytic activity.Accordingly,the Co_(5.47)N/VN heterojunction is designed and synthesized via an electrospinning and a subsequent pyrolysis route.As expected,it displays excellent HER,OER,and ORR activity in alkaline electrolyte,which can be applied to assemble ZAB with a high power density of 207mW/cm^(2)and overall water splitting system only requires a lower voltage of 1.53 V to achieve 10mA/cm^(2).The electron regulation effect of VN makes the Co valence state decrease in the reduction reaction whereas increase in the oxidization reaction as evidenced by quasi-operando XPS analyses.Importantly,two ZABs connected in series could drive overall water splitting,indicating the potential application in renewable energy technologies.展开更多
Aqueous rechargeable Ni-Fe batteries exhibit unique advantages in large-scale energy storage thanks to their affordability,safety,and reliability.However,their limited energy density and Coulombic efficiency stem from...Aqueous rechargeable Ni-Fe batteries exhibit unique advantages in large-scale energy storage thanks to their affordability,safety,and reliability.However,their limited energy density and Coulombic efficiency stem from unfavorable OH^(−)adsorption capability and low electrochemical activity of Fe sites,result in electrode kinetic delays for Fe anodes.Here,we report Mn and S co-modified FeOOH(MSFF)nanosheets as an advanced anode in Ni-Fe batteries,synthesized from a facile one-step surface-redox-etching method at room temperature.Based on the strong electronic coupling effect between Mn and S atoms,such MSFF anode presents fast electron transport capability,enhanced OH^(−)-adsorption capability,and redox reactivity.Specifically,the MSFF anode can achieve a high areal capacity of 2 mAh cm^(−2)at 10 mA cm^(−2),which retains a staggering 96%of the initial capacity after undergoing 9000 cycles at a higher current density of 30 mA cm^(−2).In addition,the assembled Ni-Fe battery can provide a capacity of 0.85 mAh cm^(−2)at 16 mA cm^(−2),significantly outperforming most recently reported aqueous rechargeable batteries.This work may offer an innovative and feasible approach for modulating the local electronic structure of high-performance Ni-Fe battery electrode materials.展开更多
A group of five bis(arylimino)pyridine-cobalt(Ⅱ)chloride complexes,[2-{(2,6-(Ph_(2)CH)_(2)-4-MeOC_(6)H_(2))N=CMe}-6-(ArN=CMe)C_5 H_(3)N]CoCl_(2)(Ar=2,6-Me_(2)C_(6)H_(3)Co1,2,6-Et_(2)C_(6)H_(3)Co2,2,6-iPr_(2)C_(6)H_(3...A group of five bis(arylimino)pyridine-cobalt(Ⅱ)chloride complexes,[2-{(2,6-(Ph_(2)CH)_(2)-4-MeOC_(6)H_(2))N=CMe}-6-(ArN=CMe)C_5 H_(3)N]CoCl_(2)(Ar=2,6-Me_(2)C_(6)H_(3)Co1,2,6-Et_(2)C_(6)H_(3)Co2,2,6-iPr_(2)C_(6)H_(3)Co3,2,4,6-Me_(3)C_(6)H_(2)Co4,2,6-Et_(2)-4-MeC_(6)H_(2)Co5),each containing one N-4-methoxy-2,6-dibenzhydrylphenyl group and one smaller sterically/electronically variable N-aryl group,have been synthesized in good yield(>71%)from the corresponding neutral terdentate nitrogen-donor precursor,L1-L5.All complexes have been characterized by^(1)H-NMR and FTIR spectroscopy with the former highlighting the paramagnetic nature of these cobaltous species and the unsymmetrical nature of the chelating ligand.The molecular structures of Co3 and Co4 emphasize the steric differences of the two inequivalent N-aryl groups and the distorted square pyramidal geometry about the metal centers.In the presence of MAO or MMAO,Co1-Co5 collectively displayed high activities for ethylene polymerization producing high molecular weight polyethylenes that,in general,exhibited narrow dispersities(M_w/M_n values:2.12-4.07).Notably,the least sterically hindered Co1 when activated with MAO was the most productive(6.92×10^(6)g_(PE)·mol^(-1)_((Co))·h^(-1))at an operating temperature of60℃.Conversely,the most sterically hindered Co3/MMAO produced the highest molecular weight polyethylene(M_w=6.29×10^(5)g·mol^(-1)).All the polymers displayed high linearity as demonstrated by their melting temperatures(>130℃)and their~1 H-and^(13)C-NMR spectra.By comparison of Co1 with its para-methyl,-chloro and-nitro counterparts,the presence of the para-methoxy substituent showed the most noticeable effect of enhancing the thermal stability of the catalyst.展开更多
In this study,the support effects on the Pd-catalyzed semi-hydrogenation of acetylene have been investigated from the structural and kinetic perspectives.According to the results of kinetic analysis and X-ray photoele...In this study,the support effects on the Pd-catalyzed semi-hydrogenation of acetylene have been investigated from the structural and kinetic perspectives.According to the results of kinetic analysis and X-ray photoelectron spectroscopy,hydrogen temperature-programmed reduction,temperature-programmed hydride decomposition,and in situ X-ray diffraction measurements,using carbon nanotubes as support for Pd nanocatalysts with various sizes instead of a-Al_(2)O_(3) decreases the Pd^(0)3d binding energy and suppresses the formation of undesirable palladium hydride species,thus increasing the ethylene yield.Furthermore,X-ray absorption spectroscopy,high-resolution transmission electron microscopy,and C_(2)H_(4) temperature-programmed desorption studies combined with density-functional theory calculations reveal the existence of a unique Pd local environment,containing subsurface carbon atoms,that produces positive geometric effects on the acetylene conversion reaction.Therefore,tailoring the Pd local environment and electronic properties represents an effective strategy for the fabrication and design of highly active and selective Pd semi-hydrogenation catalysts.展开更多
Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materia...Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materials to obtain satisfactory performance at low-to-moderate overpotentials.Herein,a simple and facile electrospinning technique is utilized to prepare a composite of a bimetallic Sn-Co oxide/carbon matrix with a hollow nanotube structure(Sn Co-HNT).Sn Co-HNT can maintain>90%faradaic efficiencies for C1 products within a wide potential range from-0.6 VRHE to-1.2 VRHE,and a highest 94.1%selectivity towards CO in an H-type cell.Moreover,a 91.2%faradaic efficiency with a 241.3 m A cm^(-2)partial current density for C1 products could be achieved using a flow cell.According to theoretical calculations,the fusing of Sn/Co oxides on the carbon matrix accelerates electron transfer at the atomic level,causing electron deficiency of Sn centers and reversible variation between Co^(2+)and Co^(3+)centers.The synergistic effect of the Sn/Co composition improves the electron affinity of the catalyst surface,which is conducive to the adsorption and stabilization of key intermediates and eventually increases the catalytic activity in CO_(2)electroreduction.This study could provide a new strategy for the construction of oxide-derived catalysts for CO_(2)electroreduction.展开更多
Direct ethanol fuel cell is a promising low temperature fuel cell,but its development is hindered by sluggish kinetics of anode catalysts for ethanol oxidation.Here a high efficient platinum/tin oxide/Graphene nanocom...Direct ethanol fuel cell is a promising low temperature fuel cell,but its development is hindered by sluggish kinetics of anode catalysts for ethanol oxidation.Here a high efficient platinum/tin oxide/Graphene nanocomposite is synthesized through a facile and environmentally benign method.The structure and morphology are carefully characterized by X-ray diffraction and Transmission electron microscopy,showing a clear platinum/tin oxide heterostructure uniformly dispersed on graphene support.This catalyst demonstrates the highest activity among the reported catalysts and much higher durability towards ethanol oxidation compared to conventional platinum nanocatalysts.The ultrahigh activity originates from promoted removal of poisoning carbon monoxide immediate species on platinum due to a strong electronic donating effect from both tin oxide and graphene,which is fully supported by carbon monoxide stripping and X-ray photoelectron spectroscopy analysis.Our platinum/tin oxide/Graphene appears to be a promising candidate for ethanol oxidation electrocatalysts.展开更多
The objective of this work is to contribute an understanding of the effects of electrons in the plasmas on the mass transfer of plasma species in aqueous solution by means of the numerical simulation based on a one-di...The objective of this work is to contribute an understanding of the effects of electrons in the plasmas on the mass transfer of plasma species in aqueous solution by means of the numerical simulation based on a one-dimensional diffusion-reaction model.The plasma species are divided into two groups,i.e.electrons and the other species,and the mass transfer in the three scenarios has been simulated,including the systematic calculations of the depth distributions of five major reactive species,OH,O3,HO2,O2^-,and H2O2.In the three scenarios,the particles considered to enter into aqueous solution are all the plasma species(the scenario Ⅰ,where the mass transfer of plasma species is a result due to the synergy of the electrons and the other plasma species),the other species(the scenario Ⅱ),and only electrons in plasma species(the scenario Ⅲ),respectively.The detailed analyses on the difference between the depth distributions of each reactive species in these three scenarios show the following conclusions.The electrons play an important role in the mass transfer of plasma species in aqueous solution and the synergy of the electrons and the other plasma species(the electron-species synergy)presents its different effects on the mass transfer.The vast majority of H2O2 are generated from a series of the electronrelated reactions in aqueous solution,which is hardly affected by the electron-species synergy.Compared to the results when only the electrons enter into the liquid region,the electron-species synergy evidently weakens the generation of O2^-,O3,and OH,but promotes to produce HO2.展开更多
In order to improve the catalytic performance of the nitrobenzene hydrogenation rearrangement to prepare p-aminophenol,a bimetallic Pt-Ni/C(PNC)catalyst was synthesized.Taking advantage of the synergistic effect of Ni...In order to improve the catalytic performance of the nitrobenzene hydrogenation rearrangement to prepare p-aminophenol,a bimetallic Pt-Ni/C(PNC)catalyst was synthesized.Taking advantage of the synergistic effect of Ni and Pt to enhance product selectivity and catalytic performance stability,the electrons in Ni are moved to Pt by the electron effect,which affects the catalyst’s ability to activate H_(2)as well as the amount of hydrogen activated.Furthermore,due to the strong Pt(5d)-Ni(3d)coupling effect,Ni can effectively maintain Pt stability in the acidic system and reduce Pt dissolution.The stability of the PNC can be found to be greatly enhanced compared to the Pt/C(PC)catalyst,and p-aminophenol selectivity is greatly enhanced,showing excellent catalytic performance.展开更多
A first-order itinerant electron metamagnetic (IEM) transition above the Curie temperature Tc for ferromagnetic La(Fe_xSi_1-x)13 compounds has been confirmed by applying magnetic field. The volume change just above T_...A first-order itinerant electron metamagnetic (IEM) transition above the Curie temperature Tc for ferromagnetic La(Fe_xSi_1-x)13 compounds has been confirmed by applying magnetic field. The volume change just above T_C for x=0.88 is huge of about 1.5%, which is caused by a large magnetic moment induced by the IEM transition. These compounds have a possibility for practical applications as giant magnetostrictive materials. Pronounced Invar effects bring about a negative thermal expansion below TC, closely correlated with the negative mode-mode coupling among spin fluctuations.展开更多
文摘The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N‐heterocycles is a challenge.In this study,Ru_(2)P/AC effectively promoted reversible transformations between unsaturated and saturated N‐heterocycles affording yields of 98%and 99%,respectively.Moreover,a remarkable enhancement in the reusability of Ru_(2)P/AC was observed compared with other Ru‐based catalysts.According to density functional theory calculations,the superior performance of Ru_(2)P/AC was ascribed to specific synergistic factors,namely geometric and electronic effects induced by P.P greatly reduced the large Ru‐Ru ensembles and finely modified the electronic structures,leading to a low reaction barrier and high desorption ability of the catalyst,further boosting the hydrogenation and acceptorless dehydrogenation processes.
基金This work was supported by the National Science Foundation of Hubei Province of China(No.2019CFB432)the National Natural Science Foundation of China(Nos.22076052 and 21976063)the China Postdoctoral Science Foundation(No.2018M642850).
文摘This study investigated the enhancement effects of dissolved carbonates on the peroxymonosulfate-based advanced oxidation process with CuS as a catalyst.It was found that the added CO_(3)^(2−)increased both the catalytic activity and the stability of the catalyst.Under optimized reaction conditions in the presence of CO_(3)^(2−),the degradation removal of 4-methylphenol(4-MP)within 2 min reached 100%,and this was maintained in consecutivemulti-cycle experiments.The degradation rate constant of 4-MP was 2.159 min^(−1),being 685%greater than that in the absence of CO_(3)^(2−)(0.315 min−1).The comparison of dominated active species and 4-MP degradation pathways in both CO_(3)^(2−)-free and CO_(3)^(2−)-containing systems suggested thatmore CO_(3)·^(−)/^(1)O_(2) was produced in the case of CO_(3)^(2−)deducing an electron transfer medium,which tending to react with electron-richmoieties.Meanwhile,Characterization by X-ray photoelectron spectroscopic and cyclic voltammetrymeasurement verified CO_(3)^(2−)enabled the effective reduction of Cu^(2+)to Cu^(+).By investigating the degradation of 11 phenolics with different substituents,the dependence of degradation kinetic rate constant of the phenolics on their chemical structures indicated that there was a good linear relationship between the Hammett constantsσp of the aromatic phenolics and the logarithm of k in the CO_(3)^(2−)-containing system.This work provides a new strategy for efficient removal of electron-rich moieties under the driving of carbonate being widely present in actual water bodies.
基金Project supported by the National MCF Energy Research and Development Program of China(Grant Nos.2022YFE03200200 and 2018YFE0308101)the National Natural Science Foundation of China(Grant No.12105194)the Natural Science Foundation of Sichuan Province,China(Grant Nos.2022NSFSC1265 and 2022NSFSC1251).
文摘Iron(Fe)-based alloys,which have been widely used as structural materials in nuclear reactors,can significantly change their microstructure properties and macroscopic properties under high flux neutron irradiation during operation,thus,the problems associated with the safe operation of nuclear reactors have been put forward naturally.In this work,a molecular dynamics simulation approach combined with electronic effects is developed for investigating the primary radiation damage process inα-Fe.Specifically,the influence of electronic effects on the collision cascade in Fe is systematically evaluated based on two commonly used interatomic potentials for Fe.The simulation results reveal that both electronic stopping(ES)and electron-phonon coupling(EPC)can contribute to the decrease of the number of defects in the thermal spike phase.The application of ES reduces the number of residual defects after the cascade evolution,whereas EPC has a reverse effect.The introduction of electronic effects promotes the formation of the dispersive subcascade:ES significantly changes the geometry of the damaged region in the thermal spike phase,whereas EPC mainly reduces the extent of the damaged region.Furthermore,the incorporation of electronic effects effectively mitigates discrepancies in simulation outcomes when using different interatomic potentials.
基金This work was partially supported by the National Natural Science Foundation of China(51773060,and 52073091)Shanghai Natural Science Foundation(20ZR1414600)+1 种基金Shanghai Aerospace Science and Technology Innovation Fund(SAST2020-087)the Fundamental Research Funds for the Central Universities(50321042017001).
文摘To explore the influence of substituent groups on thermally induced curing,eight new bio-based benzoxazines containing different substituent groups with different electron negativity and volumes were synthesized.The thermal curing of these bio-based benzoxazines was studied in detail.Combined with the curing reaction kinetics,simulation and calculation of Highest Occupied Molecular and Lowest Unoccupied Molecular values,the spatial and electronic effects of different substituent groups on the curing of benzoxazine was explored.It was found that when the substituent was located at the position directly connected to the N atom,the steric hindrance effect of the group was dominant.When the substituent group was located on the benzene ring connected to the O atom,both the electronic effect and the spatial effect influenced the curing of benzoxazine.When an electron-withdrawing group was connected ortho position to the O atom,the curing reaction was promoted due to the decreased electron cloud density of O-on the oxazine ring,making the C-O bond easier to break.When an electron-donating group was connected to the meta position of the O atom it also promoted the curing reaction,possibly because it increased the electron cloud density of the+CH2 reaction site and thereby facilitated electrophilic substitution via attack of+CH2 on the cross linking reaction centre.This work provides a deeper understanding of how spatial and electronic effects of substituents affect the curing of benzoxazine.
基金This work was supported by the National Natural Science Foundation of China.
文摘Three series of polythiophenes containing fluoroalkoxy and fluoroether substituents were prepared by electrochemical polymerization. The effect of substituents with fluoroalkoxy or ether functional groups on the electrochemical polymerization of thiophene monomers and properties of the obtained polymers were analyzed. The introduction of a fluoroether functional group at the 3-position of the thiophene ring leads to an increase of the oxidation potential of the monomer and to a decrease of the conductivity of the resulting polymers, even with the use of a CH2 group as spacer. Conversely, the presence of an oxygen atom directly at the 3-position of the thiophene ring, which offsets the negative withdrawing effect of fluoroalkyl groups, facilitates the synthesis of highly conducting polythiophenes.
基金supported by the State Key Research Development Program of China(No.2021YFB3800701)National Natural Science Foundation of China(NSFC,No.52173016)+2 种基金Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515012784,2024A1515011102,and 2023A1515110549)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.24qnpy047)PetroChina Scientific and Technological Projects(No.2022DJ6308).
文摘A series of“half-sandwich”bis(imino)pyridyl iron complexes with a substituted 8-(p-Xphenyl)naphthylamine(X=OMe,Me,CF3)was designed and synthesized by combining weakπ-πinteraction with steric and electronic tunings.The weak noncovalentπ-πinteraction as well as the steric and electronic effects of bis(imino)pyridyl iron complexes were identified by experimental analyses and calculations.The roles of weakπ-πinteraction,steric bulk,and electronic tuning on the ethylene polymerization performance of bis(imino)pyridyl iron catalysts were studied in detail.The combination ofπ-πinteraction with steric and electronic tunings can access to thermally stable bis(imino)pyridyl iron at 130°C.
基金Supported by the National Basic Research Program of China under Grant No 2014CB643901the National Natural Science Foundation of China under Grant Nos 11274329 and 61321492the Key Research Program of the Chinese Academy of Sciences under Grant Nos XDA5-1 and KGZD-EW-804
文摘GaSb（Bi）/Alo.2Gao.sSb single quantum wells are characterized by a Fourier transform infrared spectrometer- based photoreflectance method at 77K. Spatially direct and indirect transitions between the electronic levels at and above the effective band gap are well resolved. The shifts of the electronic levels with Bi incorporation are identified quantitatively. The results show that the upshift of the valence band edge is clarified to be dominant, while the Bi-induced downshift of the conduction band edge does exist and contributes to the band gap reduction in the GaSbBi quantum-well layer by （29±6）%.
基金Supported by the National Natural Science Foundation of China under Grant No 51372203the National Basic Research Program of China under Grant No 2011CB605806+1 种基金the Basic Research Foundation of Northwestern Polytechnical University under Grant Nos JCY20130114 and JCY20110248the Foreign Talents Introduction and Academic Exchange Program under Grant No B08040
文摘Structural, electronic and mechanical properties of the nH-SiC （n = 2, 4, 6, 8 and 10） polytypes are calculated by using the first-principles calculations based on the density-functional theory approach. The optimized lattice parameters of nH-SiC are in good agreement with the experimental data. The mechanical properties, including elastic constants, bulk modulus, Young＇s modulus, shear modulus and Poisson＇s ratio, are calculated. The analysis of elastic properties indicates that the effects of n on the mechanical properties of the five nil-SiC structures have no difference. The indirect band gap relationship for the live polytypes is Ebg2H 〉 Ebg4H 〉 Ebg6H 〉 Ebg10H 〉 EbgsH.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0134200)the National Natural Science Foundation of China(Grant No.12204214)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.GK202207012)QCYRCXM-2022-241。
文摘Multi-electron and multi-orbital effects play a crucial role in the interaction of strong laser fields with complex molecules.Here,multi-electron effects encompass not only electron-electron Coulomb interactions and exchangecorrelation effects but also the interference between the dynamics of different electron wave packets.
文摘Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon dioxide emissions.However,high hydrogenation energy barrier for*NO intermediates and insufficient supply of active hydrogen cause slow hydrogenation process,and further result in low efficiency of nitrate conversion and ammonia synthesis.Herein,a series of tandem catalysts,one-dimensional coordination polymers(1D CCPs)with dual sites are synthesized and obtained 190.4 mg h^(-1)mgcat^(-1)ammonia production rate with Faradaic efficiency of 97.16%,outperforming to the most of recent reported catalysts.The catalytic performances are well-maintained even after a long-term stability test of 1200 h,laying the foundation for practical applications.Density functional theory results reveal that the stationary adsorbed*NO on Ni site induced proximity electronic effect could reduce the energy barrier for hydrogenation of*NO intermediates over Cu site.In addition,the Ni site in the dual sites 1D CCPs is conducive to generating active hydrogen,providing rich proton source to boost the hydrogenation of*NO,and further enhancing the compatibility of deoxygenation and hydrogenation process.Our work paves a new insight into the mechanism of NITRR process and will inspire more research interests in exploring the proximity electronic effect in catalytic process.
基金financially supported by the Shanghai RisingStar Program(No.23QA1403700)the National Natural Science Foundation of China(NSFC,Grant No.U2230102)+1 种基金the sponsored by National Key Research and Development Program of China(No.2021YFB3502200)the Shanghai Technical Service Center of Science and Engineering Computing,Shanghai University.
文摘Platinum-based(Pt)catalysts are notoriously susceptible to deactivation in industrial chemical processes due to carbon monoxide(CO)poisoning.Overcoming this poisoning deactivation of Pt-based catalysts while enhancing their catalytic activity,selectivity,and durability remains a major challenge.Herein,we propose a strategy to enhance the CO tolerance of Pt clusters(Pt_n)by introducing neighboring functionalized vip single atoms(such as Fe,Co,Ni,Cu,Sb,and Bi).Among them,antimony(Sb)single atoms(SAs)exhibit significant performance enhancement,achieving 99%CO selectivity and 33.6%CO_(2)conversion at 450℃,Experimental results and density functional theory(DFT)calculations indicate the optimization arises from the electronic interaction between neighboring functionalized Sb SAs and Pt clusters,leading to optimal 5d electron redistribution in Pt clusters compared to other functionalized vip single atoms.The redistribution of 5d electrons weaken both theσdonation andπbackdonation interactions,resulting in a weakened bond strength with CO and enhancing catalyst activity and selectivity.In situ environmental transmission electron microscopy(ETEM)further demonstrates the exception thermal stability of the catalyst,even under H_(2)at 700℃.Notably,the functionalized Sb SAs also improve CO tolerance in various heterogenous catalysts,including Co/CeO_(2),Ni/CeO_(2),Pt/Al_(2)O_(3),and Pt/CeO_(2)-C.This finding provides an effective approach to overcome the primary challenge of CO poisoning in Pt-based catalysts,making their broader applications in various industrial catalysts.
基金the National Key R&D Program of China(No.2023YFA1507204)the National Natural Science Foundation of China(Nos.U20A20250,22279030,22179034)the Natural Science Foundation of Heilongjiang Province(No.ZD2023B002).
文摘Developing effective strategy for constructing the electrocatalysts enable tri-functional electrocatalytic activity of hydrogen evolution reaction(HER),oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is the premise to achieve both the zinc-air battery(ZAB)and overall water splitting.Herein,we utilize density functional theory to calculate the cobalt nitride(Co_(x)N,x=1,2,4,5.47)system,revealing that the Co_(5.47)N maybe exhibits a tri-functional activity due to the diverse valence states and high-density d-electron state of Co site.Furthermore,the electron of Co site is further delocalized by the electronic compensation effect of vanadium nitride(VN),thus improving the intermediates absorption and electrocatalytic activity.Accordingly,the Co_(5.47)N/VN heterojunction is designed and synthesized via an electrospinning and a subsequent pyrolysis route.As expected,it displays excellent HER,OER,and ORR activity in alkaline electrolyte,which can be applied to assemble ZAB with a high power density of 207mW/cm^(2)and overall water splitting system only requires a lower voltage of 1.53 V to achieve 10mA/cm^(2).The electron regulation effect of VN makes the Co valence state decrease in the reduction reaction whereas increase in the oxidization reaction as evidenced by quasi-operando XPS analyses.Importantly,two ZABs connected in series could drive overall water splitting,indicating the potential application in renewable energy technologies.
基金financially supported by National Natural Science Foundation of China(Nos.52407242,52162025)Specific Research Fund of the Innovation Platform for Academicians of Hainan Province(No.YSPTZX202123).
文摘Aqueous rechargeable Ni-Fe batteries exhibit unique advantages in large-scale energy storage thanks to their affordability,safety,and reliability.However,their limited energy density and Coulombic efficiency stem from unfavorable OH^(−)adsorption capability and low electrochemical activity of Fe sites,result in electrode kinetic delays for Fe anodes.Here,we report Mn and S co-modified FeOOH(MSFF)nanosheets as an advanced anode in Ni-Fe batteries,synthesized from a facile one-step surface-redox-etching method at room temperature.Based on the strong electronic coupling effect between Mn and S atoms,such MSFF anode presents fast electron transport capability,enhanced OH^(−)-adsorption capability,and redox reactivity.Specifically,the MSFF anode can achieve a high areal capacity of 2 mAh cm^(−2)at 10 mA cm^(−2),which retains a staggering 96%of the initial capacity after undergoing 9000 cycles at a higher current density of 30 mA cm^(−2).In addition,the assembled Ni-Fe battery can provide a capacity of 0.85 mAh cm^(−2)at 16 mA cm^(−2),significantly outperforming most recently reported aqueous rechargeable batteries.This work may offer an innovative and feasible approach for modulating the local electronic structure of high-performance Ni-Fe battery electrode materials.
基金financially supported by the National Natural Science Foundation of China(No.21871275)。
文摘A group of five bis(arylimino)pyridine-cobalt(Ⅱ)chloride complexes,[2-{(2,6-(Ph_(2)CH)_(2)-4-MeOC_(6)H_(2))N=CMe}-6-(ArN=CMe)C_5 H_(3)N]CoCl_(2)(Ar=2,6-Me_(2)C_(6)H_(3)Co1,2,6-Et_(2)C_(6)H_(3)Co2,2,6-iPr_(2)C_(6)H_(3)Co3,2,4,6-Me_(3)C_(6)H_(2)Co4,2,6-Et_(2)-4-MeC_(6)H_(2)Co5),each containing one N-4-methoxy-2,6-dibenzhydrylphenyl group and one smaller sterically/electronically variable N-aryl group,have been synthesized in good yield(>71%)from the corresponding neutral terdentate nitrogen-donor precursor,L1-L5.All complexes have been characterized by^(1)H-NMR and FTIR spectroscopy with the former highlighting the paramagnetic nature of these cobaltous species and the unsymmetrical nature of the chelating ligand.The molecular structures of Co3 and Co4 emphasize the steric differences of the two inequivalent N-aryl groups and the distorted square pyramidal geometry about the metal centers.In the presence of MAO or MMAO,Co1-Co5 collectively displayed high activities for ethylene polymerization producing high molecular weight polyethylenes that,in general,exhibited narrow dispersities(M_w/M_n values:2.12-4.07).Notably,the least sterically hindered Co1 when activated with MAO was the most productive(6.92×10^(6)g_(PE)·mol^(-1)_((Co))·h^(-1))at an operating temperature of60℃.Conversely,the most sterically hindered Co3/MMAO produced the highest molecular weight polyethylene(M_w=6.29×10^(5)g·mol^(-1)).All the polymers displayed high linearity as demonstrated by their melting temperatures(>130℃)and their~1 H-and^(13)C-NMR spectra.By comparison of Co1 with its para-methyl,-chloro and-nitro counterparts,the presence of the para-methoxy substituent showed the most noticeable effect of enhancing the thermal stability of the catalyst.
基金This work was financially supported by the Natural Science Foundation of China(21922803,21776077,and 22008067)the Innovation Program of Shanghai Municipal Education Commission,the Shanghai Natural Science Foundation(17ZR1407300 and 17ZR1407500)+4 种基金the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning,the Shanghai Rising-Star Program(17QA1401200)the China Postdoctoral Science Foundation(2020M681202)the Open Project of State Key Laboratory of Chemical Engineering(SKLChe-15C03)the State Key Laboratory of Organic-Inorganic Composites(oic-201801007)the Fundamental Research Funds for the Central Universities(222201718003).
文摘In this study,the support effects on the Pd-catalyzed semi-hydrogenation of acetylene have been investigated from the structural and kinetic perspectives.According to the results of kinetic analysis and X-ray photoelectron spectroscopy,hydrogen temperature-programmed reduction,temperature-programmed hydride decomposition,and in situ X-ray diffraction measurements,using carbon nanotubes as support for Pd nanocatalysts with various sizes instead of a-Al_(2)O_(3) decreases the Pd^(0)3d binding energy and suppresses the formation of undesirable palladium hydride species,thus increasing the ethylene yield.Furthermore,X-ray absorption spectroscopy,high-resolution transmission electron microscopy,and C_(2)H_(4) temperature-programmed desorption studies combined with density-functional theory calculations reveal the existence of a unique Pd local environment,containing subsurface carbon atoms,that produces positive geometric effects on the acetylene conversion reaction.Therefore,tailoring the Pd local environment and electronic properties represents an effective strategy for the fabrication and design of highly active and selective Pd semi-hydrogenation catalysts.
基金supported by the National Natural Science Foundation of China(U21A20312,22172099,21975162,51902209)the Natural Science Foundation of Guangdong(2020A1515010840)the Shenzhen Science and Technology Program(SGDX20201103095802006,RCBS20200714114819161,JCYJ20190808111801674,JCYJ20200109105803806,RCYX20200714114535052)。
文摘Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materials to obtain satisfactory performance at low-to-moderate overpotentials.Herein,a simple and facile electrospinning technique is utilized to prepare a composite of a bimetallic Sn-Co oxide/carbon matrix with a hollow nanotube structure(Sn Co-HNT).Sn Co-HNT can maintain>90%faradaic efficiencies for C1 products within a wide potential range from-0.6 VRHE to-1.2 VRHE,and a highest 94.1%selectivity towards CO in an H-type cell.Moreover,a 91.2%faradaic efficiency with a 241.3 m A cm^(-2)partial current density for C1 products could be achieved using a flow cell.According to theoretical calculations,the fusing of Sn/Co oxides on the carbon matrix accelerates electron transfer at the atomic level,causing electron deficiency of Sn centers and reversible variation between Co^(2+)and Co^(3+)centers.The synergistic effect of the Sn/Co composition improves the electron affinity of the catalyst surface,which is conducive to the adsorption and stabilization of key intermediates and eventually increases the catalytic activity in CO_(2)electroreduction.This study could provide a new strategy for the construction of oxide-derived catalysts for CO_(2)electroreduction.
基金grateful to the financial support from the Key Research and Development Project of Tianjin(18ZXJMTG00180)the National Nature Science Foundation of China(21433003)~~
文摘Direct ethanol fuel cell is a promising low temperature fuel cell,but its development is hindered by sluggish kinetics of anode catalysts for ethanol oxidation.Here a high efficient platinum/tin oxide/Graphene nanocomposite is synthesized through a facile and environmentally benign method.The structure and morphology are carefully characterized by X-ray diffraction and Transmission electron microscopy,showing a clear platinum/tin oxide heterostructure uniformly dispersed on graphene support.This catalyst demonstrates the highest activity among the reported catalysts and much higher durability towards ethanol oxidation compared to conventional platinum nanocatalysts.The ultrahigh activity originates from promoted removal of poisoning carbon monoxide immediate species on platinum due to a strong electronic donating effect from both tin oxide and graphene,which is fully supported by carbon monoxide stripping and X-ray photoelectron spectroscopy analysis.Our platinum/tin oxide/Graphene appears to be a promising candidate for ethanol oxidation electrocatalysts.
基金supported by the Fundamental Research Funds of Shandong University(2018TB037)。
文摘The objective of this work is to contribute an understanding of the effects of electrons in the plasmas on the mass transfer of plasma species in aqueous solution by means of the numerical simulation based on a one-dimensional diffusion-reaction model.The plasma species are divided into two groups,i.e.electrons and the other species,and the mass transfer in the three scenarios has been simulated,including the systematic calculations of the depth distributions of five major reactive species,OH,O3,HO2,O2^-,and H2O2.In the three scenarios,the particles considered to enter into aqueous solution are all the plasma species(the scenario Ⅰ,where the mass transfer of plasma species is a result due to the synergy of the electrons and the other plasma species),the other species(the scenario Ⅱ),and only electrons in plasma species(the scenario Ⅲ),respectively.The detailed analyses on the difference between the depth distributions of each reactive species in these three scenarios show the following conclusions.The electrons play an important role in the mass transfer of plasma species in aqueous solution and the synergy of the electrons and the other plasma species(the electron-species synergy)presents its different effects on the mass transfer.The vast majority of H2O2 are generated from a series of the electronrelated reactions in aqueous solution,which is hardly affected by the electron-species synergy.Compared to the results when only the electrons enter into the liquid region,the electron-species synergy evidently weakens the generation of O2^-,O3,and OH,but promotes to produce HO2.
基金funded by the National Natural Science Foundation of China(U20A20119,22078292 and 22008212)。
文摘In order to improve the catalytic performance of the nitrobenzene hydrogenation rearrangement to prepare p-aminophenol,a bimetallic Pt-Ni/C(PNC)catalyst was synthesized.Taking advantage of the synergistic effect of Ni and Pt to enhance product selectivity and catalytic performance stability,the electrons in Ni are moved to Pt by the electron effect,which affects the catalyst’s ability to activate H_(2)as well as the amount of hydrogen activated.Furthermore,due to the strong Pt(5d)-Ni(3d)coupling effect,Ni can effectively maintain Pt stability in the acidic system and reduce Pt dissolution.The stability of the PNC can be found to be greatly enhanced compared to the Pt/C(PC)catalyst,and p-aminophenol selectivity is greatly enhanced,showing excellent catalytic performance.
基金Japanese Ministry of Education, Science, Sports and Culture!Grantin-Aid for Scientific Research (B)(2) 08455287
文摘A first-order itinerant electron metamagnetic (IEM) transition above the Curie temperature Tc for ferromagnetic La(Fe_xSi_1-x)13 compounds has been confirmed by applying magnetic field. The volume change just above T_C for x=0.88 is huge of about 1.5%, which is caused by a large magnetic moment induced by the IEM transition. These compounds have a possibility for practical applications as giant magnetostrictive materials. Pronounced Invar effects bring about a negative thermal expansion below TC, closely correlated with the negative mode-mode coupling among spin fluctuations.
