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
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
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
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
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
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
Graphite intercalation compounds（GIC） were tested as an experimental model for studying the electronic effect of carbon support on the catalytic activity and poisoning tolerance of Pt catalyst for direct methanol fu...Graphite intercalation compounds（GIC） were tested as an experimental model for studying the electronic effect of carbon support on the catalytic activity and poisoning tolerance of Pt catalyst for direct methanol fuel cells. The GIC samples with different intercalation degrees were prepared by electrolyzing graphite flake in H2SO4 for varying the periods of time. The GIC-supported Pt catalyst was deposited electrochemically. The catalytic activity and poisoning tolerance of the GIC-supported Pt catalysts were evaluated. It was found that GIC with sulfate anion as intercalate was able to catalyze methanol electrooxidation, which could be related to the positive charges generated on the graphite layer upon intercalation. As intercalation degree increased, the catalytic activity of the GIC-supported Pt catalyst decreased while the poisoning tolerance improved. This suggests that electron donation from support to catalyst had great effect on both catalytic activity and poisoning tolerance of Pt catalyst. And intercalation can be adopted as another important way to make modification on carboneous catalyst support.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
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
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
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
Structural regulation of Pd-based electrocatalytic hydrodechlorination(EHDC)catalyst for constructing high-efficient cathode materials with low noble metal content and high atom utilization is crucial but still challe...Structural regulation of Pd-based electrocatalytic hydrodechlorination(EHDC)catalyst for constructing high-efficient cathode materials with low noble metal content and high atom utilization is crucial but still challenging.Herein,a support electron inductive effect of Pd-Mn/Ni foam catalyst was proposed via in-situ Mn doping to optimize the electronic structure of the Ni foam(NF),which can inductive regulation of Pd for improving the EHDC performance.The mass activity and current efficiency of Pd-Mn/NF catalyst are 2.91 and 1.34 times superior to that of Pd/NF with 2,4-dichlorophenol as model compound,respectively.The Mn-doped interlayer optimized the electronic structure of Pd by bringing the d-state closer to the Fermi level than Pd on the NF surface,which optimizied the binding of EHDC intermediates.Additionally,the Mn-doped interlayer acted as a promoter for generating H∗and accelerating the EHDC reaction.This work presents a simple and effective regulation strategy for constructing high-efficient cathode catalyst for the EHDC of chlorinated organic compounds.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
Two novel AIE-active salicylaldehyde azine(SAA) derivatives with a typical excited-state intramolecular proton transfer(ESIPT) process are prepared by introducing electron-withdrawing and donating groups at para-posit...Two novel AIE-active salicylaldehyde azine(SAA) derivatives with a typical excited-state intramolecular proton transfer(ESIPT) process are prepared by introducing electron-withdrawing and donating groups at para-position of phenolic hydroxyl group(CN-SAA and TPA-SAA). The effect of the proton activity in SAA framework on their optical behaviors is investigated spectroscopically. The results from NMR and solvation measurements show that the proton of phenolic hydroxyl group has higher activity when there are electron-withdrawing groups, and the absorption and fluorescence spectra in buffers with different pH also provide the same results. After inviting F. as a nucleophilic probe, this proton activity difference in CN-SAA and TPA-SAA becomes more obvious. The potential application of both molecules is investigated. TPA-SAA exhibits good quantitative sensing ability towards F. with a fluorescence "turn-on" mode, whereas the aggregates of TPA-SAA can selectively and sensitively detect Cu2+ in aqueous solution. From these results, a structure-property relationship is established: the occurrence of ESIPT process will become much easier when linking electron-withdrawing groups at the para-position of phenolic hydroxyl group(e.g., CN-SAA),and it is better to introduce electron-donating groups to enhance the sensing ability towards ions(e.g., TPA-SAA). This work will provide guidance for further design and preparation of AIE-active luminogens with ESIPT process for sensing applications.展开更多
The adjustable intermediate binding capacity in electrocatalytic carbon dioxide(CO_(2))reduction is critical for varying the reaction pathways to desired products.Herein,we first report the synthesis of boron-doped am...The adjustable intermediate binding capacity in electrocatalytic carbon dioxide(CO_(2))reduction is critical for varying the reaction pathways to desired products.Herein,we first report the synthesis of boron-doped amorphous zinc oxide with(B-a-ZnO-Sb)or without antimony nanoparticles embedding(B-a-ZnO)via one-step wet chemical method,which is easy to scale up by enlarging the vessel and increasing feeding.Sb successfully realizes the product switching from CO on B-a-ZnO to formate on B-a-ZnOSb.Both experimental and theoretical results reveal that Sb weakens the charge interaction on Zn atoms.Based on the moderate adsorption of*COOH and strong adsorption of*OCHO and*HCOOH for B-a-ZnO,the foreign Sb weakens the adsorption of these intermediates and brings about a favor formate production instead of CO.This work points out a new direction for the synthesis of amorphous ZnO-based catalysts and provides advanced insights into the aimed selectivity switch for CO_(2)reduction by electronic effect.展开更多
The seminal report ofα-diimine palladium and nickel catalysts in 1995 represented a major breakthrough in the preparation of functionalized polyolefin materials.Owing to the high abundance and low cost of nickel,nick...The seminal report ofα-diimine palladium and nickel catalysts in 1995 represented a major breakthrough in the preparation of functionalized polyolefin materials.Owing to the high abundance and low cost of nickel,nickel-based catalysts have great application prospects in the industrialization process of olefin coordination polymerization.In this work,various N-aryl substituents with different electronic effects were synthesized and introduced intoα-diimine ligands.The aspreparedα-diimine nickel catalysts showed high polymerization activity(0.9×10^(7)–3.0×10^(7)g·mol^(−1)·h^(−1))in ethylene polymerization,generating polyethylene products with adjustable molecular weights(Mn values:7.4×10^(4)–146.9×10^(4)g·mol^(−1))and branching densities(31/1000 C–68/1000 C).The resulting polyethylene products showed excellent mechanical properties,with high tensile strength(up to 25.0 MPa)and high strain at break values(up to 3890%).The copolymerization of ethylene and polar monomers can also be achieved by these nicekel complexes,ultimately preparing functionalized polyolefins.展开更多
The electronic transport properties of a molecular junction based on doping tailoring armchair-type graphene nanoribbons（AGNRs）with different widths are investigated by applying the non-equilibrium Green＇s function...The electronic transport properties of a molecular junction based on doping tailoring armchair-type graphene nanoribbons（AGNRs）with different widths are investigated by applying the non-equilibrium Green＇s function formalism combined with first-principles density functional theory.The calculated results show that the width and doping play significant roles in the electronic transport properties of the molecular junction.A higher current can be obtained for the molecular junctions with the tailoring AGNRs with W=11.Furthermore,the current of boron-doped tailoring AGNRs with widths W=7 is nearly four times larger than that of the undoped one,which can be potentially useful for the design of high performance electronic devices.展开更多
By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L...By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds.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
Based on the nonequilibrium Green function method and density functional theory calculations, we theoretically investigate the effect of chirality on the electronic transport properties of thioxanthene-based molecular...Based on the nonequilibrium Green function method and density functional theory calculations, we theoretically investigate the effect of chirality on the electronic transport properties of thioxanthene-based molecular switch. The molecule comprises the switch which can exhibit different chiralities, that is, cis-form and trans-form by ultraviolet or visible irradiation. The results clearly reveal that the switching behaviors can be realized when the molecule converts between cis-form and trans-form. ~urthermore, the on-off ratio can be modulated by the chirality of the carbon nanotube electrodes. The maximum on-off ratio can reach 109 at 0.4 V for the armchair junction, suggesting potential applications of this type of junctions in future design of functional molecular devices.展开更多
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.
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Supported by the National Natural Science Foundation of China(No.20673068)
文摘Graphite intercalation compounds（GIC） were tested as an experimental model for studying the electronic effect of carbon support on the catalytic activity and poisoning tolerance of Pt catalyst for direct methanol fuel cells. The GIC samples with different intercalation degrees were prepared by electrolyzing graphite flake in H2SO4 for varying the periods of time. The GIC-supported Pt catalyst was deposited electrochemically. The catalytic activity and poisoning tolerance of the GIC-supported Pt catalysts were evaluated. It was found that GIC with sulfate anion as intercalate was able to catalyze methanol electrooxidation, which could be related to the positive charges generated on the graphite layer upon intercalation. As intercalation degree increased, the catalytic activity of the GIC-supported Pt catalyst decreased while the poisoning tolerance improved. This suggests that electron donation from support to catalyst had great effect on both catalytic activity and poisoning tolerance of Pt catalyst. And intercalation can be adopted as another important way to make modification on carboneous catalyst support.
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supported by the National Natural Science Foundation of China(Nos.22178388 and 22108306)Taishan Scholars Program of Shandong Province(No.tsqn201909065)Chongqing Science and Technology Bureau(No.cstc2019jscx-gksb X0032).
文摘Structural regulation of Pd-based electrocatalytic hydrodechlorination(EHDC)catalyst for constructing high-efficient cathode materials with low noble metal content and high atom utilization is crucial but still challenging.Herein,a support electron inductive effect of Pd-Mn/Ni foam catalyst was proposed via in-situ Mn doping to optimize the electronic structure of the Ni foam(NF),which can inductive regulation of Pd for improving the EHDC performance.The mass activity and current efficiency of Pd-Mn/NF catalyst are 2.91 and 1.34 times superior to that of Pd/NF with 2,4-dichlorophenol as model compound,respectively.The Mn-doped interlayer optimized the electronic structure of Pd by bringing the d-state closer to the Fermi level than Pd on the NF surface,which optimizied the binding of EHDC intermediates.Additionally,the Mn-doped interlayer acted as a promoter for generating H∗and accelerating the EHDC reaction.This work presents a simple and effective regulation strategy for constructing high-efficient cathode catalyst for the EHDC of chlorinated organic compounds.
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.
基金supported by the National Natural Science Foundation of China (51673118, 51273053)the Key Project of the Ministry of Science and Technology of China (2013CB834702)+5 种基金the Natural Science Fund of Guangdong Province (2014A030313659,2014A030306035, 2016A030312002)the Fundamental Research Funds for the Central Universities (2015ZY013)the Innovation and Technology Commission of Hong Kong (ITC-CNERC14SC01)the Science and Technology Plan of Shenzhen (JCYJ20160428150429072)the Fundamental Research Funds for the Central Universities (2017JQ013)Guangdong Innovative Research Team Program (201101C0105067115)
文摘Two novel AIE-active salicylaldehyde azine(SAA) derivatives with a typical excited-state intramolecular proton transfer(ESIPT) process are prepared by introducing electron-withdrawing and donating groups at para-position of phenolic hydroxyl group(CN-SAA and TPA-SAA). The effect of the proton activity in SAA framework on their optical behaviors is investigated spectroscopically. The results from NMR and solvation measurements show that the proton of phenolic hydroxyl group has higher activity when there are electron-withdrawing groups, and the absorption and fluorescence spectra in buffers with different pH also provide the same results. After inviting F. as a nucleophilic probe, this proton activity difference in CN-SAA and TPA-SAA becomes more obvious. The potential application of both molecules is investigated. TPA-SAA exhibits good quantitative sensing ability towards F. with a fluorescence "turn-on" mode, whereas the aggregates of TPA-SAA can selectively and sensitively detect Cu2+ in aqueous solution. From these results, a structure-property relationship is established: the occurrence of ESIPT process will become much easier when linking electron-withdrawing groups at the para-position of phenolic hydroxyl group(e.g., CN-SAA),and it is better to introduce electron-donating groups to enhance the sensing ability towards ions(e.g., TPA-SAA). This work will provide guidance for further design and preparation of AIE-active luminogens with ESIPT process for sensing applications.
基金the National Natural Science Foundation of China(No.22101300)Shandong Natural Science Foundation,China(Nos.ZR2020ME053 and ZR2020QB027)+3 种基金State Key Laboratory of Enhanced Oil Recovery of Open Fund Funded Project(No.2022-KFKT-28)Major Special Projects of CNPC(No.2021ZZ01-05)the Fundamental Research Funds for the Central Universities(Nos.22CX03010A,20CX06007A,and 22CX01002A-1)the Entrepreneurship Practice Project of China University of Petroleum(No.202203007).
文摘The adjustable intermediate binding capacity in electrocatalytic carbon dioxide(CO_(2))reduction is critical for varying the reaction pathways to desired products.Herein,we first report the synthesis of boron-doped amorphous zinc oxide with(B-a-ZnO-Sb)or without antimony nanoparticles embedding(B-a-ZnO)via one-step wet chemical method,which is easy to scale up by enlarging the vessel and increasing feeding.Sb successfully realizes the product switching from CO on B-a-ZnO to formate on B-a-ZnOSb.Both experimental and theoretical results reveal that Sb weakens the charge interaction on Zn atoms.Based on the moderate adsorption of*COOH and strong adsorption of*OCHO and*HCOOH for B-a-ZnO,the foreign Sb weakens the adsorption of these intermediates and brings about a favor formate production instead of CO.This work points out a new direction for the synthesis of amorphous ZnO-based catalysts and provides advanced insights into the aimed selectivity switch for CO_(2)reduction by electronic effect.
基金supported by the National Key R&D Program of China(2021YFA1501700)Fundamental Research Funds for the Central Universities(WK9990000142).
文摘The seminal report ofα-diimine palladium and nickel catalysts in 1995 represented a major breakthrough in the preparation of functionalized polyolefin materials.Owing to the high abundance and low cost of nickel,nickel-based catalysts have great application prospects in the industrialization process of olefin coordination polymerization.In this work,various N-aryl substituents with different electronic effects were synthesized and introduced intoα-diimine ligands.The aspreparedα-diimine nickel catalysts showed high polymerization activity(0.9×10^(7)–3.0×10^(7)g·mol^(−1)·h^(−1))in ethylene polymerization,generating polyethylene products with adjustable molecular weights(Mn values:7.4×10^(4)–146.9×10^(4)g·mol^(−1))and branching densities(31/1000 C–68/1000 C).The resulting polyethylene products showed excellent mechanical properties,with high tensile strength(up to 25.0 MPa)and high strain at break values(up to 3890%).The copolymerization of ethylene and polar monomers can also be achieved by these nicekel complexes,ultimately preparing functionalized polyolefins.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11004156 and 11547172the Science and Technology Star Project of Shaanxi Province under Grant No 2016KJXX-45
文摘The electronic transport properties of a molecular junction based on doping tailoring armchair-type graphene nanoribbons（AGNRs）with different widths are investigated by applying the non-equilibrium Green＇s function formalism combined with first-principles density functional theory.The calculated results show that the width and doping play significant roles in the electronic transport properties of the molecular junction.A higher current can be obtained for the molecular junctions with the tailoring AGNRs with W=11.Furthermore,the current of boron-doped tailoring AGNRs with widths W=7 is nearly four times larger than that of the undoped one,which can be potentially useful for the design of high performance electronic devices.
文摘By use of self-consistent field Xα scattered-wave (SCF-Xα-SW) method, the electronic structure was calculated for four models of Ti4Al14X (X=Al, Fe, Ni and Cu) clusters. The Ti4Al14X cluster was developed based on L12 Al3Ti-base intermetallic compound. The results are presented using the density of states (DOS) and one-electron properties, such as relative binding tendency between the atom and the model cluster, and hybrid bonding tendency between the alloying element and the host atoms. By comparing the four models of Ti4Al14X cluster, the effect of the Fe, Ni or Cu atom on the physical properties of Al3Ti-based L12 intermetallic compounds is analyzed. The results indicate that the addition of the Fe, Ni or Cu atom intensifies the relative binding tendency between Ti atom and Ti4Al14X cluster. It was found that the Fermi level (EF) lies in a maximum in the DOS for Ti4Al14Al cluster; on the contrary, the EF comes near a minimum tn the DOS for Ti4Al14X (X=Fe, Ni and Cu) cluster. Thus the L12 crystal structure for binary Al3Ti alloy is unstable, and the addition of the Fe, Ni or Cu atom to Al3Ti is benefical to stabilize L12 crystal structure. The calculation also shows that the Fe, Ni or Cu atom strengthens the hybrid bonding tendency between the central atom and the host atoms for Ti4Al14X cluster and thereby may lead to the constriction of the lattice of Al3Ti-base intermetallic compounds.
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 11004156the Natural Science Foundation of Shaanxi Province under Grant No 2014JM1025+2 种基金the Science and Technology Star Project of Shaanxi Province under Grant No2016KJXX-38the Special Foundation of Key Academic Subjects Development of Shaanxi Province under Grant No 2008-169the Xi'an Polytechnic University Young Scholar Supporting Plan under Grant No 2013-06
文摘Based on the nonequilibrium Green function method and density functional theory calculations, we theoretically investigate the effect of chirality on the electronic transport properties of thioxanthene-based molecular switch. The molecule comprises the switch which can exhibit different chiralities, that is, cis-form and trans-form by ultraviolet or visible irradiation. The results clearly reveal that the switching behaviors can be realized when the molecule converts between cis-form and trans-form. ~urthermore, the on-off ratio can be modulated by the chirality of the carbon nanotube electrodes. The maximum on-off ratio can reach 109 at 0.4 V for the armchair junction, suggesting potential applications of this type of junctions in future design of functional molecular devices.
