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159篇 您的检索式:关键字=Density functional theory
    题名 作者 年代 出处 被引量
1Li-Si合金中间相作为锂离子电池负极材料的研究(英文)显示文摘采用基于密度泛函理论的第一性原理平面波赝势方法计算了Li-Si各种合金相的物理性质和电化学性能。结果表明:除了在反应过程中生成传统的固态电解质SEI膜之外,形成的Li12Si7合金相也是部分导致首次不可逆容量损失的重要原因。另外,采用射频磁控溅射制备了纯Si薄膜电极,并运用XRD、循环伏安CV、恒流充放电CC表征和测试了材料的结构和电化学性能,结果表明首次不可逆容量损失非常大,无定型结构能有效抑制体积膨胀和改善循环性能。侯贤华 胡社军 汝强 张志文 2010稀有金属材料与工程2010,39,12:9
2Progress on tilted axis cranking covariant density functional theory for nuclear magnetic and antimagnetic rotation显示文摘Magnetic rotation and antimagnetic rotation are exotic rotational phenomena observed in weakly deformed or near-spherical nuclei, which are respectively interpreted in terms of the shears mechanism and two shearslike mechanism. Since their observations, magnetic rotation and antimagnetic rotation phenomena have been mainly investigated in the framework of tilted axis cranking based on the pairing plus quadrupole model. For the last decades, the covariant density functional theory and its extension have been proved to be successful in describing series of nuclear ground-states and excited states properties, including the binding energies, radii, single-particle spectra, reso- nance states, halo phenomena, magnetic moments, magnetic rotation, low-lying excitations, shape phase transitions, collective rotation and vibrations, etc. This review will mainly focus on the tilted axis cranking covariant density functional theory and its application for the magnetic rotation and antimagnetic rotation phenomena.孟杰 彭婧 张双全 赵鹏巍 2013Frontiers of physics2013,8,1:9
3Molecular electronegativity in density functional theory (II) --Direct calculation of group electronegativity and the atomic charges in a group显示文摘On the basis of a more precise expression of the atomic effective electronegativity deduced from the density functional theory and electronegativity equalization principle, a new scheme for calculating the group electronegativity and the atomic charges in a group is proposed and programed, and various parameters of electronegativity and hardness are given for some common atoms. Through calculation, analysis and comparison of more than one hundred groups, it is shown that the results from this scheme are reasonable and may be extended.杨忠志 沈尔忠 1996Science China Chemistry1996,39,1:7
4Insight into the catalytic activity of MXenes for hydrogen evolution reaction显示文摘MXenes have exhibited great potential as cost-effective electrocatalysts for hydrogen evolution reaction(HER). However, insight into the origin of activity is still missing. Herein, on the basis of a systematical investigation of the HER performance of 20 MXenes(M_2NO_2 and M_2CO_2, M = Sc, Ti, V, Cr, Zr, Nb, Mo,Hf, Ta and W), a Fermi-abundance model is proposed to understand variation of the activity in different MXenes. It is found that the occupied p electronic states of surface O atoms play a decisive role in the HER activity of MXenes. More importantly, Ti_2NO_2 and Nb_2NO_2 are found to be promising HER electrocatalysts with the free energy for hydrogen adsorption close to zero. This work not only provides possible catalysts for HER, the developed Fermi-abundance model but also is applicable to other two-dimensional materials and may serve as a simple descriptor of the intrinsic HER activity.Xiaowan Bai Chongyi Ling Li Shi Yixin Ouyang Qiang Li Jinlan Wang 2018Science Bulletin2018,63,21:6
5Molecular electronegativity in density functional theory (VI) --Atom-bond electronegativity equalization model显示文摘Based on the density functional theory and partitioning the molecular electron density ρ(r) into atomic electronic densities and bond electronic densities,the expressions of the total molecular energy and the 'effective electronegativity' of an atom or a bond in a molecule are obtained.The atom bond electronegativity equalization model is then proposed for the direct calculation of the total molecular energy and the charge distribution of large molecules.Practical calculations show that the atom bond electronegativity equalization model can reproduce the corresponding ab initio values of the total molecular energies and charge distributions for a series of large molecules with a very satisfactory accuracy.杨忠志 王长生 唐敖庆 1998Science China Chemistry1998,41,3:5
6Molecular electronegativity in density functional theory (I)——Direct calculation of atomic charges in a molecule via electronegativity equalization principle显示文摘On the basis of electronegativity expressed in density functional theory and electronegativity equalization principle, a new scheme for calculating the atomic charges in a molecule has been proposed and designed, which gives a new scale of the atomic electronegativity and hardness in a certain molecular environment and takes the harmonic mean electronegativity as a reference value of the molecular electronegativity so that the multiple-regression and nonuniform parameters in the original method are avoided. This approach can be easily and widely applied to the calculation of atomic charges for a big molecule and quite good results of atomic charges in some illustrated molecules are obtained as compared with those from the ab initio STO-3G SCF calculations.杨忠志 沈尔忠 1995Science China Chemistry1995,38,5:5
7Ternary Ni-Co-Fe oxyhydroxide oxygen evolution catalysts:Intrinsic activity trends,electrical conductivity,and electronic band structure显示文摘Nickel-,cobalt-,and iron-based(oxy)hydroxides comprise the most-commonly studied electrocatalysts for the oxygen-evolution reaction(OER)in alkaline solution.A fundamental understanding of composition-structure-activity relationships for mixed-metal Ni-Co and Ni-Co-Fe(oxy)hydroxides is important to guide the design of advanced OER catalysts.Here we use cyclic voltammetry,chronopotentiometry,inductively-coupled plasma-optical emission spectroscopy,and in situ electrical conductivity measurements to characterize the properties and activity of various compositions of Ni-Co-Fe(oxy)hydroxides prepared by cathodic co-electrodeposition.Consistent with previous studies,we find Fe is essential for the mixed-metal(oxy)hydroxides to achieve high OER activity.In the rigorous absence of Fe(achieved by using specially cleaned electrolytes),the most-active Ni-Co(oxy)hydroxide composition has an OER turn-over frequency only twice that ofpure Co(oxy)hydroxide,suggesting minimal synergism between the two metals.The addition of Co to Ni-Fe(oxy)hydroxides shifts the onset of electrical conductivity to lower potentials,but has little effect on the intrinsic OER activity,with the most-active Ni-Co-Fe(oxy)hydroxide having an OER turn-over frequency only -1.5 times that of the Ni-Fe(oxy)hydroxides.The magnitudes of the electrical conductivities are similar for all the compositions measured.Density-functional-theory-calculated projected density of states show a significant contribution of all chemical elements at the valence band edge of the mixed-metal oxyhydroxide electronic structure,demonstrating significant electronic hybridization between the elements.The calculations suggest the involvement of all the elements in modulating the electronic structure at putative Fe-based active sites that are probably located at edges or defects in the two-dimensional oxyhydroxide sheets.Michaela Burke Stevens Lisa J. Enman Ester Hamal Korkus Jeremie Zaffran Christina D. M. Trang James Asbury Matthew G. Kast Maytal Caspary Toroker Shannon W. Boettcher 2019Nano Research2019,12,9:5
8Electrochemical reactions at the electrode/solution interface:Theory and applications to water electrolysis and oxygen reduction显示文摘Theoretical simulations on complex electrochemical processes have been developed on the basis of the understanding in electrochemistry,which has benefited from quantum mechanics calculations.This article reviews the recent progress on the theory and applications in electrocatalysis.Two representative reactions,namely water electrolysis and oxygen reduction,are selected to illustrate how the theoretical methods are applied to electrocatalytic reactions.The microscopic nature of these electrochemical reactions under the applied potentials is described and the understanding of the reactions is summarized.The thermodynamics and kinetics of the electrochemical reactions affected by the interplay of the electrochemical potential,the bonding strength and the local surface structure are addressed at the atomic level.Fang, Ya Hui Liu, Zhi Pan 2010Science China Chemistry2010,53,3:5
9Hexagonal boron nitride nanosheet for effective ambient N2 fixation to NH3显示文摘Industrial production of NH3 from N2 and H2 significantly relies on Haber-Bosch process,which suffers from high energy consume and CO2 emission.As a sustainable and environmentally-benign alternative process,electrochemical artificial N2 fixation at ambient conditions,however,is highly required efficient electrocatalysts.In this study,we demonstrate that hexagonal boron nitride nanosheet (h-BNNS) is able to electrochemically catalyze N2 to NH3.In acidic solution,h-BNNS catalyst attains a high NH3 formation rate of 22.4 μg·h-1·mg-1cat.and a high Faradic efficiency of 4.7% at-0.75 V vs.reversible hydrogen electrode,with excellent stability and durability.Density functional theory calculations reveal that unsaturated boron at the edge site can activate inert N2 molecule and significantly reduce the energy barrier for NH3 fonmation.Ya Zhang Huitong Du Yongjun Ma Lei Ji Haoran Guo Ziqi Tian Hongyu Chen Hong Huang Guanwei Cui Abdullah M. Asiri Fengli Qu Liang Chen Xuping Sun 2019Nano Research2019,12,4:5
10Group VB transition metal dichalcogenides for oxygen reduction reaction and strain-enhanced activity governed by p-orbital electrons of chalcogen显示文摘Developi ng alter native oxyge n reducti on reactio n (ORR) catalysts to replace precious Pt-based metals with abundant materials is the key challe nge of commercial application of fuel cells. Owing to their various compositi ons and tun able electronic properties, transition metal dichalcogenides (TMDs) have the great potential to realize high-efficiency catalysts for ORR. Here, various 3R-phase dichalcogenides of group VB and VIB transition metals (MX2, M = Nb, Ta, Mo, W;X = S, Se, Te) are investigated for ORR catalysts by using density functional theory calculations. The computed over-potentials of group VB TMDs are much less than those of group VIB TMDs. For group VB TMDs, a volcano-type plot of ORR catalytic activity is established on the adsorption energies of *OH, and NbS2 and TaTe2 exhibit best ORR activity with an oveepotential of 0.54 V. To achieve even better activity, strain engineering is performed to tune ORR catalytic activity, and the minimum over-potential of 0.43 V can be realized. We further dem on strate that the shift of p orbital center of surface chalcoge n elements under strain is responsible for tuning the catalytic activity of TMDs.Shuyang Zhao Ke Wang Xiaolong Zou Lin Gan Hongda Du Chengjun Xu Feiyu Kang Wenhui Duan Jia Li 2019Nano Research2019,12,4:4
11Insight into the formation mechanism of levoglucosenone in phosphoric acid-catalyzed fast pyrolysis of cellulose显示文摘The catalytic fast pyrolysis of cellulose impregnated with phosphoric acid (H3PO4) offers a promising method for the selective production of levoglucosenone (LGO),a valuable anhydrosugar product.However,the fundamental mechanism for selective LGO formation is unclear.Herein,quantum chemistry calculations and catalytic fast pyrolysis experiments were performed to reveal the formation mechanism of LGO in H3PO4-catalyzed cellulose pyrolysis.H3PO4 significantly decreased the energy barriers of the pyrolytic reactions and altered the competitiveness of the LGO formation pathways,promoting LGO formation.Through different pathways in the non-catalytic and H3P04-catalyzed conditions,LGO is mainly produced from the primary decomposition of glucose units of cellulose and secondary conversion of levoglucosan.The major catalytic formation pathways of LGO comprise similar reactions,with dehydration at the 3-OH+2-H site as the rate-determining step.Importantly,secondary conversion of 1,4;3,6-dianhydro-α-D-glucopyranose is not feasible for LGO formation,in contrast to previous reports.In addition,a high degree of polymerization is beneficial for the selectivity of LGO formation in the catalytic process,because the glycosidic bond is important for the formation of the bicyclic structure (1,5-and1,6-acetal rings).Bin Hu Qiang Lu Yu-ting Wu Wen-luan Xie Min-shu Cui Ji Liu Chang-qing Dong Yong-ping Yang 2020Journal of Energy Chemistry2020,29,4:4
12Transition-metal-doped NiSe2 nanosheets towards efficient hydrogen evolution reactions显示文摘Transition metal diselenides are promising electrocatalysts for hydrogenevolution and therefore different approaches have been proposed to enhancetheir catalytic activity. Herein, we describe systematic studies of the dependenceof transition-metal doping on the catalytic activity of NiSe2 by first principlescalculations, where Fe is demonstrated to be the best candidate element to tunethe electrocatalytic activity of NiSe2 with lower AGH. values and increasedelectrical conductivity. To provide further experimental evidence, Fe-dopedNiSe2 porous nanosheets grown on carbon cloth are successfully developed.These nanosheets show significantly improved efficiency for hydrogen evolutionreactions compared to their un-doped counterpart. The optimized Ni0.sFe0.2Se2electrocatalyst gives rise to a current density of 10 mA.cm-2 at a very lowoverpotential of 64 mV with outstanding long-term stability. The present strategyof doping NiSe2-based electrocatalysts with transition metals paves a newpathway for the design and synthesis of electrocatalysts for large-scale electro-chemical energy applications.Tongtong Wang Daqiang Gao Wen Xiao Pinxian Xi Desheng Xue John Wang 2018Nano Research2018,11,11:4
13Recent advances on first-principles modeling for the design of materials in CO2 capture technologies显示文摘Novel technologies in consideration of industrial sustainability(IS)are in urgent need to satisfy the increasing demands from the society.IS realizes the production of materials while maintaining environmental and resource sustainability.The chemical materials used in CO2 capture and storage(CCS)technologies play a significant role in the disposal of greenhouse gas emissions coming from large stationary fossil-fired power plants,which breaks the principle of IS and brings severe environmental problems.This study aims at providing a detailed review of first-principles modeling(density functional theory,DFT)of materials in CO2 capture technologies.DFT analysis provides insight into the atomic properties of the studied systems and builds an efficient guidance of the future design of the materials used in CO2 capture technologies.Major materials including oxygen carriers,metal organic frameworks,membranes,zeolites,ionic liquids and some other promising candidates are considered.The computational studies bring the outcomes of the adsorption behaviors,structural characteristics and accurate force fields of the studied materials in short turn-around times at low cost.This review can stimulate the design of novel materials with specific target of CO2 capture and promote the industrial sustainability of fossil fuel combustion technologies.Yue Yuan Huabei You Luis Ricardez-Sandoval 2019Chinese Journal of Chemical Engineering2019,27,7:4
14Insight into room-temperature catalytic oxidation of NO by CrO_2(110):A DFT study显示文摘The NO oxidation processes on CrO_2(110) was investigated by virtue of DFT + U calculation together with microkinetic analysis, aiming to uncover the reaction mechanism and activity-limiting factors for CrO_2 catalyst. It was found that NO oxidation on CrO_2(110) has to be triggered with the lattice Obri involved(Mars-van Krevelen mechanism) rather than the Langmuir-Hinshelwood path occurring at the Cr_(5 c) sites alone. Specifically, the optimal reaction path was identified. Quantitatively, the microkinetic analysis showed that CrO_2(110) can exhibit a high turnover rate of 0.978 s^(-1) for NO oxidation at room temperature.Such an activity could originate from the bifunctional synergetic catalytic mechanism, in which the Cr_(5c)sites can exclusively adsorb NO and the Obri is very reactive and provides oxidative species. However, it is worth noting that, as the reactive Obri tightly binds NO_2, the nitrate species was found to be difficult removed and constituted the key poisoning species, eventually limiting the overall activity of CrO_2. This work demonstrated the considerable catalytic ability of CrO_2 for NO oxidation at room temperature, and the understanding may facilitate the further design of more active Cr-based catalyst.Jiamin Jin Jianfu Chen Haifeng Wang Peijun Hu 2019Chinese Chemical Letters2019,30,3:4
15In situ redox growth of mesoporous Pd-Cu2O nanoheterostructures for improved glucose oxidation electrocatalysis显示文摘Interfaces of metal-oxide heterostructured electrocatalyst are critical to their catalytic activities due to the significant interfacial effects. However, there are still obscurities in the essence of interfacial effects caused by crystalline defects and mismatch of electronic structure at metal-oxide nanojunctions. To deeply understand the interfacial effects, we engineered crystalline-defect Pd-Cu2O interfaces through nonepitaxial growth by a facile redox route. The Pd-Cu2O nanoheterostructures exhibit much higher electrocatalytic activity toward glucose oxidation than their single counterparts and their physical mixture,which makes it have a promising potential for practical application of glucose biosensors.Experimental study and density functional theory(DFT) calculations demonstrated that the interfacial electron accumulation and the shifting up of d bands center of Cu-Pd toward the Fermi level were responsible for excellent electrocatalytic activity. Further study found that Pd(3 1 0) facets exert a strong metaloxide interface interaction with Cu2O(1 1 1) facets due to their lattice mismatch. This leads to the sinking of O atoms and protruding of Cu atoms of Cu2O, and the Pd crystalline defects, further resulting in electron accumulation at the interface and the shifting up of d bands center of Cu-Pd, which is different from previously reported charge transfer between the interfaces. Our findings could contribute to design and development of advanced metal-oxide heterostructured electrocatalysts.Ying Guo Jianwen Liu Yi-Tao Xu Bo Zhao Xuewan Wang Xian-Zhu Fu Rong Sun Ching-Ping Wong 2019Science Bulletin2019,64,11:3
16A mathematical aspect of Hohenberg-Kohn theorem显示文摘The Hohenberg-Kohn theorem plays a fundamental role in density functional theory, which has become the most popular and powerful computational approach to study the electronic structure of matter.In this article, we study the Hohenberg-Kohn theorem for a class of external potentials based on a unique continuation principle.Aihui Zhou 2019Science China Mathematics2019,62,1:3
17Growth behavior and electronic properties of Ge_(n+1) and AsGe_n(n = 1–20) clusters: a DFT study显示文摘We present a systematic computational study based on the density functional theory(DFT) aiming to high light the possible effects of one As doping atom on the structural, energetic, and electronic properties of different isomers of Ge_(n+1) clusters with n = 1–20 atoms. By considering a large number of structures for each cluster size, the lowest-energy isomers are determined. The lowest-energy isomers reveal three-dimensional structures starting from n = 5. Their relative stability versus atomic size is examined based on the calculated binding energy, fragmentation energy, and second-order difference of energy. Doping Ge_(n+1) clusters with one As atom does not improve their stability. The electronic properties as a function of the atomic size are also discussed from the calculated HOMO–LUMO energy gap, vertical ionization potential, vertical electron affinity, and chemical hardness. The obtained results are significantly affected by the inclusion of one As atom into a Gen cluster.M.Benaida K.E.Aiadi S.Mahtout S.Djaadi W.Rammal M.Harb 2019Journal of Semiconductors2019,40,3:3
18Structure and stability of (AlN)_n clusters显示文摘AIN and Al2N2 have been observed in the record of time-of-flight mass-spectra as positive ions. Associating with density functional theory(DFT) B3LYP method with 6-31G* basis set, we have carried out the optimizing calculations of the geometry, electronic state and vibrational frequency for (AIN)n (n = 1-15) clusters, moreover, discussed the character of the chemical bond and thermodynamical stability and explained the experimental mass spectra. The results show that there do not exist AI-AI and N-N bonds and only exists AI-N bond in the ground state structures of (AIN)n clusters; and the 'magical number' regularity of (AIN)n is those whose atom number Is 4, 8, 12,16, 20, etc, all of which are times of four.武海顺 张聪杰 许小红 郑兰荪 张乾二 2000Science China Chemistry2000,43,6:2
19Molecular Spectra and Dissociation Dynamics of Oxalyl Chloride: Effect of External Electrical Fields显示文摘Oxalyl chloride is a highly toxic and caustic substance, which widely exists in human production and life as a kind of volatile organic compound. Based on the density functional theory B3 LYP at 6-311++G(d, p) level, the influences of external electric field on the bond length, bond energy, dipole moment and dissociation mechanism are optimized. The results indicate that the C_1–Cl_3 bond length increases while the C_4–Cl_6 bond decreases. At the same time, the carbon-carbon bond length gradually increases with the increase of electric field. The total energy decreases while the dipole moment gradually increases with the increase of electric field. In the infrared spectra, the vibration frequency of the carbon-chlorine(C_4–Cl_6) bond decreases while the vibration frequency of the carbon-oxygen bond increases. In the ultraviolet-visible spectra, the wavelength of the strongest absorption peak increases as the external electric field increases and shows an observable red shift phenomenon. Additionally, single point energies of oxalyl chloride along the carbon-carbon bond are scanned with the equation-of-motion coupled cluster method restricted to single and double excitations(EOM-CCSD) method and the potential energy curves under different external electric fields are obtained. The dissociation barrier in potential energy curve decreases because of the breakage of carbon-carbon bond with the increase of external electric field. These results provide reference for further researches on the properties of oxalyl chloride and offer a theoretical basis for the study of oxalyl chloride degradation.尹文怡 刘玉柱 周冯斌 布玛丽亚.阿布力米提 2019Chinese Journal of Structural Chemistry2019,38,4:2
20Study on the Physical and Dissociation Properties of Disulfur Dichloride under Electric Fields显示文摘Disulfur dichloride is a hazardous substance, which is irritating to the eyes. It is significant to study the physical and dissociation properties under external electric fields. The bond length, energy, dipole moment, orbital energy level distribution, infrared spectra and dissociation properties of disulfur dichloride molecule under different external fields are obtained by using the density functional theory at the B3LYP/6-311++G(d, p) basis set level. In addition, ultraviolet-visible absorption spectra of the molecule in different electric fields are studied with configuration interaction-single excitation(CIS)/6-311++G(d, p) method. According to the results, it has been found that as the electric field exerted along the positive direction of the z-axis increases, the two sulfur-chlorine(S-Cl) bond lengths become longer and tend to break, while the sulfur-sulfur(S-S) bond length becomes shorter and the energy gap decreases. The infrared spectrum and ultraviolet-visible absorption spectra both exhibit red shift under electric field. Moreover, by scanning the potential energy surface of disulfur dichloride about S-Cl bond, the dissociation barrier decreases with the increase of positive electric field. When the external electric field arrives at 0.040 atomic units, the barrier disappears, meaning the dissociation of disulfur dichloride. The present results offer an important reference to further study of disulfur dichloride.瞿荧飞 刘玉柱 尹文怡 张启航 布玛丽亚·阿布力米提 2019Chinese Journal of Structural Chemistry2019,38,8:2
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