密度泛函活性理论中的信息论方法（英文）

密度泛函活性理论(DFRT)运用简单的密度泛函探讨和定量化分子的反应活性,是近来发展起来的一个关于分子活性理论的新方法。在新近的文献中,这样的简单密度泛函的例子包括香农熵,费舍尔信息以及其它来自信息论中的密度泛函。本文综述了DFRT信息论方法的原理,包括物理信息极小原理、最小信息增益原理和信息守恒原理。总结了DFRT信息论方法在电子密度、形态密度和分子中的原子三种表述下的理论框架。此外,还介绍了运用信息论方法在定量描述空间位阻效应、亲电性、亲核性和区域选择性中的突出应用,以及对亲电芳香取代反应的邻对间位取代效应的起源和本质提供的一个全新诠释。最后简要地展望了该领域的几个可能的未来发展方向。

双官能团硫脲催化丙交酯开环聚合反应的理论研究

用密度泛函理论在B3LYP/6-31G(d)水平上研究了双官能团硫脲催化丙交酯开环聚合反应的微观机理.讨论了催化聚合反应的两条可能路径:路径A和路径B.计算结果表明沿路径A进行的开环聚合反应在能量上是有利的.从理论上证实了催化剂在聚合反应中所起的双官能团催化作用,即氨基活化引发剂,硫脲活化单体,通过两个基团共同作用,完成催化开环.

羰基化合物在Si(100)表面[2+2]环加成和α-H裂解反应的选择性(英文)

最近研究表明:丙酮能与半导体Si(100)表面发生[2+2]环加成和α-H裂解反应形成相应的Si―C键或Si―O键,在半导体材料的合成方面具有重要意义.为进一步弄清不同羰基化合物在Si(100)表面的反应机理,本文应用密度泛函理论方法在B3LYP/6-311++G(d,p)//6-31G(d)水平上较为系统地研究了一系列羰基化合物CH3COR(R=CH3,H,C2H5,C6H5)与Si(100)表面的反应.研究结果表明:不论是[2+2]环加成反应还是α-H裂解反应都对应较低的反应势垒(小于25kJ·mol-1);环加成反应的势垒比α-H裂解反应的势垒略高;羰基上的取代基对反应势垒的影响较少;α-H裂解反应产物为动力学和热力学控制产物;对丁酮来说,1-位和3-位H原子的裂解反应都比较容易,势垒相差很小.这些结果表明羰基化合物与Si(100)表面的反应将得到多种产物.

Enhanced Oxygen Evolution Reaction Performance by Dynamic Adsorption of Intermediates on C_(2)N-Supported Single Atom Catalysts

The dynamic adsorption of possible intermediates on single-atom catalysts(SACs)under working condition plays a key role in the electrocatalytic performance by the oxygen evolution reaction(OER),and therefore the performance of the dynamic adsorption should be fully considered in the theoretical screening of potential SACs.Based on density functional theory calculations,the OER performance of 27 types of C_(2)N-supported single transition metal atoms(TM@C_(2)N)is systematically investigated without and with considering the dynamic adsorption of possible intermediates.Without considering dynamic adsorption,only Rh@C_(2)N and Ni@C_(2)N are screened out as good catalysts.However,by further considering the dynamic adsorption configurations of possible intermediates,more promising TM@C_(2)N SACs including Fe(Co,Ni,Ru,Rh,Ir)@C_(2)N toward the OER are screened out.The presence of the intermediates(*HO,*O)on SACs could shift their d band center toward lower energy level,which makes the interaction between the adsorbate and SACs moderate and thus enhances their OER performance.The present work is instructive for further screening and designing of efficient single-atom catalysts for the oxygen evolution reaction.

Theoretical insights into oxygen reduction reaction on Au-based single-atom alloy cluster catalysts

Developing highly active alloy catalysts that surpass the performance of platinum group metals in the oxygen reduction reaction(ORR)is critical in electrocatalysis.Gold-based single-atom alloy(AuSAA)clusters are gaining recognition as promising alternatives due to their potential for high activity.However,enhancing its activity of AuSAA clusters remains challenging due to limited insights into its actual active site in alkaline environments.Herein,we studied a variety of Au_(54)M_(1) SAA cluster catalysts and revealed the operando formed MO_(x)(OH)_(y) complex acts as the crucial active site for catalyzing the ORR under the basic solution condition.The observed volcano plot indicates that Au_(54)Co_(1),Au_(54)M_(1),and Au_(54)Ru_(1) clusters can be the optimal Au_(54)M_(1) SAA cluster catalysts for the ORR.Our findings offer new insights into the actual active sites of AuSAA cluster catalysts,which will inform rational catalyst design in experimental settings.

Density functional theory study of influence of impurity on electronic properties and reactivity of pyrite

The electronic property of pyrite supercell containing As,Se,Te,Co or Ni hetero atoms were calculated using density functional theory（DFT）,and the reactivities of pyrite with oxygen and xanthate were discussed by frontier orbital methods.The cell volume expands due to the presence of impurity.Co and Ni mainly affect the bands near Fermi levels,while As mainly affects the shallow and deep valence bands,and Se and Te mainly affect the deep valence bands.Electronic density analysis suggests that there exists a strong covalent interaction between hetero atom and its surrounding atoms.By frontier orbital calculation,it is suggested that As,Co and Ni have greater influence on the HOMO and LUMO of pyrite than Se and Te.In addition,pyrite containing As,Co or Ni is easier to oxidize by oxygen than pyrite containing Se or Te,and pyrite containing Co or Ni has greater interaction with collector.These are in agreement with the observed pyrite practice.

Experimental and Theoretical Study of Hydrogen Atom Abstraction from C2H6 and C4H10 by Zirconium Oxide Clusters Anions

The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H- and Zr3O7H- are observed after the reaction. Den-sity functional theory calculations indicate that the hydrogen abstraction is favorable in the reaction of Zr2O5- with C2H6, which supports that the observed Zr2O5H- and Zr3O7H- are due to hydrogen atom abstraction from the alkane molecules. This work shows a newpossible pathway in the reaction of zirconium oxide cluster anions with alkane molecules.

CuCl2催化(2-甲基辛烷-2，3-二烯-4-基)磷酸乙酯氯代环化反应机理理论研究

采用密度泛函理论(DFT)中的B3LYP方法对CuCl2催化的(2-甲基辛烷-2,3-二烯-4-基)磷酸乙酯氯代环化反应机理进行了理论研究.在6-31+G(d)基组水平上对反应机理中所有反应物、过渡态、中间体和产物进行了优化,通过能量和振动频率分析以及IRC计算证实了中间体和过渡态的合理性.在相同基组水平上应用自然键轨道(NBO)理论和分子中的原子(AIM)理论分析了复合物的成键特征和轨道间相互作用.反应物R和催化剂CuCl2可通过IA和IB两条可行反应通道生成中间体IM9,控制步骤活化能分别是129.61和142.10kJ/mol.中间体IM9到产物P也有两条反应路径PA和PB,控制步骤活化能分别是179.55和9.83kJ/mol.整个反应机理中IA→PB和IB→PB反应通道可能同时发生,反应控制步骤活化能最低反应通道为IA→PB.

Ligand Size Effect on PdLn Oxidative Addition with Aryl Bromide： A DFT Study

The process and mechanism of the ligand volume controlled Pd（PR3）2 （PR3=PH3, PMe3, and PtBu3） oxidative addition with aryl bromide were investigated, using density functional theory method with the conductor-like screening model. Association pathway and dissocia-tion pathway were investigated by the comparison of several energies. The cleavage energy of Pd（PR3）2 complex was calculated, as well as the oxidative addition reaction barrier energy of Pd（PR3）n （n=1,2） with aryl bromide in N,N-dimethylformamide solvent. This study proved that the ligands volume possessed a great impact on the mechanism of oxidative addition： less bulky ligand palladium associated with aryl bromide via two donor ligands,but larger bulky ligand palladium coordinated via monoligand.

TDDFT Study on Different Sensing Mechanisms of Similar Cyanide Sensors Based on Michael Addition Reaction

The solvents and substituents of two similar fluorescent sensors for cyanide, 7-diethylamino- 3-formylcoumarin （sensor a） and 7-diethylamino-3-（2-nitrovinyl）coumarin （sensor b）, are proposed to account for their distinct sensing mechanisms and experimental phenomena. The time-dependent density functional theory has been applied to investigate the ground states and the first singlet excited electronic states of the sensor as well as their possible Michael reaction products with cyanide, with a view to monitoring their geometries and photophysieal properties. The theoretical study indicates that the protic water solvent could lead to final Michael addition product of sensor a in the ground state, while the aprotic acetonitrile solvent could lead to carbanion as the final product of sensor b. Furthermore, the Michael reaction product of sensor a has been proved to have a torsion structure in its first singlet excited state. Correspondingly, sensor b also has a torsion structure around the nitrovinyl moiety in its first singlet excited state, while not in its carbanion structure. This could explain the observed strong fluorescence for sensor a and the quenching fluorescence for the sensor b upon the addition of the cyanide anions in the relevant sensing mechanisms.

Analysis of Potential Energy Surface for Butanone Isomerization

The potential energy surfaces for butanone isomerization have been investigated by density function theory calculation. Six main reaction pathways are confirmed using the intrinsic reaction coordinate method, and the corresponding isomerization products are 1-buten-2-ol, 2-buten-2-ol, butanal or 1-buten-l-ol, methyl 1-propenyl ether, methyl allyl ether, and ethyl vinyl ether, respectively. Among them, there are three pathways through butylene oxide, indicating butylene oxide is an important intermediate product during butanone isomer ization. The calculated vertical ionization energies of the reactant and its products are in a good agreement with the experimental values available. From the consideration for the relative energies Of transition states and the number of high-energy barriers we infer that the reaction pathway butanone-＊l-buten-2-ol---2-buten-2-oi is the most competitive. The obtained results are informative for future studies on isomerization of ketone molecules.

Effect of Pd doping on CH_4 reactivity over Co_3O_4 catalysts from density-functional theory calculations

Palladium oxide(PdOx)and cobalt oxide(Co3O4)are efficient catalysts for methane(CH4)combustion,and Pd‐doped Co3O4catalysts have been found to exhibit better catalytic activities,which suggest synergism between the two components.We carried out first‐principles calculations at the PBE+U level to investigate the Pd‐doping effect on CH4reactivity over the Co3O4catalyst.Because of the structural complexity of the Pd‐doped Co3O4catalyst,we built Pd‐doped catalyst models using Co3O4(001)slabs with two different terminations and examined CH4reactivity over the possible Pd?O active sites.A low energy barrier of0.68eV was predicted for CH4dissociation over the more reactive Pd‐doped Co3O4(001)surface,which was much lower than the0.98and0.89eV that was predicted previously over the more reactive pure Co3O4(001)and(011)surfaces,respectively.Using a simple model,we predicted CH4reaction rates over the pure Co3O4(001)and(011)surfaces,and Co3O4(001)surfaces with different amounts of Pd dopant.Our theoretical results agree well with the available experimental data,which suggests a strong synergy between the Pd dopant and the Co3O4catalyst,and leads to a significant increase in CH4reaction rate.

Theoretical study of stability of metal-N_4 macrocyclic compounds in acidic media

Fe and Co porphyrins and phthalocyanines are excellent catalysts for the oxygen reduction reaction （ORR） and are promising alternatives to Pt in fuel cells. However, the stability of these molecular catalysts in acidic media is poor. This study explores whether demetalation through proton ex- change causes these metal macrocyclic catalysts to be unstable in acidic media. We first present a theoretical scheme for investigating exchange reactions of metal ions in metal macrocyclic com- pounds with protons in acidic media. The equilibrium concentrations of metal ions in solution when various metalloporphyrins （MPs） and metallophthalocyanines （MPcs） are brought into contact with a strongly acidic solution （pH = 1） were then estimated using density functional theory calculations; these values were used to evaluate the stability of these metal macrocyclic compounds against demetalation in acidic media, The results show that Fe, Co, Ni, and Cu phthalocyanines and porphy- rins have considerable resistance to exchange with protons, whereas Cr, Mn, and Zn phthalocya- nines and porphyrins easily undergo demetalation through ion exchange with protons, This sug- gests that the degradation in the ORR activity of Fe and Co macrocyclic molecular catalysts and of carbon materials doped with Fe（Co） and nitrogen, which are believed to have metal-nitrogen coor- dination structures similar to those of macrocyclic molecules as ORR catalytic centers, is not the result of replacement of metal ions by protons. The calculation results show that electron-donating substituents could enhance the stability of Fe and Co phthalocyanines.

Light-Induced Reaction of Benzene with Carbonates

We found an ultraviolet （UV）-light induced formation of biphenyl and sodium benzoate from benzene and sodium carbonate. The reaction happens in the interface of benzene and aqueous solution at the room temperature. After 5 h of UV-light exposure, 11.4% of initial amount of 4.4 g （5.0 mL） benzene are converted to biphenyl and sodium benzoate, which are distributed in benzene and aqueous solution, respectively. Using density function theory （DFT） and time dependent DFT, we have investigated the mechanism of this light-induced reaction, and found that the sodium carbonate is not only a reactant for the formation of sodium benzoate, but also a catalyst for the formation of biphenyl.

High halogenated nitrobenzene hydrogenation selectivity over nano Ir particles

The selective hydrogenation of halogenated nitrobenzene over noble metal catalysts(Pd, Pt, and Ir) has attracted much attention owing to its high efficiency and environmental friendliness. However, the effect of size on the catalytic performance varies among different metal catalysts. In this study, sub-nano(<3 nm) Ir and Pd particles were prepared, and their catalytic properties for hydrogenation of halogenated nitrobenzene were evaluated.Results show that high selectivity(N 99%) was achieved over small Ir nanoparticles, in which the selectivity over the Pd with same size was much lower than that on Ir nanoparticles. Meanwhile, Ir and Pd have different hydrogen consumption rates and reaction rates. Density functional theory calculations showed that p-chloronitrobenzene(CNB) has different adsorption properties on Ir and Pd. The distance between oxygen(cholorine) and Ir is much shorter(longer) than that between oxygen and Pd. The reaction barriers of dechlorination of p-CNB and p-chloroaniline over different Ir models are much larger than those on Pd. Especially,lower coordination of Ir leads to larger barriers of dechlorination reaction. These theoretical results explain the difference between Ir and Pd on hydrogenation of halogenated nitrobenzene.

Influence of surface strain on activity and selectivity of Pd-based catalysts for the hydrogenation of acetylene: A DFT study

The effects of surface strain and subsurface promoters, which are both important factors in heterogeneous catalysis, on catalytic selectivity and activity of Pd are examined in this study by considering the selective hydrogenation of acetylene as an example. Combined density functional theory calculations and microkinetic modeling reveal that the selectivity and activity of the Pd catalyst for acetylene hydrogenation can both be substantially influenced by the effects of Pd lattice strain variation and subsurface carbon species formation on the adsorption properties of the reactants and products. It is found that the adsorption energies of the reactants and products are, in general, linearly scaled with the lattice strain for both pristine and subsurface carbon atom-modified Pd（111） surfaces, except for the adsorption of C_2H_2 over Pd（111）-C. The activity for ethylene formation typically corresponds to the region of strong reactants adsorption in the volcano curve; such an effect of lattice strain and the presence of subsurface promoters can improve the activity of the catalyst through the weakening of the adsorption of reactants. The activity and selectivity for Pd（111）-C are always higher than those for the pristine Pd（111） surfaces with respect to ethylene formation. Based on the results obtained, Pd-based catalysts with shrinking lattice constants are suggested as good candidates for the selective hydrogenation of acetylene. A similar approach can be used to facilitate the future design of novel heterogeneous catalysts.

First-principles study of catalytic activity of W-doped cobalt phosphide toward the hydrogen evolution reaction

In this study,we investigated the hydrogen evolution reaction(HER)on the(101)facet of pristine and W-doped CoP using the density functional theory.Two types of Co atoms are identified on the catalyst surface:the Co atoms that present the higher d band center are marked as valid sites,whereas the others are marked as invalid sites owing to their weaker H adsorption ability.It is further revealed that W-doping can decrease the d band center of the surface Co atoms,which is beneficial for the HER;however the exposure to W weakens the desorption of H.To address the strong adsorption effect of W,the doping sites and dopant content are analyzed,and the results indicate that 8.4 wt%W doping at the invalid surface Co sites is preferred;moreover,the optimal W content increases to 16.8 wt%when W is inserted into the subsurface.The effect of W doping is weakened when the doping site is far away from the surface.

Reaction mechanism of methyl nitrite dissociation during co catalytic coupling to dimethyl oxalate:A density functional theory study

Dissociation of methyl nitrite is the first step during CO catalytic coupling to dimethyl oxalate followed by hydrogenation to ethyl glycol in a typical coal to liquid process. In this work, the first-principle calculations based on density functional theory were performed to explore the reaction mechanism for the non-catalytic dissociation of methyl nitrite in the gas phase and the catalytic dissociation of methyl nitrite on Pd(111) surface since palladium supported on alpha-alumina is the most effective catalyst for the coupling. For the non-catalytic case, the calculated results show that the CH_3O–NO bond will break with a bond energy of 1.91 eV, and the produced CH_3O radicals easily decompose to formaldehyde, while the further dissociation of formaldehyde in the gas phase is difficult due to the strong C–H bond. On the other hand, the catalytic dissociation of methyl nitrite on Pd(111) to the adsorbed CH_3O and NO takes place with a small energy barrier of 0.03 eV. The calculated activation energies along the proposed reaction pathways indicate that(i) at low coverage, a successive dehydrogenation of the adsorbed CH_3O to CO and H is favored while(ii) at high coverage, hydrogenation of CH_3O to methanol and carbonylation of CH_3O to methyl formate are more preferred. On the basis of the proposed reaction mechanism,two meaningful ways are proposed to suppress the dissociation of methyl nitrate during the CO catalytic coupling to dimethyl oxalate.

Research on C—C Bond Length Distribution in Hydrocarbon Molecules

The C--C bond dissociation energy （BDE） is a very important data in research of hydrocarbon cracking reactions, because it reflects the difficulty level of chemical reactions. But it is very difficult to obtain the C--C bond dissociation energy （BDE） by experiments, so using quantum chemistry calculation such as density functional theory （DFT） to study the C--C bond dissociation energy is a very useful means. The impact of acceptor substituents and donor substituents on the C--C bond length distribution was studied.

Non‐noble metal single‐atom catalyst with MXene support:Fe1/Ti_(2)CO_(2) for CO oxidation

MXenes have attracted considerable attention owing to their versatile and excellent physicochemi‐cal properties.Especially,they have potential applications as robust support for single atom cata‐lysts.Here,quantum chemical studies with density functional theory are carried out to systemati‐cally investigate the geometries,stability,electronic properties of oxygen functionalized Ti_(2)C(Ti_(2)CO_(2))supported single‐atom catalysts M_(1)/Ti_(2)CO_(2)(M=Fe,Co,Ni,Cu Ru,Rh,Pd,Ag Os,Ir,Pt,Au).A new non‐noble metal SAC Fe_(1)/Ti_(2)CO_(2) has been found to show excellent catalytic performance for low‐temperature CO oxidation after screening the group 8‐11 transition metals.We find that O_(2) and CO adsorption on Fe_(1) atom of Fe_(1)/Ti_(2)CO_(2) is favorable.Accordingly,five possible mechanisms for CO oxidation on this catalyst are evaluated,including Eley‐Rideal,Langmuir‐Hinshelwood,Mars-van Krevelen,Termolecular Eley‐Rideal,and Termolecular Langmuir‐Hinshelwood(TLH)mechanisms.Based on the calculated reaction energies for different pathways,Fe_(1)/Ti_(2)CO_(2) shows excellent kinet‐ics for CO oxidation via TLH mechanism,with distinct low‐energy barrier(0.20 eV)for the rate‐determining step.These results demonstrate that Fe_(1)/Ti_(2)CO_(2) MXene is highly promising 2D materials for building robust non‐noble metal catalysts.