The scientific cooperation of the Boreskov Institute of Catalysis with the catalytic communities from various countries is effected in accordance with various forms of cooperation:
According to research programs, projects and grants, the fundamentals of catalysis are studied jointly with researchers from various universities, institutions, research laboratories and companies. BIC collaborates fruitfully on a commercial basis with the leading companies from more than 20 countries, sells licenses, know-how and performs research projects according to client requests.
Academician Valentin N. Parmon is the Russian representative in the European Federation of Catalytic Societies (EFCATS), Member of the International Association of the Catalysis Societies (IACS).
Visits of the specialists from the Boreskov Institute of Catalysis to foreign institutions in 2010
|France||23||Republic of Korea||1||USA||5|
Visits of foreign specialists to the Boreskov Institute of Catalysis in 2010
|Australia||1||Indonesia||1||Republic of Korea||2|
The cooperation in the frame of the agreement between Russian Academy of Sciences (RAS) and National Council on the Scientific Research of Italy with The Istituto di Tecnologie Avanzate per l’Energia “Nicola Giordano” (CNR Institute of Advanced Energy Technologies “Nicola Giordano”), Messina – BIC, Novosibirsk on the Project “Materials with Enhanced Properties for Energy Conversion”. Coordinators: Prof. Yu. Aristov (BIC) and Prof. G. Restuccia (Istituto di Tecnologie Avanzate per l’Energia “Nicola Giordano”).
According to the agreement between RAS and CNRS BIC collaborates with the Institute de Recherches sur la Catalyse et l’Environnement de Lyon (Research Institute on Catalysis and Environment), Villeurbanne, in the frame of the Russian-French European associated Laboratory on Catalysis headed by Prof. V. Parmon and Dr. M. Lacroix. The Laboratory was established by an agreement signed December 6, 2004 in Moscow by RAS and CNRS. Four areas of research were identified:
In the frame of RAS-DST Long Term Programme of cooperation in science and technology BIC collaborates with National Chemical Laboratory, Pune. Coordinators on the Program “Catalysis” are Prof. V. Parmon and Prof. S. Sivaram.
The cooperation in the frame of the agreement between RAS and German Scientific Research Society (GSRS) with
The cooperation in the frame of Associated Research Laboratory which was established by an agreement signed December 4, 2004 by the Boreskov Institute of Catalysis and Heilongjiang University, Harbin. Chief Executive officers of Laboratory are: Prof. V. Bukhtiyarov, Prof. G. Echevsky (BIC) and Prof. Fu Hong-Gang, Prof. Wu Wei (Heilongjiang University) on the Project “Synthesis and Modification of ZSM-12 Zeolites. Zeolite ZSM-12 in Reaction of Naphthalene Alkylation with Methanol”.
COOPERATION IN THE FRAME OF PROJECTS FINANCED BY INTERNATIONAL FOUNDATIONS
Carbon Nanoreactor for Solid-State Synthesis of Novel Nanoscale Materials Based on Nanocrystalline Oxides
Prof. A. Volodin, Boreskov Institute of Catalysis, Novosibirsk, Russia
Prof. K.J. Klabunde, Kansas State University, Manhattan, Kansas, USA.
EUROPEAN COMMUNITY SIXTH FRAMEWORK PROGRAM
Co-Processing of Upgraded Bio-Liquids in Standard Refinery Units
Coordinator: Dr. Y. Solantausta, VTT Processes, Espoo, Finland
Rijksuniversiteit Groningen, The Netherlands; Boreskov Institute of Catalysis, Novosibirsk, Russia (Prof. V. Kirillov); Uhde Hochdrucktechnik GmbH, Germany; BTG Biomass Technology Group BV, The Netherlands; University of Twente, The Netherlands; STFI-PACKFORSK AG, Sweden; Institute of Wood Chemistry, Hamburg, Germany; Slovenian Institute of Chemistry, Slovenia; Arkema SA, France; Helsinki University of Technology, Finland; ALMA Consulting Group SAS, France; Centre National de la Recherche Scientifique, France; Chimar Hellas SA, Greece; Albermarle Catalysts Company BV, The Netherlands; Metabolic Explorer, France; Shell Global Solutions International, The Netherlands.
Non-Noble Catalysts for Proton Exchange Membrane Fuel Cell Anodes
Dr. G. Tsotridis, Institute for Energy, Joint Research Centre, Petten, The Netherlands
Technical University of Denmark, Lyngby, Denmark; Boreskov Institute of Catalysis, Novosibirsk, Russia (Prof. V. Parmon, Dr. O. Taran); Southampton University, United Kingdom; Technical University of Munich, Germany; Bavarian Center for Applied Energy Research; Umicore, AG & Co KG, Germany.
Demonstration of SOFC Stack Technology for Operation at 600°C
B. Rietveld, Energy Research Centre of The Netherlands, Petten, The Netherlands
University St. Andrews, UK; HTceramix, Yverdon, Switzerland; Imperial College, UK; Karlsruhe University, Germany; Oxford University, UK; University of Leoben, Austria; Boreskov Institute of Catalysis, Novosibirsk, Russia (Prof. V. Sadykov); Technical University of Denmark, Denmark; VTT Technical Research Centre of Finland, Finland; Dalian Institute of Chemical Physics, China.
EUROPEAN COMMUNITY SEVENTH FRAMEWORK PROGRAM
Reforming of Crude Glycerin in Supercritical Water to Produce Methanol for Re-Use in
Coordinator: J. Vos, BTG BiomassTechnology Group BV, The Netherlands
Acciona Servicios Urbanos, Spain; Boreskov Institute of Catalysis, Novosibirsk, Russia (Prof. V. Kirillov); Rijksuniversiteit Groningen, The Netherlands; University of Maribor, Slovenia; UHDE High Pressure Technologies GmbH, Germany; SPARQLE International BV, The Netherlands.
Engine and Turbine Combustion of Bioliquids for Combined Heat and Power Production
Coordinator: J. Vos, BTG BiomassTechnology Group BV, The Netherlands
AMO ZIL, Moscow, Russia; Aston University, Birmingham, UK; Boreskov Institute of Catalysis, Novosibirsk, Russia (Prof. V. Kirillov); BTG Biomass Technology Group BV; Central Scientific Automobile and Automotive Engines Institute, NAMI, Moscow, Russia; Encotech BV, The Netherlands; University of Florence, Florence, Italy.
Oxidative Coupling of Methane Followed by Oligomerization to Liquids
Coordinator: G. Marin, Ghent University, Belgium
Bayer Technology Service, Germany; Institute de Recherches sur la Catalyse et l’Environnement de Lyon, Villeurbanne, France; Ruhr-Universität Bochum, TECHEM, Bochum, Germany; Instituto de Technologia Quimica, Spain; Johnson Matthey, UK; SINTEF, Trondheim, Norway; Linde Engineering, Germany; Cepsa R&D Center, Spain; Haldor Topsoe, Denmark; Universitetet i Oslo, Oslo, Norway; University of Cambridge, UK; ALMA Consulting Group, France; Boreskov Institute of Catalysis, Novosibirsk, Russia (V. Sadykov); INEOS, Belgium; Institut fur Mikrotechnik Mainz Gmbh, Germany; Eni SpA, Italy.
INTERNATIONAL SCIENCE AND TECHNOLOGY CENTER (ISTC)
I.P. Glariozov*, G.M. Zhidomirov, M.I. Shilina*
(*Moscow Lomonosov State University, Moscow, Russia)
Russ. Chem. Bull., 10 (2010) pp. 1821-1830.
Density functional PBE/TZ2p quantum chemical calculations of activated complexes and pathways of model catalytic transformations of propane under the action of aluminum chloride - cobalt chloride ionic bimetallic complexes were carried out. The formation of an intermediate with a broken C-C bond can occur on the cationic cluster CoAlCl4 + characterized by the strongest coordination of propane molecule. The activation barrier to the reaction is ΔG = 25.0 kcal⋅mol−1. Activation of alkane C-H bonds follows the alkyl pathway involving the formation of bimetallic alkyl complexes. The interaction of activated hydrocarbon fragments bound to transition metal atoms in cobalt-chloroaluminate clusters can result in alkane metathesis products (in this case, ethane and a polymetallic cluster containing an extended chain alkyl radical).
ACTIVATION OF MOLECULAR OXYGEN IN TRIFLUOROACETIC ACID
M.V. Vishnetskaya*, A.V. Vasin*, V.N. Solkan**, G.M. Zhidomirov, M.Ya. Mel’nikov*** (*Gubkin Russian State University of Oil and Gas, Moscow, Russia; **Zelinsky Institute of Organic Chemistry, Moscow, Russia; ***Moscow Lomonosov State University, Moscow, Russia)
Russ. J. Phys. Chem. A, 84(11) (2010) pp. 1905-1907.
The interaction of molecular oxygen with aqueous trifluoroacetic acid (TFA) led to an increase in pH. This effect was explained by a decrease in the concentration of the protonated CF3CO2H2+ and H3O+ species after oxygen was fed in the reactor. Quantumchemical calculations show that a radical pair can be formed in an activation-free exothermal reaction involving the radical residue of the acid, the CF3CO2H2+···3O2···CF3CO2 - peroxide radical, and the acid molecule in the CF3CO2 •···HOO• collision complex. It was assumed that the activation of molecular oxygen in aqueous TFA solutions, providing the activity of the system in oxidations of various organic and inorganic substrates, is related to the formation of peroxide radicals in them.
THE MECHANISM OF FORMATION OF THE HYDROPEROXYL RADICAL IN THE CF3COOH + 3O2 SYSTEM: A QUANTUM-CHEMICAL STUDY
V.N. Solkan*, G.M. Zhidomirov, M.Ya. Mel’nikov** (*Zelinsky Institute of Organic Chemistry, Moscow, Russia; **Moscow Lomonosov State University, Moscow, Russia)
Russ. J. Phys. Chem. B, 4(5) (2010) pp. 705-708.
Ab initio quantum-chemical calculations of the (CF3CO2H2+…3O2) and (CF3CO2-…3O2) complexes were performed by the MP2 method. It was found that these complexes were characterized by low complex formation energies, of 2.97 and 1.72 kcal/mol, respectively. According to the MP2(full)/6-311++G(d, p) calculation data, the bridge stabilization of oxygen by linking with both the CF3CO2H2+ cation and CF3CO2- anion is much more favorable energetically. A study of the potential energy surface of the joint molecular system (CF3CO2H2+…3O2…CF3CO2-) shows that proton experiences activationless transfer from the cation to the 3O2 molecule accompanied by electron transfer from the CF3COO- anion. An analysis of spin density distribution shows that two radicals are stabilized in the (CF3CO2….OOH….O=C(OH)CF3) complex in the triplet state observed on the potential energy surface.
ION-EXCHANGED BINUCLEAR Ca2Ox CLUSTERS, x=1-4, AS ACTIVE SITES OF SELECTIVE OXIDATION OVER MOR AND FAU ZEOLITES
A.V. Larin*, G.M. Zhidomirov, D.N. Trubnikov*, D.P. Vercauteren** (*Moscow Lomonosov State University, Moscow, Russia; **University of Namur, Namur, Belgium)
J. Comput. Chem., 31(2) (2010) pp. 421-430.
A new series of calcium oxide clusters Ca2Ox (x = 1-4) at cationic positions of mordenite (MOR) and faujasite (FAU) is studied via the isolated cluster approach. Active oxide framework fragments are represented via 8-membered window (8R) in MOR, and two 6R and 4R windows (6R+4R) possessing one common Si-O-Si moiety in FAU. Structural similarities between the Ca2Ox (8R) and Ca2Ox (6R+4R) moieties are considered up to x = 4. High oxidation possibilities of the Ca2O2 (nR) and Ca2O3 (nR) systems are demonstrated relative to CO, whose oxidation over the Ca-exchanged zeolite forms is well studied experimentally. Relevance of the oxide cluster models with respect to trapping and desorption of singlet dioxygen is discussed.
STRUCTURE OF CHLORINE ON Ag(111): EVIDENCE OF THE (3x3) RECONSTRUCTION
B.V. Andryushechkin*, V.V. Cherkez*,**, E.V. Gladchenko****, G.M. Zhidomirov, B. Kierren**, Y. Fagot-Revurat**, D. Malterre**, K.N. Eltsov*,*** (*International Joint Laboratory IMTAS, A.M. Prokhorov General Physics Institute, Moscow, Russia; **International Joint Laboratory IMTAS, Universitй H. Poincarй–Nancy, Vandoeuvre les Nancy, France; ***Moscow Institute of Physics and Technology, Moscow Region, Russia)
Phys. Rev. B, 81 (2010) 205434 (5 pages).
The structure of the chlorine induced reconstruction of Ag(111) has been studied by a combination of low-temperature scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and density-functional theory (DFT). It was demonstrated that previously observed mysterious LEED pattern arises as a result of diffraction from a system of small Å) (15–30 triangular antiphase domains with a new (3x3) superstructure. In the author’s model supported by DFT calculations, within a (3x3) unit cell the upper silver layer reconstructs forming a couple of three-atom triangles placed in fcc and hcp sites of the substrate. Chlorine atoms occupy fourfold hollow sites between these triangles. The corner holes, which look like depressions in the STM images, are also occupied by chlorine atoms.
ON MECHANOCHEMICAL DIMERIZATION OF ANTHRACENE. DIFFERENT POSSIBLE REACTION PATHWAYS
V.M. Tapilin, N.N. Bulgakov, A.P. Chupakhin*, A.A. Politov**, A.G. Druganov*** (*Novosibirsk State University, Novosibirsk, Russia; **Institute of Solid State Chemistry and Mechanochemistry, Novosibirsk, Russia; ***Novosibirsk Institute of Organic Chemistry, Novosibirsk, Russia)
J. Struct. Chem., 51(4) (2010) pp. 635-641.
Calculations of the anthracene crystal structure, 10% isotropic compression of the anthracene crystal and its two dimers linked not through the central atoms of central rings are performed in the density functional theory approximation. Linear lattice parameters a, b, c, interatomic distances, and bond angles coincide with those determined by single crystal X-ray diffraction and previously calculated for an isolated anthracene molecule. The parameter γ is different by 12°, which is due to a weak dependence of the lattice energy on γ (the energy of only a few kcal per mole is required to turn the lattice at this angle). The calculated lattice energy (15 kcal/mol) is close to the enthalpy of sublimation. Dimers of another configuration than those linked through the central atoms of central rings are less energetically favorable. The formation of dimers at high pressure and shear deformation of “sandwiches” composed of anthracene molecules located above each other is shown, and a two-step dimerization scheme is proposed.
TO MECHANOCHEMICAL DIMERIZATION OF ANTHRACENE. CRYSTALLINE PHENANTHRENE UNDER HIGH PRESSURE AND SHEAR CONDITIONS
A.A. Politov*, A.P. Chupakhin**, V.M. Tapilin, N.N. Bulgakov, A.G. Druganov*** (*Institute of Solid State Chemistry and Mechanochemistry, Novosibirsk, Russia; **Novosibirsk State University, Novosibirsk, Russia; ***Novosibirsk Institute of Organic Chemistry, Novosibirsk, Russia)
J. Struct. Chem., 51(6) (2010) pp. 1064-1069.
Calculations at the density functional theory level show that for phenanthrene, unlike anthracene, stable dimeric structures are absent. A study of the absorption and photoluminescence spectra of crystalline phenanthrene under a pressure to 30 kbar and a simultaneous shear reveals reversible changes in the spectra: a shift of absorption bands and luminescence to the long wave region, a decrease in the intensity, and disappearance of the vibrational structure. Unlike anthracene, the dimerization (and other irreversible transformations) of phenanthrene under the simultaneous effect of high pressure and shear is not observed.
ELECTRONIC STRUCTURES OF MIXED IONIC-ELECTRONIC CONDUCTORS SrCoOx
V.M. Tapilin, A.R. Cholach, N.N. Bulgakov
J. Phys. Chem. Solids, 71(11) (2010) pp. 1581-1586.
Electronic structures of SrCoOx with x=3, 2.875 and 2.75 were calculated by DFT technique in SLDA approximation. Two kinds of oxygen vacancy ordering with energies of 0.22 and 0.01 eV lower in comparison with random vacancy distribution were
revealed. The transition between these ordered vacancy systems with the activation energy 0.34 eV can be a step in the ionic conductivity mechanism. The calculated ion charges, magnetic moments and electron density of states were used to analyze chemical bonding in the crystals. All calculated compounds have metal electronic conductivity.
WATER EFFECT ON THE ELECTRONIC STRUCTURE OF ACTIVE SITES OF SUPPORTED VANADIUM OXIDE CATALYST VOx/TiO2(001)
V.I. Avdeev, V.M. Tapilin
J. Phys. Chem. C, 114(8) (2010) pp. 3609-3613.
The interaction of water molecules with the reduced and fully oxidized surface sites of the supported vanadium oxide catalyst VOx/TiO2 has been investigated by the Periodic DFT method. It has been found that the molecular structures of the surface VOx species are radically altered when adsorbed water is involved in the redox cycle. Water dissociates spontaneously on the reduced vanadium sites forming the surface hydroxyl groups OH. The following reoxidation by gas-phase oxygen results in the formation of active sites O=VO2(OH) including both the Bronsted acid sites OH and the vanadyl oxygen V=O more reactive than on the dehydrated surface. Gas-phase oxygen, embedded on the surface under oxidation, does not take part in the formation of surface hydroxyl groups. The hydroxylation-hydration reaction path on the fully oxidized VOx/TiO2 surface has been calculated. It has been found that the recombination reaction of the two surface hydroxyl groups V-OH to form water with the following water desorption prevails over the reverse reaction of hydroxylation. In agreement with the experimental data it was concluded that lattice oxygen of surface vanadia species VOx, rather than gas-phase oxygen, undergoes isotope exchange with that of the adsorbed water.
SPIN-POLARIZED SELF-CONSISTENT-FIELD EQUATIONS FOR PAIRED ORBITALS
I.L. Zilberberg, S.F. Ruzankin
Phys. Rev. A, 82(4) (2010) 042505.
Unrestricted Hartree-Fock-like equations are proposed to find multiple spin-symmetry-broken states of the molecular systems. Developed equations are pseudo-eigenvalue-type equations for the Fock-type operators constructed in such a way to
include an effective field which makes different-spin orbitals biorthogonal. The eigenvectors of these operators are noncanonical Hartree-Fock orbitals becoming Lowdin-Amos-Hall paired (corresponding) orbitals after self-consistency is achieved. The eigenvalues of the modified Fock operators appear to be the energies of the paired orbitals. Because the paired orbitals do not follow the spatial symmetry of the molecular nuclear core, the equations allow one to obtain the broken symmetry states with relative ease as demonstrated for the model H6 hexagon molecule. For this molecule, the Čнћek-Paldus instability matrix analysis predicts the existence of three spin-symmetry-broken states. All these solutions are systematically achieved by the paired equations, unlike the standard unrestricted equations which basically converge to a single solution. The proposed approach is also valid for the density functional theory in which the spin-polarized Kohn-Sham equations might be transformed to paired equations.
PAIRED ORBITALS FOR DIFFERENT SPINS EQUATIONS
I.L. Zilberberg, S.F. Ruzankin
J. Comput. Chem., 31(1) (2010) pp. 84-89.
Eigenvalue-type equations for Lowdin-Amos-Hall spin-paired (corresponding) orbitals are developed to provide an alternative to the standard spin-polarized Hartree-Fock or Kohn-Sham equations in dealing with broken-symmetry (BS) states. To derive paired orbitals for different spins (PODS) equations there has been applied Adams-Gilbert “localizing” operator approach. The PODS equations contain different operators for different spins the eigen-vectors of which are paired orbitals associated with the same eigenvalue for each pair. Preliminary applications to simple systems show viability of this approach. Although the spectrum of possible applications of the PODS equations seems to be quite wide, they would be especially useful for obtaining and analyzing the S-z = 0 BS solutions for the systems with antiferromagnetic structure.
ADSORPTION SPECIES OF ETHYL BENZOATE IN MgCl2-SUPPORTED ZIEGLER-NATTA CATALYSTS. A DENSITY FUNCTIONAL THEORY STUDY
D.V. Stukalov, V.A. Zakharov, I.L. Zilberberg
J. Phys. Chem. C, 114(1) (2010) pp. 429-435.
Adsorption species of ethyl benzoate (EB) on the (104) and (110) MgCl2 surfaces have been studied within DFT. As a result, monodentate and bidentate complexes of EB were obtained on both the MgCl2 surfaces. The bidentate structures on the (104) MgCl2 surface proved to be stabilized by the decreased distance between neighboring adsorption sites (surface Mg cations). The different affinity of EB for the five-and four-coordinated Mg cations predicted was suggested to be the cause of changing the equilibrium shape of MgCl2 crystals upon growing in the presence of EB: EB chemisorption seems to stabilize the (110) MgCl2 surface to a greater degree as compared to the (104) MgCl2 surface. The influence of EB coordination mode on active site stereoselectivity is discussed.
KOOPMANS'S THEOREM IN THE RESTRICTED OPEN-SHELL HARTREE-FOCK METHOD: II. THE SECOND CANONICAL SET FOR ORBITALS AND ORBITAL ENERGIES
E.R. Davidson*, B.N. Plakhutin (*University of Washington, Seattle, Washington, USA)
J. Chem. Phys., 132(18) (2010) 184110.
A treatment of the validity of Koopmans’s theorem (KT) in the restricted open-shell Hartree– Fock (ROHF) method can be separated into two essentially different cases. The first of them involves the one-electron processes X→Xj± in which the spin state of an ion Xj± having a hole or an extra electron in the closed, open or virtual orbital ϕj is correctly described by a one-determinant wave function. This case was analyzed using different methods by Plakhutin et al. [J. Chem. Phys. 125, 204110 (2006)] and by Plakhutin and Davidson [J. Phys. Chem. A 113, 12386 (2009)]. In the present work the authors analyze more complex processes where the state of an ion cannot be described by a single determinant. An example of such processes is the removal of an alpha electron from the closed shell of a high-spin half-filled open-shell system X. For this case it is given a slightly generalized formulation of KT in both the “frozen” orbital approximation (i.e., within the canonical ROHF method) and the limited configuration
interaction approach for ionized systems. The authors also show that a simultaneous treatment of KT for all one-electron ionization processes possibly leads to the necessity of introducing in the canonical ROHF method two different sets of orbitals and two respective sets of orbital energies. The theory developed is compared with the previous formulations of KT in the restricted (ROHF) and unrestricted Hartree-Fock methods, and in the unrestricted density functional theory. The practical applicability of the theory is verified by comparing the KT estimates of the vertical ionization potentials in molecules O2 and NO2 with the respective experimental data.
C60 FULLERENE AS A PSEUDOATOM OF THE ICOSAHEDRAL SYMMETRY
A.V. Nikolaev*, B.N. Plakhutin (*Frumkin Institute of Physical Chemistry and Electrochemistry, Moscow, Russia)
Russ. Chem. Rev., 79(9) (2010) pp. 729-755.
Unique features of the electronic structure and spectra of the C60 (Ih) fullerene and its ions related to the icosahedral symmetry are discussed. The so-called ′accidental′ degeneracy of terms in the open electron shells gN and hN (corresponding to four- and fivefold degeneracy of molecular orbitals, respectively) and the abnormal (′non-Bethe′) splitting of terms in the hN configuration are considered. The need to describe these terms arises in studies of ionized and excited states of the C60 molecule and its derivatives. A novel approach to the description of C60m± ions based on representation of the C60 (Ih) fullerene as a (pseudo)atom of icosahedral symmetry is considered in detail. The approach involves an expansion of the molecular orbitals of C60 in terms of the atomic orbitals centred at the origin (at the centre of the C60 molecule) and a multipole expansion of the electron repulsion. The energy spectra of the fullerene and C60m± ions, the magnetic moments and optical dipole transitions are considered. The results obtained are compared with those of ab initio calculations and with the available experimental data.
STABILIZATION OF Au AT EDGES OF BIMETALLIC PdAu NANOCRYSTALLITES
I.V. Yudanov, K.M. Neyman* (*University of Barcelona, Barcelona, Spain)
Phys. Chem. Chem. Phys., 12(19) (2010) pp. 5094-5100.
Density functional calculations were performed to study the distribution of Au atoms in bimetallic PdAu
nanoparticles. A series of Pd79–nAun clusters of truncated octahedral shape with different content of Au ranging from n = 1 to 60 was used to model such bimetallic nanosystems. Segregation of Au to the particle surface is found to be thermodynamically favorable. The most stable sites for Au substitution are located at the edges of the PdAu nanoclusters. The stabilization at the edges is rationalized by their higher flexibility for surface relaxation which minimizes the strain induced by larger atomic radius of Au as compared to Pd. This stabilization of Au at the edges indicates the possibility to synthesize PdAu particles with Pd atoms located mainly on the facets, and edges “decorated” by Au atoms. Such nanocrystallites are expected to exhibit peculiar catalytic properties and, being thermodynamically stable, should be prone to retaining their initial shape under catalytic conditions.
SIMULATION OF HETEROGENEOUS CATALYSTS AND CATALYTIC PROCESSES USING THE DENSITY FUNCTIONAL METHOD
V.A. Nasluzov*, E.A. Ivanova-Shor*, A.M. Shor*, I.V. Yudanov, N. Rцsch** (*Institute of Chemistry and Chemical Technology, Krasnoyarsk, Russia; **Technical University of Munich, Garching, Germany)
Kinet. Catal., 51(6) (2010) pp. 832-842.
The review is devoted to the use of high-level quantum-chemical calculations by the density functional method for the simulation of heterogeneous catalytic systems based on transition metals. The following problems are considered:
(1) the development of methods for simulating metal particles supported on the surfaces of ionic and covalent oxides; (2) the calculation of the properties of individual transition metal atoms and small clusters adsorbed on the surfaces of MgO, α-Al2O3, γ-Al2O3, and various modifications of SiO2 and in the pores of zeolites; (3) the mechanisms of hydrogen activation and acrolein hydrogenation on the metallic and partially oxidized surface of silver; and (4) the mechanism of formation of carbon residues upon the decomposition of methanol on nanosized Pd particles.
SMALL GOLD SPECIES SUPPORTED ON ALUMINA. A COMPUTATIONAL STUDY OF a-Al2O3(0001) AND y-Al2O3(001) USING AN EMBEDDED-CLUSTER APPROACH
V.A. Nasluzov*,**, T.V. Shulimovich*, A.M. Shor*, V.I. Bukhtiyarov, N. Rцsch***
(*Institute of Chemistry and Chemical Technology, Krasnoyarsk, Russia; **Siberian Federal University, Krasnoyarsk, Russia; ***Technical University of Munich, Garching, Germany)
Phys. Status Solidi B, 247(5) (2010) pp. 1023-1031.
The authors calculated the structures of and analyzed the bonding in adsorption complexes of small gold species Aun on a-Al2O3(0001), n = 1-6, and y-Al2O3(001), n = 1-5. A scalar-relativistic gradient-corrected density functional (DF) method was applied to cluster models of the support that were embedded in an extended elastic polarizable environment (EPE). The shortest Au—O distances, 204-211 pm, are consistent with extended X-ray adsorption fine structure (EXAFS) data for gold clusters on alumina surfaces. The calculated total adsorption energies increase with cluster nuclearity, up to n = 4, but drop for larger adsorbed species. In the gas phase, these small gold clusters exhibit a planar structure which they keep, oriented parallel to the surface, as adsorbates on a-Al2O3(0001). Unfavorable energy contributions result for larger clusters as their planar shape is notably distorted by the interaction with the support which amounts to 0.5-1.5 eV. On у-Al2O3(001), also the larger gold clusters retain their intrinsic planar structure as they adsorb oriented perpendicular to the surface. The corresponding adsorption energies are slightly smaller, 0.3-1.2 eV.
ON QUANTITATIVE DESCRIPTION OF METAL PARTICLES SIZE EFFECT IN CATALYTIC KINETICS
D.Yu. Murzin*, I.L. Simakova (*Еbo Akademi University, Turku/Еbo, Finland)
Kinet. Catal., 51(6) (2010) pp. 828-831.
Quantitative description for turnover frequency dependence on the metal cluster size for a two-step catalytic cycle was performed based on a thermodynamic approach, which accounts for changes of the chemical potential upon adsorption depending on the metal cluster size. Such analysis revealed a possibility for turnover frequency to exhibit a maximum. A very good
correspondence between calculated and experimental data in hydrogenation and decarboxylation reactions over palladium was achieved.
ELECTRONIC AND GEOMETRIC STRUCTURE OF ISOMERS OF NITRIC ACID. DFT QUANTUM CHEMICAL CALCULATIONS
I.I. Zakharov, O.I. Zakharova*, A.B. Tselishchev*, M.G. Loriya* (*V. Dal’ East Ukrainian National University, Severodonetsk, Ukraine)
J. Struct. Chem., 50(5) (2009) pp. 805-813.
Based on the B3LYP/6-311++G(3df,3pd) density functional method, quantum chemical calculations of the electronic structure, geometry, and thermodynamic parameters of eight isomers of nitric acid (three known isomers in the form of peroxynitrous acid ONOOH and five new isomers in the form of oxo-conformation OON(H)O) are presented in the work. The molecular structure of each isomer is characterized by a local minimum on the potential energy hypersurface of the HNO3 molecular system and corresponds to one of its stationary states. A theoretical study of the reactivity of nitric acid oxo-isomers characterized for the first time can provide adequate explanation for experiments on the autocatalytic use of nitric acid vapors in binding molecular nitrogen. The results obtained can be a direction for developing principally new methods to bind atmospheric nitrogen and activate methane, which are fundamental problems in chemical science and technology.
parameters of eight isomers of nitric acid (three known isomers in the form of peroxynitrous acid ONOOH and five new isomers in the form of oxo-conformation OON(H)O) are presented in the work. The molecular structure of each isomer is characterized by a local minimum on the potential energy hypersurface of the HNO3 molecular system and corresponds to one of its stationary states. A theoretical study of the reactivity of nitric acid oxo-isomers characterized for the first time can provide adequate explanation for experiments on the autocatalytic use of nitric acid vapors in binding molecular nitrogen. The results obtained can be a direction for developing principally new methods to bind atmospheric nitrogen and activate methane, which are fundamental problems in chemical science and technology.