23 ноября 2023
Памяти Р.А. Буянова
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: conducting joint seminars on catalysis, exchanging the information and appropriate materials, exchanging research fellows, visiting scientific centers, and participating in congresses and symposia on theoretical and applied catalysis.
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 2009
Austria |
1 |
Finland |
3 |
Netherlands |
11 |
Azerbaijan |
1 |
France |
29 |
Saudi Arabia |
4 |
Belarus |
6 |
Germany |
38 |
Singapore |
1 |
Belgium |
3 |
Greece |
5 |
Spain |
10 |
Brazil |
4 |
Italy |
23 |
Sweden |
2 |
Bulgaria |
2 |
Japan |
3 |
Turkey |
1 |
Canada |
1 |
Kazakhstan |
2 |
Ukraine |
5 |
China |
13 |
Korea |
2 |
United Kingdom |
2 |
Cyprus |
2 |
Mexico |
3 |
USA |
8 |
Denmark |
3 |
Poland |
8 |
Venezuela |
1 |
India |
6 |
|
|
|
|
Visits of foreign specialists to the Boreskov Institute of Catalysis in 2009
Australia |
1 |
Israel |
1 |
Republic of Korea |
6 |
Belgium |
1 |
Italy |
5 |
Saudi Arabia |
1 |
Bulgaria |
2 |
Japan |
2 |
Slovenia |
1 |
China |
12 |
Jordan |
1 |
Switzerland |
2 |
Croatia |
1 |
Kazakhstan |
1 |
Syria |
1 |
Denmark |
7 |
Lebanon |
1 |
Tunisia |
1 |
Finland |
2 |
Morocco |
2 |
Turkey |
1 |
France |
9 |
Netherlands |
10 |
United Kingdom |
2 |
Germany |
16 |
Pakistan |
1 |
USA |
7 |
India |
12 |
Poland |
16 |
|
|
ITALY
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”).
FRANCE
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), Lyon in the frame of the Russian-French European associated Laboratory on Catalysis headed by Acad. 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:
INDIA
In the frame of Indo-Russian Integrated Long Term Programme of cooperation in science and technology (ILTP) BIC collaborates with National Chemical Laboratory, Pune on the Project “Design of Bifunctional Supported Non-Iron Catalysts for Low Temperature Ammonia Synthesis”. Coordinators: Dr. B. Moroz (BIC) and Dr. S.B. Halligudi (National Chemical Laboratory).
Coordinators on the Program “Catalysis” are Prof. V. Parmon and Dr. S. Sivaram.
SWEDEN
Cooperation with Chalmers University of Technology, Göteborg on the Project “Modeling of Hydrogen Adsorption by Metal Nanoparticles”. Coordinators: Prof. V. Zhdanov (BIC) and Prof. B. Kasemo (Chalmers University of Technology).
GERMANY
The cooperation in the frame of the agreement between RAS and German Scientific Research Society (GSRS) with
- Ruhr-Universität Bochum
, Bochum on the Project “Synthesis and Reactivity of Novel Heterogeneous Polyoxometallate Based Catalysts for Alcohol Oxidation Containing Gold and TiO2”. Coordinators: Prof. O. Kholdeeva (BIC) and Prof. Klaus Merz (Ruhr-Universität Bochum)- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin on the Project “Development of in situ Methods for Study of Solid Surfaces”. Coordinators: Prof. V. Bukhtiyarov (BIC) and Prof. R. Sсhlögl (Fritz-Haber-Institut der MPG)
- Universität Konstanz, Konstanz on the Project “Various Resting States of the Catalysts for Olefin Polymerization and Oligomerization – Studying of the Reaction Route by Methods of Optical, ESR and NMR Spectroscopy”. Coordinators: Prof. E. Talsi (BIC) and Prof. H. Brintzinger (Universität Konstanz).
THE NETERLANDS
Cooperation with University of Technology, Eindhoven on the Project “Preparation of Mesoporous Titania Films on the Support”. Coordinators: Prof Z. Ismagilov (BIC) and Prof. J.C. Schouten (University of Technology).
JAPAN
Bilateral agreement BIC - Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, on the Project “Adsorption and Chemical Reactions for Heat Transformation”. Coordinators: Prof. Yu. Aristov (BIC), Prof. Y. Kato (Research Laboratory for Nuclear Reactors).
CHINA
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
INTAS - SB RAS Supported Project
Electromagnetic Response Properties of Carbon Onions and Carbon Onion-Based Composites
Project Coordinator:
Dr. Ph. Lambin, Facultes Universitaires Notre-Dame de la Paix, Namur, Belgium
Participants:
Belarus State University, Minsk, Belarus; University of Joensuu, Finland; Institute for Technical Physics and Materials Science, Budapest, Hungary; The Boreskov Institute of Catalysis, Novosibirsk, Russia (Dr. V. Kuznetsov), Nikolaev Institute of Inorganic Chemistry, Novosibirsk, Russia.
CRDF Project
Carbon Nanoreactor for Solid-State Synthesis of Novel Nanoscale Materials Based on Nanocrystalline Oxides
Project Coordinators:
Prof. A. Volodin, The Boreskov Institute of Catalysis, Novosibirsk, Russia
Prof. K.J. Klabunde, Kansas State University, Manhattan, Kansas, USA.
EUROPEAN COMMUNITY SIXTH FRAMEWORK PROGRAM
I. International Partnership for a Hydrogen Economy for Generation of New Ionomer Membranes
Coordinator: Dr. R. Mallant, Energy Research Centre of The Netherlands, Petten, The Netherlands
Partners:
Daimler Chrysler; FuMA-Tech GmbH; CNRS Montpellier; Dohgyue Chenzhou New Materials Company; Shanghai Jiao Tong University, Shanghai, China; The Boreskov Institute of Catalysis, Novosibirsk, Russia (Prof. V. Bukhtiyarov).
II. Co-Processing of Upgraded Bio-Liquids in Standard Refinery Units
Coordinator: Dr. Y. Solantausta, VTT Processes, Espoo, Finland
Partners:
Rijksuniversiteit Groningen, The Netherlands; The 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.
III. Non-Noble Catalysts for Proton Exchange Membrane Fuel Cell Anodes
Coordinator:
Dr. G. Tsotridis, Institute for Energy, Joint Research Centre, Petten, The Netherlands
Partners:
Technical University of Denmark, Lyngby, Denmark; The Boreskov Institute of Catalysis, Novosibirsk, Russia (Acad. 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.
IV. Novel Materials for Silicate-Based Fuel Cells
Coordinator: Dr. Ch. Arguirusis, Technische Universität Clausthal, Clausthal, Germany
Partners:
University of Aveiro, Aveiro, Portugal; Foundation of Research and Technology Hellas, Greece; Katholieke University of Leuven, Belgium; Max-Plank Institute of Colloids and Interfaces, Munchen, Germany; The Boreskov Institute of Catalysis, Novosibirsk, Russia (Prof. V. Sadykov); Ceramics and Refractories Technological Development Company, Greece; Ceramiques Techniques et Industrielles, France.
EUROPEAN COMMUNITY SEVENTH FRAMEWORK PROGRAM
I. Reforming of Crude Glycerin in Supercritical Water to Produce Methanol for Re-Use in Biodiesel Plants
Coordinator: J. Vos, BTG BiomassTechnology Group BV, The Netherlands
Partners:
Acciona Servicios Urbanos, Spain; The 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.
II. Engine and Turbine Combustion of Bioliquids for Combined Heat and Power Production
Coordinator: J. Vos, BTG BiomassTechnology Group BV, The Netherlands
Partners:
AMO ZIL, Moscow, Russia; Aston University, Birmingham, UK; The 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.
III. Oxidative Coupling of Methane Followed by Oligomerization to Liquids
Coordinator: G. Marin, Ghent University, Belgium
Partners:
Bayer Technology Service, Germany; Institute de Recherches sur la Catalyse et l’Environment, Lyon, 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; The Boreskov Institute of Catalysis, Novosibirsk, Russia (V.A. Sadykov); INEOS, Belgium; Institut fur Mikrotechnik Mainz Gmbh, Germany; Eni SpA, Italy.
NATO PROGRAMME: SCIENCE FOR PEACE AND SECURITY
Capture and Decontamination of Chemical & Biological Agents by Novel Catalysts and
Millisecond Jet Reactors
Project Coordinator from a NATO Country:
Prof. P. Smirniotis, University of Cincinnaty, Cincinnaty, United States
Project Coordinator from a Partner Country:
Prof. A. Vorontsov, The Boreskov Institute of Catalysis, Novosibirsk, Russia.
INTERNATIONAL SCIENCE AND TECHNOLOGY CENTER (ISTC)
I. Small Capacity Fuel Cells
Project Manager from BIC Prof. V. Kirillov.
II. Environmentally Friendly Small Capacity Power Plants Based on Fuel Cells for Stationary Application
Project Manager from BIC Prof. V. Kirillov.
III. Development of High-Performance Oxygen-Containing Membranes and Compact
Syn-Gas Generators on Their Base
Project Manager from BIC Prof. V. Sadykov.
IV. Synthesis and Investigation of the Metal Oxide Catalysts for Photocatalytic Degradation of Harmful Gases Resulted from Terrorist Acts and Man-Caused Catastrophes
Project Manager from BIC Prof. A. Vorontsov.
V. Catalytic Production of SO3 for Conditioning of Electrostatic Precipitators Using in Russia and the Newly Independent States (NIS)
Project Manager from BIC Prof. A. Zagoruiko.
VI. Development of an Integrated Separator for Direct Reforming of Hydrocarbons in High-Temperature Fuel Cells
Project Manager from BIC Prof. Z. Ismagilov.
VII. Synthesis, Formation and Modification of Organic Nanoparticles in Supercritical Fundamentals and Applications
Project Manager from BIC Prof. V. Anikeev.
VIII. Composite Nanocarbon Based Materials for Electromagnetic Applications
Project Manager from BIC Dr. V. Kuznetsov.
CONFERENCE AND EXHIBITION ACTIVITIES
The advertising and information activities are universal marketing tools for establishing professional contacts. Again, this is a necessary part of the market examination to be settled in the world. Each year, achievements of the Boreskov Institute of Catalysis are demonstrated at the very prestigious exhibitions in Russia and abroad. The goal is to strengthen collaboration with the present partners and to attract attention of potential customers.
In 2009, the most important BIC’s achievements in the area of applied catalysis were
presented at the Exhibitions:
Golden Medal and Diploma for “Vehicle Syngas Generator”
Big Golden Medal and Diploma ITE for “Fiber-Glass Based Catalysts – New Type of Catalytic Systems”.
Solution of many specific problems requires joint efforts in order to promote its fastest accomplishing. International congresses, symposia, conferences, and seminars are the most productive to familiarize scientists with innovations outside their own research and to disseminate the information about the results achieved to a wider audience. One of the directions of the scientific-organizational work carried out in the Institute is aimed on conducting conferences and seminars with the participation not only of Russian scientists and researchers from NIS, but foreign participants as well.
Страницы 1 - 1 из 16
Начало | Пред. | 1 2 3 4 5 | След. | Конец | Все
METHANOL CATALYTIC OXIDATION
I.V. Malakhova, A.A. Shubin
Kinet. Catal., 50(4) (2009) pp. 583-586.
The quantum-chemical calculations of the hydroxymethyl radical •CH2OH were performed for the first time and a theoretical EPR spectrum of this radical was constructed. The formation of the hydroxymethyl radical in the reaction of methanol oxidation is thermodynamically favourable. The shape and parameters of the constructed spectrum differed from those for radicals experimentally detected in the catalytic oxidation of methanol using the matrix isolation method. However, they are consistent with the spectrum ascribed to the EPR spectrum of •CH2OH observed in the direct photolysis of methanol. This result allows one to refine the identification of the nature of radicals formed in the catalytic reaction of methanol oxidation.
NITROSONIUM NITRITE ISOMER OF N2O3: QUANTUM-CHEMICAL DATA
I.I. Zakharov*,**, O.I. Zakharova**
(*The Boreskov Institute of Catalysis, Novosibirsk , Russia;
**Severodonetsk Technological Institute, V. Dal West Ukrainian National University, Severodonetsk, Ukraine)
J. Struct. Chem., 50(2) (2009) pp. 212-218.
The geometrical, electronic, and thermodynamic parameters of three known isomers of dinitrogen trioxide N2O3 were calculated by the density functional theory DFT/B3LYP method using the 6-311++G(3df) basis. The structure of the new isomer, NONO2, was calculated. From the calculation of vibrational frequencies it follows that the structure of NONO2 has a local potential energy minimum and corresponds to the stationary state of the N2O3 isomer. The molecular structure of NONO2 is characterized by a substantial negative charge on the NO2 fragment and positive charge on the NO fragment. The electronic structure of the NO+NO2- isomer can be characterized as nitrosonium nitrite, which can be oxidized to nitrite and participate in nitrosylation in accordance with the biogenic characteristics of the NOx intermediate, assumed to be formed in biological systems during the oxidation of NO.
EFFECT OF MASS TRANSFER ON THE REACTION RATE IN A MONOLITHIC CATALYST WITH POROUS WALLS
O.P. Klenov, S.A. Pokrovskaya, N.A. Chumakova, S.N. Pavlova, V.A. Sadykov, A.S. Noskov
Catal. Today, 144(3-4) (2009) pp. 258-264.
The influence of reacting gas flow on the heterogeneous reaction in catalyst volume of honeycomb porous monolith with triangular channels was studied. The spatial distributions
of the reacting gas flow, the rates of local mass transfer between channel walls and gas flow, as well as the interaction of transfer processes and a catalytic reaction were determined
on the basis of the computational fluid dynamics. The reactions of deep oxidation and steam reforming of methane were considered as model reactions.
It was shown that there is no stabilization of the reacting flow over the whole channel length under studied conditions. The most intensive changing of the gas streams appears near the channel inlet, which causes the highest local rates of interphase exchange processes, the rate difference is up to two orders of magnitude. A higher reaction rate exists in the initial part due to penetration of feed components into the catalyst volume through the frontal surface. This leads to increasing the effectiveness factor whose value is above unity near the channel inlet. The reaction rate limitation by the transport of reagents inside porous wall was observed along the monolith length.
OXIDATION OF FORMALDEHYDE TO FORMIC ACID OVER V2O5/TiO2 CATALYSTS: A DFT ANALYSIS OF THE MOLECULAR REACTION MECHANISMS
V.I. Avdeev, V.N. Parmon
J. Phys. Chem.,
113(7) (2009) pp. 2873-2880.
Oxidation of formaldehyde to formic acid on the surface of titania-supported vanadia is studied with density functional theory (DFT) and a dioxo-vanadyl (O=V-O-V=O) catalyst model. Two probable mechanisms (a redox Mars-van Krevelen mechanism and an associative mechanism) are considered and transition states and intermediates along these reaction pathways are investigated. The key intermediate of the redox mechanism is a dioxymethylene complex. Its successive transformation leads to a stable surface formate complex. The subsequent transformation of formate to formic acid can occur only in the presence of dioxygen. The key intermediate of the associative mechanism is a peroxo-oxo-methylene complex. Its successive transformation leads to the adsorbed formic acid. On the basis of the calculated activation barriers, the associative mechanism appears to be more probable.
ELECTRONIC STRUCTURE AND STABILITY OF PEROXIDE DIVANADATE SPECIES V(O−O) ON THE TiO2(001)
V.I. Avdeev, V.M. Tapilin
J. Phys. Chem. C, 113(33) (2009) pp. 14941-14945.
Electronic structure and stability of the VOx species forming on the anatase-TiO2(001)-(4×1) reconstructed surface at redox cycle V5+ −O−V5+ ↔ V4+ −O−V4 have been investigated on the basis of periodic density functional theory calculations. It is shown that oxidizing of the key intermediate of Mars−van Krevelen mechanism [O−V4+−O−V4+] by the gas phase dioxygen leads to the substantial structure relaxation of the surface VOx species within a monolayer. As a result, the binding energy of the vanadyl bond V═O decreased and the stable peroxide complex V(O−O) can be formed on the fully oxidized VOx/TiO2 surfaces. This complex manifests itself as a peak near Fermi level (−0.23 eV) in the total density of states (DOS) and O-projected density of states (PDOS).
QUANTUM CHEMICAL CALCULATION OF THE CATALYTIC REACTION OF ETHANE DEHYDROGENATION ON GALLIUM OXIDE- HYDROXIDE BINUCLEAR CLUSTERS IN OXIDIZED GaO/ZSM-5 ZEOLITE
I.V. Kuz’min*, G.M. Zhidomirov, V.N. Solkan*, V.B. Kazanskii*
(*Zelinsky Institute of Organic Chemistry, Moscow, Russia)
Kinet. Catal., 50(5) (2009) pp. 752-759.
The catalytic activity of oxidized GaO/HZSM-5 in the reaction of alkane dehydrogenation can be due to hydrogenated gallium oxide clusters stabilized in the cationic positions of the zeolite. The binuclear gallium oxide clusters [Ga2O2]2+ in oxidized gallium- substituted high-silica zeolite HZSM-5, which are isomeric to two gallyl ions [GaO]+ stabilized on two spatially separated lattice aluminum ions, were considered using the DFT method within the framework of a cluster approach. It was found that, even in the case of a relatively large distance between these aluminum ions, gallium oxide particles in oxidized GaO/HZSM-5 can occur as charged planar [Ga2O2]2+ four-membered rings. These cluster particles exhibited a high affinity to hydrogen, and they were readily hydrogenated with the retention of their structural integrity. It was demonstrated that this partially hydrogenated cluster could be responsible for the catalytic process of ethane dehydrogenation. In the first step, ethane dissociatively added to the [Ga2O2H2]2+ cluster. Then, the ethylene molecule was eliminated from the resulting intermediate to leave the [Ga2O2H4] 2+ cluster. The cycle was closed by the elimination of a hydrogen molecule with the formation of the initial structure of [Ga2O2H2] 2+.
ON THE STABILITY OF COPPER(II) ORGANIC COMPOUNDS WITH THE σ BOND Cu-C: A QUANTUM-CHEMICAL STUDY
E.N. Golubeva*, G.M. Zhidomirov, A.I. Kokorin**
(*Moscow Lomonosov State University, Moscow, Russia; **Semenov Institute of Chemical Physics, Moscow, Russia)
Doklady Chem., 426(2) (2009) pp. 143-145.
In this paper, the results of quantum chemical calculations of the structure and properties of copper(II) organic compounds are reported with the aim to demonstrate the possibility of their existence by the example of ClnCu(II)R1–n, where R is C and C3, and determine their geometric parameters and the Cu–C bond energy. In addition, it was important to calculate the energies of possible mono- and bimolecular reactions involving ClnCu(II)R1–n and justify the most probable mechanism of ClnCu(II)R1–n transformations.
DFT ANALYSIS OF PROPANE CYCLIZATION OVER BINUCLEAR Ga-CLUSTERS IN MORDENITE
A.V. Larin*, G.M. Zhidomirov, D.N. Trubnikov*, D.P. Vercauteren**
(*Moscow Lomonosov State University, Moscow, Russia; **University of Namur, Namur, Belgium)
J. Mol. Catal. A: Chem., 305(1-2) (2009) pp. 90-94.
Molecular and dissociative adsorption of propane on binuclear (Ga2O2)2+ cluster located at the cation positions of Ga-exchanged mordenite zeolite are modelled using DFT calculations via the isolated cluster approach. Relative energies of the dissociative intermediates show the most stable bidentate complexes, i.e., via both primary C atoms of propane to both Ga atoms. This structure really is the suitable precursor of cyclo-propane formation. The hypothesis of cyclo-propane intermediate was proposed by Derouane et al. to explain the 13C/12C exchange migration within propane molecules in Ga-exchanged zeolites.
ION-EXCHANGED BINUCLEAR CLUSTERS AS ACTIVE SITES OF SELECTIVE OXIDATION OVER ZEOLITES
G.M. Zhidomirov, A.V. Larin*, D.N. Trubnikov*, D.P. Vercauteren**
(*Moscow Lomonosov State University, Moscow, Russia; **University of Namur, Namur, Belgium)
J. Phys. Chem., C, 113(19) (2009) pp. 8258-8265.
A new catalytic oxidation cycle over binuclear Zn- and Ca-cation clusters in zeolites is proposed. Intermediate active clusters appear due to trapping of dioxygen. CO oxidation is considered as a model reaction over a cluster located in an 8-membered (8R) ring. Geometries of active clusters involved in the catalytic cycle vary depending on the nature and size of the cation. Reagents, transition states, and products have been optimized at the isolated cluster level considering DFT functionals (B3LYP, B3P86, and B3PW91) with the 6-31G* or 6-311++G** basis sets. Moderate activation energies of 23.0 and 35.7 kcal/mol at the B3LYP/6-31G* level are obtained for CO oxidation over Zn- and Ca-clusters, respectively.
GENERATION OF O― RADICAL ANIONS ON MgO SURFACE: LONG-DISTANCE CHARGE SEPARATION OR HOMOLYTIC DISSOCIATION OF CHEMISORBED WATER?
S.E. Malykhin, A.M. Volodin, A.F. Bedilo, G.M. Zhidomirov
J. Phys. Chem., C, 113(24) (2009) pp. 10350-10353.
O― radical anions were observed over a partially hydroxylated MgO surface after illumination by monochromatic light with λ = 280 and 303 nm. As all comer oxygen atoms are covered with adsorbed hydroxyl groups after activation at 450°C, this process is initiated by selective excitation of 3-coordinated complexes [Mg2+ ―O―]3C containing chemisorbed water. A new mechanism for generation of the O― radical anions is suggested. It is based on homolytic dissociation of chemisorbed water followed by migration of a hydrogen atom, probably, to a different nanoparticle rather than on long-distance separation of charges. The surface structure remaining after its detachment consists of an •OH radical stabilized near the corner oxygen atom. The imminent charge transfer generates a hole at the corner oxygen atom stabilized by a hydroxyl group [OH―···Mg2+ ―O―]3C. DFT simulation of this structure showed that it reproduces the main characteristics of the radical anions O―3C. The overall structure is electrically neutral. The charge of the hole is compensated by the nearby hydroxyl group. So, no long-distance charge separation is required.
INTERACTION OF A SINGLE WATER MOLECULE WITH A SINGLE GRAPHITE LAYER: AN INTEGRATED ONIOM STUDY
N.U. Zhanpeisov, G.M. Zhidomirov, H. Fukumura* (*Tohoku University, Japan)
J. Phys. Chem., C, 113(15) (2009) pp. 6118-6123.
Integrated ONIOM calculations using the two- and/or three-layer model chemistries were applied to mimic the interaction of water with the basal graphitic layer of HOPG material. The high-level layer in the ONIOM approach is treated at the electron correlated second-order Moller-Plesset perturbation (MP2/6-31G*) level. On the basis of the results obtained, the formation of structural defect sites, molecular and dissociative adsorption complexes of water on a regular and on structural defect sites, the discrepancy in the nature of the surface O-H and C-H groups appeared on SWNT and HOPG materials has been briefly discussed. It was shown that the dissociation of water is highly endothermic on regular sites of HOPG while the energy needed for dissociation decreases substantially if it proceeds on structural defect sites. This finding points out indirectly that the dissociation probability of water increases on SWNT materials as compared to HOPG because of the presence of a larger number of structural defect sites
MP2 STUDY ON DECOMPOSITION OF NITROUS OXIDE ON THE Ga-ZSM-5
V.N. Solkan*, G.M. Zhidomirov
(*Zelinsky Institute of Organic Chemistry, Moscow, Russia)
Int. J. Quantum Chem., 108(14) (2008) pp. 2732-2743.
The reaction mechanism for nitrous oxide decomposition has been studied on gallium site in Ga-ZSM-5 using the MP2/6-31+G(d) method. The active centers were taken to be mononuclear [Ga]+, [Ga═O]+, and [GaO2]+ and the surrounding portion of the zeolite was represented by a 3T cluster, namely [AlSi2O4H8]-. The first elementary step of N2O decomposition involves the formation of [GaO]+ and the release of N2. The metal-oxo species produced in this step then reacts with N2O again, to release N2 and form [GaO2]+. The calculated activation energies at MP2 level for N2O dissociation on Ga-ZSM-5 and GaO-ZSM-5 are 15.7 and 26.5 kcal/mol at 298 K, respectively. The third elementary step of N2O decomposition on GaO2-ZSM-5 involves the formation of [GaO3]+ and the release of N2. The calculated activation energy at MP2 level for N2O dissociation on GaO2-ZSM-5 is 43.7 kcal/mol. Four- order perturbation theory (MP4//MP2) predicts that the activation barriers for nitrous oxide dissociation at 298 K on Ga-ZSM-5, GaO-ZSM-5, and GaO2-ZSM-5 are 13.9, 13.0, and 34.4 kcal/mol, respectively. The calculated energy for desorption of singlet O2 from the 3T-[Ga(O)3]+ cluster at MP2 level is 33.4 kcal/mol. When one takes into account the entropy gained on desorption of singlet O2, the contribution of entropy to the free energy of desorption is TΔS = 12.3 kcal/mol at 298 K. The calculated energy of the singlet oxygen desorption from 3T-[OGaO2]+ cluster ΔH (298 K) = +43.57 kcal/mol and ΔG(298 K) = 30.13 kcal/mol is significantly higher than the barriers of the singlet molecular oxygen desorption from 3T-[Ga(O)3]+ cluster.
SURFACE SPECIES OF TITANIUM(IV) AND TITANIUM(III) IN MgCl2-SUPPORTED ZIEGLER-NATTA CATALYSTS. A PERIODIC DENSITY FUNCTIONAL THEORY STUDY
D.V. Stukalov, I.L. Zilberberg, V.A. Zakharov
Macromol., 42(21) (2009) pp. 8165-8171.
A systematic consideration of different Ti(IV) and Ti(III) species on the (104) and (110) MgCl2 surfaces has been implemented within DFT using cyclic boundary conditions. Some new mononuclear and dinuclear surface complexes of Ti(IV) and Ti(III) were obtained due to implication of zip coordination mode. A possible spin state of dinuclear Ti(III) species was thoroughly studied: antiferromagnetic (ESR silent) state proved to be the most preferable in a number of cases. The zip antiferromagnetic Ti2Cl6 complexes residing on the dominant (104) MgCl2 surface make it possible to rationalize the fact that the most part of Ti(III) incorporated in activated MgCl2 is ESR silent. Besides, these species produce aspecific active sites, thus explaining that aspecific centers significantly prevail over stereospecific one according to kinetic data on the simplest TiCl4/MgCl2 + AlR3 system.
THEORETICAL STUDY OF CARBON SPECIES ON Pd(111): COMPETITION BETWEEN MIGRATION OF C ATOMS TO THE SUBSURFACE INTERLAYER AND FORMATION OF CN CLUSTERS ON THE SURFACE
S.M. Kozlov, I.V. Yudanov, H.A. Aleksandrov*,**, N. Rösch*
(*Technische Universität München, Garching, Germany;
**University of Sofia, Sofia, Bulgaria)
Phys. Chem. Chem. Phys., 1(46) (2009) pp. 10955-10963.
Subsurface carbon species of Pd catalysts recently attracted considerable attention because they affect the selectivity of hydrogenation reactions. The migration of C atoms from the Pd(111) surface to interstitial subsurface sites was calculated to be energetically favorable. Yet, thermodynamically more stable is a graphene-like phase on the Pd surface. Applying a density functional method on periodic models, the formation of Cn (n = 2–4) clusters on Pd(111) was explored. At low coverage, carbon monomers on the surface and at octahedral subsurface sites were calculated to be more stable than dimer species, C2, on the surface. However, at a C coverage of about half a monolayer, the formation of C2 and C3 species, precursors of a graphene phase, becomes competitive with migration of C monomers to octahedral subsurface sites. While discussing these findings, the authors also addressed the problem of C1 formation on Pd catalysts from simple organics.
MECHANISM OF SELECTIVE HYDROGENATION OF α,β-UNSATURATED ALDEHYDES ON SILVER CATALYSTS: A DENSITY FUNCTIONAL STUDY
K.H. Lim*,**, A.B. Mohammad*, I.V. Yudanov, K.M. Neyman***, M. Bron****, P. Claus****, N. Rösch*
(*Technische Universität München, Garching, Germany; **Nanyang Technological University, Singapore; ***ICREA, Barcelona, Spain;
****Technische Universität Darmstadt, Darmstadt, Germany)
J. Phys. Chem. C,
113(30) (2009) pp 13231-13240.
Supported silver catalysts exhibit a remarkably high selectivity in the industrially important hydrogenation of α,β unsaturated aldehydes to unsaturated alcohols. Density functional calculations have been carried out to clarify factors that affect the catalytic function of silver in hydrogenating unsaturated aldehydes. The activity and the selectivity of model silver catalysts for acrolein, the simplest, yet most difficult unsaturated aldehyde to be selectively hydrogenated was examined. The focus has been made on describing bulky catalyst particles, represented by sites on extended silver surfaces, on the regular clean Ag(110) surface and the surface Osub/Ag(111) with subsurface oxygen centers. On Ag(110) the results imply propanal, the undesired saturated aldehyde, to be the main product. In contrast, the calculations suggest a very high selectivity of Osub/Ag(111) for the corresponding unsaturated alcohol, allyl alcohol, although the activity of this system is lower than that of clean silver. At variance with Pt(111), where the selectivity to allyl alcohol is strongly reduced by the hindered desorption of the latter, allyl alcohol and propanal products are predicted to desorb easily from both Ag(110) and Osub/Ag(111) at common reaction temperatures. Inherent limitations for an accurate description of the chemical regioselectivity by contemporary computational methods have been also analyzed.
KOOPMANS’ THEOREM IN THE RESTRICTED OPEN-SHELL HARTREE−FOCK METHOD: I. A VARIATIONAL APPROACH
B.N. Plakhutin, E.R. Davidson*
(*University of Washington, Seattle, Washington)
J. Phys. Chem. A, 113(45) (2009) pp 12386-12395.
A general formulation of Koopmans’ theorem is derived for high-spin half-filled open shells in the restricted open-shell Hartree−Fock (ROHF) method based on a variational treatment of both the initial (nonionized) open-shell system under study, e.g., X, and the corresponding high-spin ions Xk+, Xm+, and Xv− having a hole or an extra electron in the closed, open, and virtual shell, respectively. The ions are treated within a FCI-RAS (full CI in the restricted active space) method with a use of arbitrary ROHF orbitals optimal for the initial system. It was shown that the desired canonical ROHF orbitals and orbital energies satisfying Koopmans’ theorem, first defined within the canonical ROHF treatment [Plakhutin; et al. J. Chem. Phys. 2006, 125, 204110], generally appear as the natural CI orbitals and the eigenvalues of CI matrices for the respective ions X±. A comparison is performed between the results derived with the present CI approach and the canonical ROHF method for the specific case where the canonical orbital energies satisfying Koopmans’ theorem do not satisfy the Aufbau principle.
PAIRED ORBITALS FOR DIFFERENT SPINS EQUATIONS
I.L. Zilberberg, S.F. Ruzankin
J. Comput. Chem., 31(1) (2009) pp. 84-89.
Eigenvalue-type equations for Löwdin-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 eigenvectors 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 Sz = 0 BS solutions for the systems with antiferromagnetic structure.
PROTON ENVIRONMENT OF REDUCED RIESKE IRON−SULFUR CLUSTER PROBED BY TWO-DIMENSIONAL ESEEM SPECTROSCOPY
D.R.J. Kolling*, R.I. Samoilova**, A.A. Shubin, A.R. Crofts**, S.A. Dikanov*
(*University of Illinois, Urbana, Illinois; **Institute of Chemical Kinetics and Combustion, Novosibirsk, Russia)
J. Phys. Chem. A, 113(4) (2009) pp 653-667.
The proton environment of the reduced [2Fe-2S] cluster in the water-soluble head domain of the Rieske iron−sulfur protein (ISF) from the cytochrome bc1 complex of Rhodobacter sphaeroides has been studied by orientation-selected X-band 2D ESEEM. The 2D spectra show multiple cross-peaks from protons, with considerable overlap. Samples in which 1H2O water was replaced by 2H2O were used to determine which of the observed peaks belong to exchangeable protons, likely involved in hydrogen bonds in the neighborhood of the cluster. By correlating the cross- peaks from 2D spectra recorded at different parts of the EPR spectrum, lines from nine distinct proton signals were identified. Assignment of the proton interaction with electrons of Fe(III) and Fe(II) ions, using the high-resolution structure of ISF from Rb. sphaeroides. Analysis of experimental and calculated tensors has led to conclude that even 2D spectra do not completely resolve all contributions from nearby protons. Particularly, the seven resolved signals from nonexchangeable protons could be produced by at least 13 protons. The contributions from exchangeable protons were resolved by difference spectra (1H2O minus 2H2O), and assigned to two groups of protons with distinct anisotropic hyperfine values. The largest measured coupling exceeded any calculated value. This discrepancy could result from limitations of the point dipole approximation in dealing with the distribution of spin density over the sulfur atoms of the cluster and the cysteine ligands, or from differences between the structure in solution and the crystallographic structure. The approach demonstrated here provides a paradigm for a wide range of studies in which hydrogen-bonding interactions with metallic centers has a crucial role in understanding the function
Страницы 1 - 1 из 16
Начало | Пред. | 1 2 3 4 5 | След. | Конец | Все