Mechanisms for CO oxidation on Fe(iii)–OH–Pt interface: a DFT study

The full catalytic cycle that involves the oxidation of two CO molecules is investigated here by using periodic density functional calculations. To simulate the nature of Fe(OH)x/Pt nanoparticles, three possible structural models, i.e., Fe(OH)x/Pt(111), Fe(OH)x/Pt(332) and Fe(OH)x/Pt(322), are built. We demonstrate that Fe(iii)–OH–Pt stepped sites readily react with CO adsorbed nearby to directly yield CO2 and simultaneously produce coordinatively unsaturated iron sites for O2 activation. By contrast, the created interfacial vacancy on Fe(OH)x/Pt(111) prefers to adsorb CO rather than O2, thus inhabiting the catalytic cycles of CO oxidation. We suggest that such structure sensitivity can be understood in terms of the bond strengths of Fe(iii)–OH.

Download Full-text

On the Effects of Doping on the Catalytic Performance of (La,Sr)CoO3. A DFT Study of CO Oxidation

Catalysts ◽

10.3390/catal9040312 ◽

2019 ◽

Vol 9 (4) ◽

pp. 312 ◽

Cited By ~ 2

Author(s):

Antonella Glisenti ◽

Andrea Vittadini

Keyword(s):

Catalytic Activity ◽

Co Oxidation ◽

Density Functional Calculations ◽

Density Functional ◽

Formation Energy ◽

Oxygen Vacancies ◽

Catalytic Performance ◽

Energy Profiles ◽

High Concentrations ◽

3D Impurities

The effects of modifying the composition of LaCoO3 on the catalytic activity are predicted by density functional calculations. Partially replacing La by Sr ions has benefical effects, causing a lowering of the formation energy of O vacancies. In contrast to that, doping at the Co site is less effective, as only 3d impurities heavier than Co are able to stabilize vacancies at high concentrations. The comparison of the energy profiles for CO oxidation of undoped and of Ni-, Cu-m and Zn-doped (La,Sr)CoO3(100) surface shows that Cu is most effective. However, the effects are less spectacular than in the SrTiO3 case, due to the different energetics for the formation of oxygen vacancies in the two hosts.

Download Full-text

Sind Metalloprotonencryptanden möglich? – DFT-Studie zur Protonenaffinität von [2.2.2]-analogen Metallocryptanden / Can Metallocryptands act as Proton Cages? – DFT Study of Proton Affinity in [2.2.2]-analogousMetallocryptands Sind Metalloprotonencryptanden m¨oglich? – DFT-Studie zur Protonenaffinit¨at von [2.2.2]-analogen Metallocryptanden

Zeitschrift für Naturforschung B ◽

10.1515/znb-2010-0303 ◽

2010 ◽

Vol 65 (3) ◽

pp. 231-s261 ◽

Cited By ~ 6

Author(s):

Ralph Puchta ◽

Andreas Scheurer

Keyword(s):

Coordination Chemistry ◽

Gas Phase ◽

Proton Affinity ◽

Density Functional Calculations ◽

Density Functional ◽

Dft Study ◽

Proton Sponges

Based on density functional calculations (RB3LYP/LANL2DZp) the bicyclic metallocryptand [Pd3(L2)2] [(L2)3−: 1,1´ ,1´´-nitrilotris(5,5-dimethylhexane-2,4-dione trianion)] shows the same high gas-phase basicity (−257.1 kcal mol−1) as Lehn’s [2.2.2] cryptand (−254.4 kcal mol−1). This illustrates that the concept of metallotopomers adopted by Saalfrank et al. can be applied to design proton sponges as well as proton cryptands by metallosupramolecular coordination chemistry. The slightly higher gas-phase proton affinity of [Pd3(L2)2] compared to [2.2.2] can be attributed to the smaller cavity in the metallotopomer.

Download Full-text

What Silicon Nanocluster is Most Likely Formed in Etching Experiments? Theoretical DFT Study

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.113 ◽

2008 ◽

Vol 8 (7) ◽

pp. 3478-3482

Author(s):

Nurbosyn U. Zhanpeisov ◽

Hiroshi Fukumura

Keyword(s):

Absorption Spectra ◽

Density Functional Calculations ◽

Density Functional ◽

Electrochemical Etching ◽

Time Dependent ◽

Cluster Models ◽

Dft Study ◽

Basis Sets ◽

Self Healing ◽

Tddft Calculations

Density functional calculations at the B3LYP/6-31G* level were performed for Si nanoclusters of ca.1 nm in size. The structural, energetic, electronic as well as the estimated absorption spectra by the time-dependent DFT (TDDFT) calculations using varied functionals and basis sets for the representative cluster models are all in favor of the formation of most probable Si35H36 nanocluster in recent electrochemical etching experiments. The nanostructure has a complete H-termination at the borderline regions and lacks from the presence of any defects like surface Si—Si dimer units formed via self-healing of dangling Si—Si bonds or from any relatively short H…H contacts.

Download Full-text

Density functional investigations on the catalytic cycle of the hydrogenation of aldehydes catalyzed by an enhanced ruthenium complex: an alcohol-bridged autocatalytic process

RSC Advances ◽

10.1039/c4ra12466a ◽

2015 ◽

Vol 5 (4) ◽

pp. 2827-2836 ◽

Cited By ~ 1

Author(s):

Xi Lu ◽

Qian Liu ◽

Xiaoyin Wang ◽

Runjiao Cheng ◽

Mingtao Zhang ◽

...

Keyword(s):

Density Functional ◽

Ruthenium Complex ◽

Catalytic Cycle ◽

Dft Study ◽

Ru Complex ◽

Autocatalytic Process

A DFT study of the catalytic cycle of PhCHO hydrogenation catalyzed by Casey’s Ru-complex.

Download Full-text

Adsorption and decarbonylation of furfural over H-ZSM-5 zeolite: a DFT study

RSC Advances ◽

10.1039/c6ra24631a ◽

2016 ◽

Vol 6 (107) ◽

pp. 105888-105894 ◽

Cited By ~ 20

Author(s):

Patipan Charoenwiangnuea ◽

Thana Maihom ◽

Pipat Kongpracha ◽

Jakkapan Sirijaraensre ◽

Jumras Limtrakul

Keyword(s):

Density Functional Calculations ◽

Density Functional ◽

Dft Study ◽

Zeolite A

The biomass-derived furfural adsorption and decarbonylation to furan over H-ZSM-5 (see picture) have been unraveled by means of density functional calculations with the M06-2X functional.

Download Full-text

Structure Sensitivity of CO Oxidation on Co3O4: A DFT Study

ChemPhysChem ◽

10.1002/cphc.201200807 ◽

2012 ◽

Vol 14 (1) ◽

pp. 204-212 ◽

Cited By ~ 51

Author(s):

Xian-Yong Pang ◽

Chang Liu ◽

Dui-Chun Li ◽

Cun-Qin Lv ◽

Gui-Chang Wang

Keyword(s):

Co Oxidation ◽

Structure Sensitivity ◽

Dft Study

Download Full-text

Density Functional Theory Study into the Reaction Mechanism of Isonitrile Biosynthesis by the Nonheme Iron Enzyme ScoE

Topics in Catalysis ◽

10.1007/s11244-021-01460-x ◽

2021 ◽

Author(s):

Hafiz Saqib Ali ◽

Sidra Ghafoor ◽

Sam P. de Visser

Keyword(s):

Reaction Mechanism ◽

Hydrogen Atom ◽

Proton Transfer ◽

Active Site ◽

Density Functional ◽

Active Species ◽

Nonheme Iron ◽

Catalytic Cycle ◽

Hydrogen Atom Abstraction ◽

Catalytic Cycles

AbstractThe nonheme iron enzyme ScoE catalyzes the biosynthesis of an isonitrile substituent in a peptide chain. To understand details of the reaction mechanism we created a large active site cluster model of 212 atoms that contains substrate, the active oxidant and the first- and second-coordination sphere of the protein and solvent. Several possible reaction mechanisms were tested and it is shown that isonitrile can only be formed through two consecutive catalytic cycles that both use one molecule of dioxygen and α-ketoglutarate. In both cycles the active species is an iron(IV)-oxo species that in the first reaction cycle reacts through two consecutive hydrogen atom abstraction steps: first from the N–H group and thereafter from the C–H group to desaturate the NH-CH2 bond. The alternative ordering of hydrogen atom abstraction steps was also tested but found to be higher in energy. Moreover, the electronic configurations along that pathway implicate an initial hydride transfer followed by proton transfer. We highlight an active site Lys residue that is shown to donate charge in the transition states and influences the relative barrier heights and bifurcation pathways. A second catalytic cycle of the reaction of iron(IV)-oxo with desaturated substrate starts with hydrogen atom abstraction followed by decarboxylation to give isonitrile directly. The catalytic cycle is completed with a proton transfer to iron(II)-hydroxo to generate the iron(II)-water resting state. The work is compared with experimental observation and previous computational studies on this system and put in a larger perspective of nonheme iron chemistry.

Download Full-text

DFT STUDY OF SOME TRIVALENT d- AND f-BLOCK METAL ION COMPLEXES OF ALLOXAN

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633613500521 ◽

2013 ◽

Vol 12 (06) ◽

pp. 1350052

Author(s):

RITA KAKKAR ◽

MAMTA BHANDARI ◽

RITU GABA

Keyword(s):

Density Functional Calculations ◽

Metal Ion ◽

Density Functional ◽

Vibrational Frequencies ◽

Dft Study ◽

Bidentate Ligands ◽

Metal Ion Complexes ◽

Alloxan Monohydrate ◽

Trigonal Prismatic

Density functional calculations have been employed to elucidate the structures of some six coordinated complexes of alloxan monohydrate with some d- and f-block metals. Alloxan monohydrate may exist in the mono-ionized or di-ionized form in its complexes, and both states were investigated. It is found that when the metal ion is coordinated to three bidentate ligands, the structures are nearly trigonal prismatic, but replacement of a bidendate ligand by two monovalent ligands changes the geometry to deformed octahedral. The metal-alloxanate bonding is largely ionic for the lanthanoids. The calculated vibrational frequencies are in agreement with the experimentally determined ones.

Download Full-text

DFT study on the effects of defect and metal-doping on the decomposition of H2S on the α-Fe2O3(0001) surface

RSC Advances ◽

10.1039/c4ra02485k ◽

2014 ◽

Vol 4 (43) ◽

pp. 22411-22418 ◽

Cited By ~ 15

Author(s):

Lixia Ling ◽

Jiajia Song ◽

Senpeng Zhao ◽

Riguang Zhang ◽

Baojun Wang

Keyword(s):

Density Functional Calculations ◽

Density Functional ◽

Dft Study ◽

Metal Doping ◽

Decomposition Mechanisms ◽

O Vacancy ◽

Co Doped

The adsorption and decomposition mechanisms of H2S on different α-Fe2O3(0001) surfaces, including Fe-vacancy, O-vacancy, sulfurized and Cu-, Zn- and Co-doped surfaces, have been studied systematically using periodic density functional calculations.

Download Full-text

DFT study on ruthenium-catalyzed decarbonylative annulation of an alkyne with six-membered hydroxychromone via C−H/C−C activation

Organic Chemistry Frontiers ◽

10.1039/d1qo01786a ◽

2022 ◽

Author(s):

Hong-Jing Long ◽

Lei Zhang ◽

Bing Lian ◽

De-Cai Fang

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Dft Study ◽

Density Functional Theory Study ◽

Functional Theory ◽

Catalytic Cycles

We report a density functional theory study on ruthenium-catalyzed decarbonylative annulation of an alkyne with six-membered hydroxychromone via C−H/C−C Activation. The plausible catalytic cycles involve O−H deprotonation, C−H activation, alkyne...

Download Full-text