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

RSC Advances ◽  
2014 ◽  
Vol 4 (43) ◽  
pp. 22411-22418 ◽  
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.

Density Functional Calculations of Carrier Induced Ferromagnetism in Co Doped Cd[sub 28]Se[sub 28] Nanocluster

2011 ◽  
Author(s):  
Saurabh Ghosh ◽  
Biplab Sanyal ◽  
G. P. Das ◽  
Alka B. Garg ◽  
R. Mittal ◽  
...  
Keyword(s):  
Density Functional Calculations ◽  
Density Functional ◽  
Co Doped

Ab Initio Studies of Nb Doping Effect on the Formation and Diffusion of Oxygen Vacancy and Ti Interstitial in Rutile TiO2

2011 ◽  
Vol 304 ◽  
pp. 142-147 ◽  
Author(s):  
Xu Wang ◽  
Fu He Wang
Keyword(s):  
Activation Energy ◽  
Oxygen Vacancy ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Formation Energy ◽  
Suppressive Effect ◽  
Nb Doping ◽  
O Vacancy ◽  
And Migration ◽  
And Diffusion

The effect of Nb doping on the formation and diffusion of O vacancies and interstitial Ti in rutile TiO2 are studied by the use of ab initio density-functional calculations. Our calculation showed that the activation energy for the diffusion of O vacancy with Nb doping is higher than that of pure. That owing to suppressive effect of Nb doping on the formation of O vacancy. Different from the effect of Nb doping on O vacancy, both of the formation energy and migration barrier of interstitial Ti increase with the Nb doping. Our calculated results may be one of the reasons why Nb doping can improve oxidation resistance of γ-TiAl.

Magnetoelectric Interactions in Mn- and Co-Doped Incipient Ferroelectrics from Density Functional Calculations

2012 ◽  
Vol 427 (1) ◽  
pp. 70-77
Author(s):  
I. V. Kondakova ◽  
R. O. Kuzian ◽  
V. V. Laguta ◽  
A.-M. Dare ◽  
L. Raymond ◽  
...  
Keyword(s):  
Density Functional Calculations ◽  
Density Functional ◽  
Co Doped

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

2010 ◽  
Vol 65 (3) ◽  
pp. 231-s261 ◽  
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.

Electronic and optical properties of Co-doped 3C-SiC from density functional calculations

2014 ◽  
Vol 196 ◽  
pp. 28-31 ◽  
Author(s):  
P.L. Zhou ◽  
S.K. Zheng ◽  
Lei Ma ◽  
Jingfang He ◽  
Yan Tian ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Electronic And Optical Properties ◽  
Co Doped

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

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.

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

RSC Advances ◽  
2016 ◽  
Vol 6 (107) ◽  
pp. 105888-105894 ◽  
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.

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

2014 ◽  
Vol 176 ◽  
pp. 381-392 ◽  
Author(s):  
Yun Zhao ◽  
Guangxu Chen ◽  
Nanfeng Zheng ◽  
Gang Fu
Keyword(s):  
Co Oxidation ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Structural Models ◽  
Pt Nanoparticles ◽  
Structure Sensitivity ◽  
Catalytic Cycle ◽  
Dft Study ◽  
Bond Strengths ◽  
Catalytic Cycles

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.

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

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.

SUBTLE INTERPLAY BETWEEN HYDROGEN AND MAGNETISM IN Co DOPED ZnO

2012 ◽  
Vol 01 (01) ◽  
pp. 1250001
Author(s):  
Y. B. ZHANG ◽  
M. H. N. ASSADI ◽  
S. LI
Keyword(s):  
Magnetic Properties ◽  
Point Defect ◽  
First Principles ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Strong Tendency ◽  
Doped Zno ◽  
Co Doped

The effects of hydrogen, either interstitial (HI) or substitutional (Ho), on magnetic properties of Co doped ZnO (ZnO:Co) have been systematically investigated using first-principles density functional calculations. The study discovers the correlation between the distribution of Co ions and the hydrogen point defect and magnetism. It is found that Co ions and hydrogen have a strong tendency toward aggregation and hydrogen mainly contributes to the room temperature ferromagnetism observed experimentally in ZnO:Co . Furthermore, in ZnO:Co , the formation of Ho with four-fold hydrogenic bonds is favored over HI by 0.4 eV.

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