Studies of the Chemical Properties of Size Selected Metal Clusters: Kinetics and Saturation

1990 ◽  
Vol 206 ◽  
Author(s):  
Donald M. Cox ◽  
Robert O. Brickman ◽  
Kathleen Creegan ◽  
Andrew Kaldor
Keyword(s):  
Metal Clusters ◽  
Gold Cluster ◽  
Chemical Properties ◽  
Gold Clusters ◽  
Transition Metal Clusters ◽  
Experimental Conditions ◽  
Au Clusters ◽  
Hydrogen Deuterium ◽  
Small N ◽  
Small Clusters

ABSTRACTOur studies of small (n=2−40) gas phase transition metal clusters (cations, neutrals and anions) have revealed a number of size-dependent chemical and physical properties. This paper will discuss results involving activated dissociative molecular chemisorption of hydrogen (deuterium) and small alkanes on cationic, neutral and anionic platinum and gold clusters. For example, we have yet to find any size gold cluster anion to exhibit measurable reactivity towards di-deuterium, but reactivity is observed on small (n<15) gold cations and very small (n<9) neutral gold clusters. Methane or ethane chemisorption occurs most readily only on small Pt and Au cluster cations and least rapidly, if at all, on cluster anions. The larger Pt and Au clusters are found to be non-reactive towards the alkanes under our experimental conditions.At the other extreme, at steady state, small clusters of Pt, Rh, Ni, Pd, V, Nb, and Ta are hydrogen “rich” exhibiting H/M stoichiometrics >> 1. These results are consistent with a limited data base on supported clsutes obtained via EXAFS measurements and have important implications for catalytic reactions involving hydrogen and light hydrocarbons.

scholarly journals Temperature dependent chiroptical response of sigmoidal gold clusters: probing the stability of chiral metal clusters

2018 ◽  
Vol 9 (25) ◽  
pp. 5614-5622 ◽  
Author(s):  
Ping Guo ◽  
Biao Yang ◽  
Li Zhang ◽  
Liang Zhao
Keyword(s):  
Metal Clusters ◽  
Gold Cluster ◽  
Gold Clusters ◽  
Cluster Compounds ◽  
Structural Factors ◽  
Temperature Dependent ◽  
Cluster Stability ◽  
The Stability

Three chiral gold cluster compounds are herein selected to probe how structural factors influence the cluster stability upon heating.

scholarly journals Adsorption Behavior of an Adamantane Derivative on Metal Clusters – DFT Simulation Studies

2021 ◽  
Author(s):  
Jamelah S. Al-Otaibi ◽  
Y. Sheena Mary ◽  
Y. Shyma Mary
Keyword(s):  
Metal Clusters ◽  
Gold Cluster ◽  
Metal Cluster ◽  
Dft Method ◽  
Adamantane Derivative ◽  
Simulation Studies ◽  
Transition Metal Clusters ◽  
Gold Nanocluster ◽  
Dft Simulation ◽  
Drug Complex

Abstract Investigation of the adsorption properties of 3-(adamantan-1-yl)-4-phenyl-1-[(4-phenylpiperazin-yl)methyl]-1H-1,2,4-triazole-5(4H)-thione (APT) with metal clusters (mC: Ag, Au and Cu) are reported using DFT method. APT is found to form stable cluster with transition metal clusters of copper, silver and gold. The drug-cluster complexation energy is slightly more for the gold nanocluster-drug complex. Dipole moment of the drug-gold cluster is found to be higher than that of the other systems. SERS studies demonstrate improved Raman signals for multiple wavenumbers of all APT-metal cluster complexes. Different spectroscopic, chemical and electronic properties are also investigated.

Evolution of the structural, energetic, and electronic properties of the 3d, 4d, and 5d transition-metal clusters (30 TMn systems for n = 2–15): a density functional theory investigation

2017 ◽  
Vol 19 (23) ◽  
pp. 15484-15502 ◽  
Author(s):  
Anderson S. Chaves ◽  
Maurício J. Piotrowski ◽  
Juarez L. F. Da Silva
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Density Functional ◽  
Metal Clusters ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Transition Metal Clusters ◽  
Functional Theory ◽  
Physical And Chemical ◽  
And Chemical Properties

Subnanometric transition-metal (TM) clusters have attracted great attention due to their unexpected physical and chemical properties, leastwise compared to their bulk counterparts.

ALTERNATIVE MICROSCOPIC APPROACH TO THE PHOTOABSORPTION OF SMALL CLUSTERS

1996 ◽  
Vol 10 (07) ◽  
pp. 241-268
Author(s):  
S. GRABOWSKI ◽  
M.E. GARCIA ◽  
K.H. BENNEMANN
Keyword(s):  
Cross Section ◽  
Atomic Structure ◽  
Structural Changes ◽  
Metal Clusters ◽  
Collective Excitations ◽  
Transition Metal Clusters ◽  
Coulomb Interactions ◽  
Microscopic Approach ◽  
Small Clusters ◽  
Localized Electrons

A Wannier-type electronic theory to calculate self-consistently the photoabsorption spectra of small clusters is presented. This approach, that applies to systems with mainly localized electrons, permits a detailed analysis of the dependence of the absorption cross-section on atomic structure and cluster size. In addition the approach also allows a transparent identification of the optical excitations contributing to the different absorption peaks. By applying this theory to neutral and ionized mercury clusters one finds that both exciton- and plasmon-like excitations are present in the absorption spectra. Furthermore the dependence of the optical response on short- and long-range Coulomb interactions, on structural changes of the system and on the specific bonding character of the cluster is studied. It is demonstrated that the broadening of the collective excitations in small clusters with localized electrons depends sensitively on the atomic structure, in particular at the surface. The limitations of this theory and its extension to systems having also delocalized electrons, like noble- and transition-metal clusters are discussed.

Competitive adsorption of phenol and toluene onto silica-supported transition metal clusters for biofuel purification

2021 ◽  
Author(s):  
Saber Gueddida ◽  
Michael Badawi ◽  
Tejraj Aminabhavi ◽  
Sébastien Lebègue
Keyword(s):  
Transition Metal ◽  
Competitive Adsorption ◽  
Metal Clusters ◽  
Hydrocarbon Fuel ◽  
Energy Performance ◽  
Transition Metal Clusters ◽  
Gas Emissions ◽  
Toxic Gas

Biomass-based renewable hydrocarbon fuel is a complex mix that contains many oxygenating substances, in particular phenolics, which leads to adverse consequences such as reduced engine energy performance and increased toxic gas emissions.

Soluble lanthanide-transition-metal clusters Ln36Co12 as effective molecular electrocatalysts for water oxidation

2021 ◽  
Vol 57 (29) ◽  
pp. 3611-3614
Author(s):  
Rong Chen ◽  
Chao-Long Chen ◽  
Ming-Hao Du ◽  
Xing Wang ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Synergistic Effect ◽  
Water Oxidation ◽  
Metal Clusters ◽  
Bond Formation ◽  
Transition Metal Clusters ◽  
Oxidation Activity ◽  
Acidic Conditions ◽  
Effective Water

The stable 48-metal Ln36Co12 clusters show an effective water oxidation activity under weak acidic conditions because of the synergistic effect between lanthanide and transition metals in O–O bond formation.

scholarly journals Tailoring of Hydrotalcite-Derived Cu-Based Catalysts for CO2 Hydrogenation to Methanol

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1058 ◽  
Author(s):  
Leone Frusteri ◽  
Catia Cannilla ◽  
Serena Todaro ◽  
Francesco Frusteri ◽  
Giuseppe Bonura
Keyword(s):  
Metallic Copper ◽  
Chemical Properties ◽  
Active Phase ◽  
Co2 Hydrogenation ◽  
High Dispersion ◽  
Experimental Conditions ◽  
Typical Structure ◽  
Methanol Production ◽  
Physico Chemical ◽  
Space Time Yield

Ternary CuxZnyAlz catalysts were prepared using the hydrotalcite (HT) method. The influence of the atomic x:y:z ratio on the physico-chemical and catalytic properties under CO2 hydrogenation conditions was probed. The characterization data of the investigated catalysts were obtained by XRF, XRD, BET, TPR, CO2-TPD, N2O chemisorption, SEM, and TEM techniques. In the “dried” catalyst, the typical structure of a hydrotalcite phase was observed. Although the calcination and subsequent reduction treatments determined a clear loss of the hydrotalcite structure, the pristine phase addressed the achievement of peculiar physico-chemical properties, also affecting the catalytic activity. Textural and surface effects induced by the zinc concentration conferred a very interesting catalyst performance, with a methanol space time yield (STY) higher than that of commercial systems operated under the same experimental conditions. The peculiar behavior of the hydrotalcite-like samples was related to a high dispersion of the active phase, with metallic copper sites homogeneously distributed among the oxide species, thereby ensuring a suitable activation of H2 and CO2 reactants for a superior methanol production.

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