Cobalt nanoclusters

Ivanov-OMskiy V.I., Kolobov A.V., Lodygin A.B., Yastrebov S.G. Distribution on the sizes of cobalt nanoclusters in the amorphous carbon matrix. Fiz. Tech. Polupr. (in Russian) 2004 38 1463-1465. 

V. Pokhmurskii, S. Komiy, V. Kopylets Computer Simulation of Binary Platinum-Cobalt Nanoclusters Interaction with Oxygen, "Journal of Cluster Science", 22 (3), 449 58(2011). 

Different nanocrystals shapes are obtained by variation of the organic stabilizer type and its concentration. For instance, if organometallic compounds such as nickel bis-cyclooctene-l,5-diene(Ni(COD)2) are subjected to the heat treatment and decomposition in the presence of hexadecylamine (GDA) or trioctylphosphenoxide, the nanorods or nanospheres can be obtained [311]. The particles of bracelet shape and 27 nm size have been synthesized in Ref. [312]. The tetrahedral structures [313] have been obtained when the cobalt nanoclusters react with NaAOT/toluene at 130 °C. 

Gibson, C.P, Putzer, K.J. Synthesis and characterization of anisometric cobalt nanoclusters. Science 267, 1338-1340 (1995)... 

Kem and coworkers have also explored controllable, uniform metal deposition by employing TMV as a biotemplate. In their studies, the addressable amino acid side chains that function as metal nncleation sites are first activated with a metal complex, followed by incubation with the desired metal for metallization and its subsequent chemical reduction to form metal nanoparticles. By employing this approach of electroless deposition, discrete nickel, silver, and cobalt nanoclusters were selectively formed on the interior or exterior of the virus by controlling the pH and the activation complex used in the reaction. In addition... 

Figure 16 (top) A group of cobalt nanoclusters. The particles, which adopt a hexagonal or centered trigonal unit ceU, are preferentially deposited as oriented (001) plates, (bottom) A single cobalt nanocluster. The orientations of the (100) and (010) zone axes were determined by SAD and TEM. (From Ref. 141.)... 

By applying an approach similar to the one taken with the unpromoted M0S2 nanoclusters, we recently managed to synthesize a model system for the promoted CoMoS catalyst 119). As a result of co-deposition of molybdenum and cobalt onto the Au(l 1 1) crystal during exposure to an H2S atmosphere and subsequent annealing, crystalline CoMoS clusters formed on the Au(l 1 1) terraces. As shown in Fig. 24, the main new finding is that the CoMoS nanoclusters now adopt a... 

Fig. 24. Atom-resolved STM image of a CoMoS nanocluster. The size is 51 Ax 52A, and Ft = -95.2mV and /. = 0.81 nA. Note the intense brim associated with the cobalt-substituted sulfur edge (shorter edges).

On the basis of the detailed atomic-scale information provided by the STM images, a structural model of the CoMoS nanoclusters is proposed in which cobalt atoms have replaced molybdenum atoms along the sulfur edges of hexagonally truncated nanoclusters. As depicted in the ball model in Fig. 25(a) and (c), a tetrahedral environment of the cobalt atoms is produced if the outermost protrusions are assumed to be sulfur monomers, which agrees well with spectroscopic results reported for supported CoMoS catalysts (93,137-139 and previous DFT investigations (128,140. ... 

Metallic species such as iron, nickel and cobalt are known to catalyze the growth of CNTs in the CVD process [168-170]. Because of the ready thermal curability of the hb-PYs, spin-coated films of organometallic polymers 81 and 82 are expected to restrict the agglomeration of the metallic nanoclusters in the CVD process and hence to provide nanoscopic catalyst seeds for the... 

Cobalt powder is an important material because of its magnetic properties. Its thermal formation normally requires high temperatures. It can be obtained by the sonochemical reduction of a divalent salt with hydrazine.62 The resulting nanoclusters flocculate and can be stored as a hydrated floe or dried to a powder. 

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