Publications by authors named "Kazuki Nakatsuka"

We report the first preparation of small gold-nickel (AuNi) bimetallic nanoparticles (<5 nm) supported on titania by the method of galvanic replacement reaction (GRR), evidenced by the replacement of Ni atoms by Au atoms according to the stoichiometry of the reaction. We showed that this preparation method allowed not only the control of the gold and nickel contents in the samples, but also the formation of small bimetallic nanoparticles with strained core-shell structures, as revealed by aberration-corrected scanning transmission electron microscopy in combination with energy-dispersive X-ray spectroscopy mapping. The catalytic characterization by the probe reaction of semi-hydrogenation of butadiene showed that the resulting nickel-based nanocatalysts containing a small amount of gold exhibited higher selectivity to butenes than pure nickel catalysts and a high level of activity, closer to that of pure nickel catalysts than to that of pure gold catalysts.

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Metal organic frameworks (MOFs) are a class of porous organic-inorganic crystalline materials that have attracted much attention as H storage devices and catalytic supports. In this paper, the synthesis of highly-dispersed Ni nanoparticles (NPs) for the hydrogenation of olefins was achieved by employing Ni-MOF-74 as a precursor. Investigations of the structural transformation of Ni species derived from Ni-MOF-74 during heat treatment were conducted.

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Realizing accurate control of catalytically active centers on solid surfaces is one of the most essential goals in the development of functionalized heterogeneous catalysts. Controlled synthesis of carbon-supported Co catalysts from single-site to nanoparticles can be successfully achieved by the structural transformation of the deposited Co(salen) complex precursor under heat treatment. The obtained structures were characterized using techniques such as XRD, in situ XAFS, and TEM.

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To enhance the catalytic activity in a selective one-pot oxidation using in-situ generated H(2)O(2), a hydrophobically modified core-shell catalyst was synthesized by means of a simple silylation reaction using the fluorine-containing silylation agent triethoxyfluorosilane (TEFS, SiF(OEt)(3)). The catalyst consisted of a Pd-supported silica nanosphere and a mesoporous silica shell containing isolated Ti(IV) and F ions bonded with silicon (SiF bond). Structural analyses using XRD and N(2) adsorption-desorption suggested that the mesoporous structure and large surface area of the mesoporous shells were retained even after the modification.

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In the present study, we used proteomic research technology to develop a method for the screening and evaluation of material-binding peptides for protein immobilization. Using this screening method, soluble Escherichia coli proteins that preferentially adsorbed onto polycarbonate (PC) and poly(methylmethacrylate) (PMMA) as model plastic materials were first isolated and identified by 2-dimensional electrophoresis (2DE) combined with peptide mass fingerprinting (PMF). The genes of identified protein candidates (ELN, MLT, OMP, and BIF) that exhibited a hexahistidine tag (6×His-tag) were over-expressed by E.

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