The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Teiji Chihara - One of the best experts on this subject based on the ideXlab platform.
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solid state Molybdenum sulfide clusters with an octahedral metal framework as hydrogenation dehydrogenation and hydrogenolysis catalysts similar to the platinum group metals
Applied Catalysis A-general, 2015Co-Authors: Satoshi Kamiguchi, Sayoko Nagashima, Kazu Okumura, Kanako Arai, Hajime Iida, Teiji ChiharaAbstract:Abstract Solid-state Molybdenum sulfide clusters with a nonstoichiometric sulfur-deficient site, Cu x Mo 6 S 8− δ ( x = 2.94 and δ ≈ 0.3) and Mo 6 S 8– δ ( δ ≈ 0.4), catalyze the dehydrogenation of cyclohexene, the hydrogenation of alkyne, alkene, aldehyde, ketone, and nitrobenzene, and the hydrogenolysis of halogenobenzenes in a hydrogen stream above 300 °C. This catalytic behavior of the clusters is similar to that of the platinum group metals, which is attributable to the isoelectronicity of sulfur-coordinating Molybdenum Atom to the platinum group metals.
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Catalytic Cracking of Methyl tert-Butyl Ether to Isobutene over Brønsted and Lewis Acid Sites on Solid-state Molybdenum Sulfide Clusters with an Octahedral Metal Framework
Journal of Cluster Science, 2015Co-Authors: Satoshi Kamiguchi, Yasunari Seki, Akiharu Satake, Sayoko Nagashima, Kazu Okumura, Teiji ChiharaAbstract:Solid-state Molybdenum sulfide clusters with an octahedral metal framework, the Chevrel phases, are applied to the catalytic cracking of methyl tert -butyl ether (MTBE) to yield isobutene. The copper salt of the nonstoichiometric sulfur-deficient cluster, Cu_ x Mo_6S_8− δ ( x = 2.94 and δ ≈ 0.3), after storing in air, is thermally activated in a hydrogen stream, followed by the reaction with MTBE. Two kinds of catalytically active sites develop depending on the activation temperature: one developed at 100–200 °C is a Brønsted-acidic hydroxo ligand on the copper cation while the other developed at 350–400 °C is a Lewis-acidic coordinatively unsaturated Molybdenum Atom with a sulfur-deficient site. A nonstoichiometric sulfur-deficient neutral cluster Mo_6S_8− δ ( δ ≈ 0.4) also catalyzes the cracking reaction when activated at 400 °C.
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application of solid state Molybdenum sulfide clusters with an octahedral metal framework to catalysis ring opening of tetrahydrofuran to butyraldehyde
Journal of Cluster Science, 2013Co-Authors: Satoshi Kamiguchi, Sayoko Nagashima, Kazu Okumura, Kunio Takeda, Ryu Kajio, Teiji ChiharaAbstract:Solid-state Molybdenum sulfide clusters with an octahedral metal framework, the superconducting Chevrel phases, are applied to catalysis. The cluster of copper salt, Cu x Mo6S8 (x = 2.94), stored in air is treated in a hydrogen stream above 300 °C. The activated cluster exhibits catalytic activity for the ring-opening of tetrahydrofuran, yielding butyraldehyde. Cyclic ethers such as trimethylene oxide and tetrahydropyran are also converted to the corresponding aldehydes. The cluster contains nonstoichiometric defects of sulfur Atoms. Oxygen Atoms are incorporated at the sulfur-deficient sites upon storage in air, but they are removed from the sites by the activation in a hydrogen stream. The resulting coordinatively unsaturated Molybdenum Atoms are catalytically active for the ring-opening reaction. The Molybdenum Atom in an intermediate oxidation state around 2+ is moderately coordinated by the oxygen of tetrahydrofuran and favorably releases the produced aldehyde. The neutral cluster Mo6S8, which has such sulfur-deficient sites, also catalyzes the reaction.
Satoshi Kamiguchi - One of the best experts on this subject based on the ideXlab platform.
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solid state Molybdenum sulfide clusters with an octahedral metal framework as hydrogenation dehydrogenation and hydrogenolysis catalysts similar to the platinum group metals
Applied Catalysis A-general, 2015Co-Authors: Satoshi Kamiguchi, Sayoko Nagashima, Kazu Okumura, Kanako Arai, Hajime Iida, Teiji ChiharaAbstract:Abstract Solid-state Molybdenum sulfide clusters with a nonstoichiometric sulfur-deficient site, Cu x Mo 6 S 8− δ ( x = 2.94 and δ ≈ 0.3) and Mo 6 S 8– δ ( δ ≈ 0.4), catalyze the dehydrogenation of cyclohexene, the hydrogenation of alkyne, alkene, aldehyde, ketone, and nitrobenzene, and the hydrogenolysis of halogenobenzenes in a hydrogen stream above 300 °C. This catalytic behavior of the clusters is similar to that of the platinum group metals, which is attributable to the isoelectronicity of sulfur-coordinating Molybdenum Atom to the platinum group metals.
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Catalytic Cracking of Methyl tert-Butyl Ether to Isobutene over Brønsted and Lewis Acid Sites on Solid-state Molybdenum Sulfide Clusters with an Octahedral Metal Framework
Journal of Cluster Science, 2015Co-Authors: Satoshi Kamiguchi, Yasunari Seki, Akiharu Satake, Sayoko Nagashima, Kazu Okumura, Teiji ChiharaAbstract:Solid-state Molybdenum sulfide clusters with an octahedral metal framework, the Chevrel phases, are applied to the catalytic cracking of methyl tert -butyl ether (MTBE) to yield isobutene. The copper salt of the nonstoichiometric sulfur-deficient cluster, Cu_ x Mo_6S_8− δ ( x = 2.94 and δ ≈ 0.3), after storing in air, is thermally activated in a hydrogen stream, followed by the reaction with MTBE. Two kinds of catalytically active sites develop depending on the activation temperature: one developed at 100–200 °C is a Brønsted-acidic hydroxo ligand on the copper cation while the other developed at 350–400 °C is a Lewis-acidic coordinatively unsaturated Molybdenum Atom with a sulfur-deficient site. A nonstoichiometric sulfur-deficient neutral cluster Mo_6S_8− δ ( δ ≈ 0.4) also catalyzes the cracking reaction when activated at 400 °C.
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application of solid state Molybdenum sulfide clusters with an octahedral metal framework to catalysis ring opening of tetrahydrofuran to butyraldehyde
Journal of Cluster Science, 2013Co-Authors: Satoshi Kamiguchi, Sayoko Nagashima, Kazu Okumura, Kunio Takeda, Ryu Kajio, Teiji ChiharaAbstract:Solid-state Molybdenum sulfide clusters with an octahedral metal framework, the superconducting Chevrel phases, are applied to catalysis. The cluster of copper salt, Cu x Mo6S8 (x = 2.94), stored in air is treated in a hydrogen stream above 300 °C. The activated cluster exhibits catalytic activity for the ring-opening of tetrahydrofuran, yielding butyraldehyde. Cyclic ethers such as trimethylene oxide and tetrahydropyran are also converted to the corresponding aldehydes. The cluster contains nonstoichiometric defects of sulfur Atoms. Oxygen Atoms are incorporated at the sulfur-deficient sites upon storage in air, but they are removed from the sites by the activation in a hydrogen stream. The resulting coordinatively unsaturated Molybdenum Atoms are catalytically active for the ring-opening reaction. The Molybdenum Atom in an intermediate oxidation state around 2+ is moderately coordinated by the oxygen of tetrahydrofuran and favorably releases the produced aldehyde. The neutral cluster Mo6S8, which has such sulfur-deficient sites, also catalyzes the reaction.
Peter Krüger - One of the best experts on this subject based on the ideXlab platform.
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Adsorption and diffusion of a Molybdenum Atom on the TiO2(110) surface : A first-principles study
Physical Review B, 2007Co-Authors: A.m. Asaduzzaman, Peter KrügerAbstract:A study on the structure and energetics of a single Molybdenum Atom adsorbed on the $\mathrm{Ti}{\mathrm{O}}_{2}(110)$ surface is reported. All possible adsorption sites have been determined. Moreover, it is found that incorporation of the Mo Atom into the first surface layer leads to considerably more stable structures than on any adsorption site. Different channels for migration of the Molybdenum Atom have been identified. The diffusion barriers of these channels have been determined. The results on structure and energetics are discussed by analyzing the electronic properties of the $\mathrm{Mo}∕\mathrm{Ti}{\mathrm{O}}_{2}(110)$ systems.
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Adsorption and diffusion of a Molybdenum Atom on the TiO2„110... surface : A first-principles study.
Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2007Co-Authors: A.m. Asaduzzaman, Peter KrügerAbstract:A study on the structure and energetics of a single Molybdenum Atom adsorbed on the TiO2110 surface is reported. All possible adsorption sites have been determined. Moreover, it is found that incorporation of the Mo Atom into the first surface layer leads to considerably more stable structures than on any adsorption site. Different channels for migration of the Molybdenum Atom have been identified. The diffusion barriers of these channels have been determined. The results on structure and energetics are discussed by analyzing the electronic properties of the Mo/TiO2110 systems.
Kazu Okumura - One of the best experts on this subject based on the ideXlab platform.
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solid state Molybdenum sulfide clusters with an octahedral metal framework as hydrogenation dehydrogenation and hydrogenolysis catalysts similar to the platinum group metals
Applied Catalysis A-general, 2015Co-Authors: Satoshi Kamiguchi, Sayoko Nagashima, Kazu Okumura, Kanako Arai, Hajime Iida, Teiji ChiharaAbstract:Abstract Solid-state Molybdenum sulfide clusters with a nonstoichiometric sulfur-deficient site, Cu x Mo 6 S 8− δ ( x = 2.94 and δ ≈ 0.3) and Mo 6 S 8– δ ( δ ≈ 0.4), catalyze the dehydrogenation of cyclohexene, the hydrogenation of alkyne, alkene, aldehyde, ketone, and nitrobenzene, and the hydrogenolysis of halogenobenzenes in a hydrogen stream above 300 °C. This catalytic behavior of the clusters is similar to that of the platinum group metals, which is attributable to the isoelectronicity of sulfur-coordinating Molybdenum Atom to the platinum group metals.
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Catalytic Cracking of Methyl tert-Butyl Ether to Isobutene over Brønsted and Lewis Acid Sites on Solid-state Molybdenum Sulfide Clusters with an Octahedral Metal Framework
Journal of Cluster Science, 2015Co-Authors: Satoshi Kamiguchi, Yasunari Seki, Akiharu Satake, Sayoko Nagashima, Kazu Okumura, Teiji ChiharaAbstract:Solid-state Molybdenum sulfide clusters with an octahedral metal framework, the Chevrel phases, are applied to the catalytic cracking of methyl tert -butyl ether (MTBE) to yield isobutene. The copper salt of the nonstoichiometric sulfur-deficient cluster, Cu_ x Mo_6S_8− δ ( x = 2.94 and δ ≈ 0.3), after storing in air, is thermally activated in a hydrogen stream, followed by the reaction with MTBE. Two kinds of catalytically active sites develop depending on the activation temperature: one developed at 100–200 °C is a Brønsted-acidic hydroxo ligand on the copper cation while the other developed at 350–400 °C is a Lewis-acidic coordinatively unsaturated Molybdenum Atom with a sulfur-deficient site. A nonstoichiometric sulfur-deficient neutral cluster Mo_6S_8− δ ( δ ≈ 0.4) also catalyzes the cracking reaction when activated at 400 °C.
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application of solid state Molybdenum sulfide clusters with an octahedral metal framework to catalysis ring opening of tetrahydrofuran to butyraldehyde
Journal of Cluster Science, 2013Co-Authors: Satoshi Kamiguchi, Sayoko Nagashima, Kazu Okumura, Kunio Takeda, Ryu Kajio, Teiji ChiharaAbstract:Solid-state Molybdenum sulfide clusters with an octahedral metal framework, the superconducting Chevrel phases, are applied to catalysis. The cluster of copper salt, Cu x Mo6S8 (x = 2.94), stored in air is treated in a hydrogen stream above 300 °C. The activated cluster exhibits catalytic activity for the ring-opening of tetrahydrofuran, yielding butyraldehyde. Cyclic ethers such as trimethylene oxide and tetrahydropyran are also converted to the corresponding aldehydes. The cluster contains nonstoichiometric defects of sulfur Atoms. Oxygen Atoms are incorporated at the sulfur-deficient sites upon storage in air, but they are removed from the sites by the activation in a hydrogen stream. The resulting coordinatively unsaturated Molybdenum Atoms are catalytically active for the ring-opening reaction. The Molybdenum Atom in an intermediate oxidation state around 2+ is moderately coordinated by the oxygen of tetrahydrofuran and favorably releases the produced aldehyde. The neutral cluster Mo6S8, which has such sulfur-deficient sites, also catalyzes the reaction.
Sayoko Nagashima - One of the best experts on this subject based on the ideXlab platform.
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solid state Molybdenum sulfide clusters with an octahedral metal framework as hydrogenation dehydrogenation and hydrogenolysis catalysts similar to the platinum group metals
Applied Catalysis A-general, 2015Co-Authors: Satoshi Kamiguchi, Sayoko Nagashima, Kazu Okumura, Kanako Arai, Hajime Iida, Teiji ChiharaAbstract:Abstract Solid-state Molybdenum sulfide clusters with a nonstoichiometric sulfur-deficient site, Cu x Mo 6 S 8− δ ( x = 2.94 and δ ≈ 0.3) and Mo 6 S 8– δ ( δ ≈ 0.4), catalyze the dehydrogenation of cyclohexene, the hydrogenation of alkyne, alkene, aldehyde, ketone, and nitrobenzene, and the hydrogenolysis of halogenobenzenes in a hydrogen stream above 300 °C. This catalytic behavior of the clusters is similar to that of the platinum group metals, which is attributable to the isoelectronicity of sulfur-coordinating Molybdenum Atom to the platinum group metals.
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Catalytic Cracking of Methyl tert-Butyl Ether to Isobutene over Brønsted and Lewis Acid Sites on Solid-state Molybdenum Sulfide Clusters with an Octahedral Metal Framework
Journal of Cluster Science, 2015Co-Authors: Satoshi Kamiguchi, Yasunari Seki, Akiharu Satake, Sayoko Nagashima, Kazu Okumura, Teiji ChiharaAbstract:Solid-state Molybdenum sulfide clusters with an octahedral metal framework, the Chevrel phases, are applied to the catalytic cracking of methyl tert -butyl ether (MTBE) to yield isobutene. The copper salt of the nonstoichiometric sulfur-deficient cluster, Cu_ x Mo_6S_8− δ ( x = 2.94 and δ ≈ 0.3), after storing in air, is thermally activated in a hydrogen stream, followed by the reaction with MTBE. Two kinds of catalytically active sites develop depending on the activation temperature: one developed at 100–200 °C is a Brønsted-acidic hydroxo ligand on the copper cation while the other developed at 350–400 °C is a Lewis-acidic coordinatively unsaturated Molybdenum Atom with a sulfur-deficient site. A nonstoichiometric sulfur-deficient neutral cluster Mo_6S_8− δ ( δ ≈ 0.4) also catalyzes the cracking reaction when activated at 400 °C.
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application of solid state Molybdenum sulfide clusters with an octahedral metal framework to catalysis ring opening of tetrahydrofuran to butyraldehyde
Journal of Cluster Science, 2013Co-Authors: Satoshi Kamiguchi, Sayoko Nagashima, Kazu Okumura, Kunio Takeda, Ryu Kajio, Teiji ChiharaAbstract:Solid-state Molybdenum sulfide clusters with an octahedral metal framework, the superconducting Chevrel phases, are applied to catalysis. The cluster of copper salt, Cu x Mo6S8 (x = 2.94), stored in air is treated in a hydrogen stream above 300 °C. The activated cluster exhibits catalytic activity for the ring-opening of tetrahydrofuran, yielding butyraldehyde. Cyclic ethers such as trimethylene oxide and tetrahydropyran are also converted to the corresponding aldehydes. The cluster contains nonstoichiometric defects of sulfur Atoms. Oxygen Atoms are incorporated at the sulfur-deficient sites upon storage in air, but they are removed from the sites by the activation in a hydrogen stream. The resulting coordinatively unsaturated Molybdenum Atoms are catalytically active for the ring-opening reaction. The Molybdenum Atom in an intermediate oxidation state around 2+ is moderately coordinated by the oxygen of tetrahydrofuran and favorably releases the produced aldehyde. The neutral cluster Mo6S8, which has such sulfur-deficient sites, also catalyzes the reaction.