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Hideaki Hamada - One of the best experts on this subject based on the ideXlab platform.
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cooperative effect of platinum and alumina for the selective reduction of Nitrogen Monoxide with propane
Catalysis Letters, 1996Co-Authors: Megumu Inaba, Yoshiaki Kintaichi, Hideaki HamadaAbstract:Reduction of Nitrogen Monoxide with propane in the presence of oxygen proceeded not only on alumina-supported platinum but also on physical mixtures of alumina and silica-supported platinum, both of which are inactive for the selective NO reduction. Spillover, gas phase transfer of some reaction intermediates, or homogeneous propane oxidation seems responsible for the cooperative effect.
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High efficiency of alumina and H-zeolite catalysts for selective reduction of Nitrogen Monoxide by methanol in the presence of oxygen and water vapor
Applied Catalysis A-general, 1992Co-Authors: Hideaki Hamada, Yoshiaki Kintaichi, Motoi Sasaki, Tomohiro YoshinariAbstract:Abstract Alumina, Co/alumina, and H-ZSM-5 zeolite showed excellent catalytic activity for Nitrogen Monoxide reduction by methanol and ethanol at 300–400°C in the presence of high concentrations of oxygen and water vapor. Due to the inhibiting effect of water, propane, propene and 2-propanol did not reduce Nitrogen Monoxide effectively at such low temperatures over the alumina catalyst. Cu-ZSM-5 zeolite did not catalyze Nitrogen Monoxide reduction by methanol at all, whereas it showed activity for Nitrogen Monoxide reduction by ethanol.
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role of oxygen in selective reduction of Nitrogen Monoxide by propane over zeolite and alumina based catalysts
Catalysis Letters, 1992Co-Authors: Motoi Sasaki, Hideaki Hamada, Yoshiaki KintaichiAbstract:The role of coexisting oxygen in the selective reduction of Nitrogen Monoxide by propane on H-zeolites, alumina, Cu-ZSM-5 zeolite and Pt/Al2O3 catalysts was investigated. In the case of H-zeolites and alumina, oxidation of NO to NO2 played an important role for the overall selective reduction of NO. On the other hand, the initial reaction step was considered to be partial oxidation of propane over Cu-ZSM-5 and Pt/Al2O3.
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removal of Nitrogen Monoxide from exhaust gases through novel catalytic processes
Catalysis Today, 1991Co-Authors: Masakazu Iwamoto, Hideaki HamadaAbstract:Abstract The exhaust gas from vehicle engines and industrial boilers contains considerable amount of harmful Nitrogen Monoxide (NO) which causes air pollution and acid rain. To remove NO, at present, catalytic reduction processes using NH3 or CO have been applied, but several problems remain to be solved. It is widely accepted that catalytic decomposition is the best method for the removal of NO; however, the catalyst with consistently high activity for the reaction has never been found. In this paper the present position of decomposition catalysts is mentioned and the catalytic performance of copper ion-exchanged zeolites and Ag-Co3O4 oxides etc. is summarized based on the respective authors' results. A reaction mechanism of the decomposition is also proposed on the Cu-zeolites. In the last section the catalytic reduction of NO by hydrocarbons in the presence of oxygen, the newly developed catalytic process for removal of NO, has been introduced. The observations reported here suggest that the catalytic decomposition and/or reduction may be used in practice instead of the present reduction processes.
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transition metal promoted silica and alumina catalysts for the selective reduction of Nitrogen Monoxide with propane
Applied Catalysis, 1991Co-Authors: Hideaki Hamada, Yoshiaki Kintaichi, Motoi Sasaki, Mitsunori TabataAbstract:Abstract The effect of transition metal additives on the catalytic performances of silica and alumina was investigated for the selective reduction of Nitrogen Monoxide with propane in the presence of high concentrations of oxygen. Some metal-silica catalysts showed the activity although silica was quite inactive. Most of the transition metals were found to promote the catalytic activity of alumina, although the performances were dependent on the preparation conditions. In particular, metal-alumina catalysts containing metal aluminate showed excellent activity at low temperatures and under high space velocity conditions.
Yoshiaki Kintaichi - One of the best experts on this subject based on the ideXlab platform.
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cooperative effect of platinum and alumina for the selective reduction of Nitrogen Monoxide with propane
Catalysis Letters, 1996Co-Authors: Megumu Inaba, Yoshiaki Kintaichi, Hideaki HamadaAbstract:Reduction of Nitrogen Monoxide with propane in the presence of oxygen proceeded not only on alumina-supported platinum but also on physical mixtures of alumina and silica-supported platinum, both of which are inactive for the selective NO reduction. Spillover, gas phase transfer of some reaction intermediates, or homogeneous propane oxidation seems responsible for the cooperative effect.
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High efficiency of alumina and H-zeolite catalysts for selective reduction of Nitrogen Monoxide by methanol in the presence of oxygen and water vapor
Applied Catalysis A-general, 1992Co-Authors: Hideaki Hamada, Yoshiaki Kintaichi, Motoi Sasaki, Tomohiro YoshinariAbstract:Abstract Alumina, Co/alumina, and H-ZSM-5 zeolite showed excellent catalytic activity for Nitrogen Monoxide reduction by methanol and ethanol at 300–400°C in the presence of high concentrations of oxygen and water vapor. Due to the inhibiting effect of water, propane, propene and 2-propanol did not reduce Nitrogen Monoxide effectively at such low temperatures over the alumina catalyst. Cu-ZSM-5 zeolite did not catalyze Nitrogen Monoxide reduction by methanol at all, whereas it showed activity for Nitrogen Monoxide reduction by ethanol.
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role of oxygen in selective reduction of Nitrogen Monoxide by propane over zeolite and alumina based catalysts
Catalysis Letters, 1992Co-Authors: Motoi Sasaki, Hideaki Hamada, Yoshiaki KintaichiAbstract:The role of coexisting oxygen in the selective reduction of Nitrogen Monoxide by propane on H-zeolites, alumina, Cu-ZSM-5 zeolite and Pt/Al2O3 catalysts was investigated. In the case of H-zeolites and alumina, oxidation of NO to NO2 played an important role for the overall selective reduction of NO. On the other hand, the initial reaction step was considered to be partial oxidation of propane over Cu-ZSM-5 and Pt/Al2O3.
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transition metal promoted silica and alumina catalysts for the selective reduction of Nitrogen Monoxide with propane
Applied Catalysis, 1991Co-Authors: Hideaki Hamada, Yoshiaki Kintaichi, Motoi Sasaki, Mitsunori TabataAbstract:Abstract The effect of transition metal additives on the catalytic performances of silica and alumina was investigated for the selective reduction of Nitrogen Monoxide with propane in the presence of high concentrations of oxygen. Some metal-silica catalysts showed the activity although silica was quite inactive. Most of the transition metals were found to promote the catalytic activity of alumina, although the performances were dependent on the preparation conditions. In particular, metal-alumina catalysts containing metal aluminate showed excellent activity at low temperatures and under high space velocity conditions.
Kenneth D Karlin - One of the best experts on this subject based on the ideXlab platform.
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reductive coupling of Nitrogen Monoxide no facilitated by heme copper complexes
Inorganic Chemistry, 2010Co-Authors: Jun Wang, Mark P Schopfer, Amy A Sarjeant, Simona C Puiu, Kenneth D KarlinAbstract:The interactions of Nitrogen Monoxide (•NO; nitric oxide) with transition metal centers continue to be of great interest, in part due to their importance in biochemical processes. Here, we describe •NO(g) reductive coupling chemistry of possible relevance to that process (i.e., nitric oxide reductase (NOR) biochemistry), which occurs at the heme/Cu active site of cytochrome c oxidases (CcOs). In this report, heme/Cu/•NO(g) activity is studied using 1:1 ratios of heme and copper complex components, (F8)Fe (F8 = tetrakis(2,6-difluorophenyl)porphyrinate(2-)) and [(tmpa)CuI(MeCN)]+ (TMPA = tris(2-pyridylmethyl)amine). The starting point for heme chemistry is the mononitrosyl complex (F8)Fe(NO) (λmax = 399 (Soret), 541 nm in acetone). Variable-temperature 1H and 2H NMR spectra reveal a broad peak at δ = 6.05 ppm (pyrrole) at room temperature (RT), which gives rise to asymmetrically split pyrrole peaks at 9.12 and 8.54 ppm at −80 °C. A new heme dinitrosyl species, (F8)Fe(NO)2, obtained by bubbling (F8)Fe(NO) wi...
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carbon Monoxide and Nitrogen Monoxide ligand dynamics in synthetic heme and heme copper complex systems
Journal of the American Chemical Society, 2009Co-Authors: Heather R Lucas, Gerald J Meyer, Kenneth D KarlinAbstract:Intermolecular Nitrogen Monoxide (·NO) and carbon Monoxide (CO) transfer from iron to copper and back, a phenomenon not previously observed, has been accomplished by employing transient-absorbance laser flash photolysis methods. A 1:1 heme/copper component system consisting of a six-coordinate ferrous species, F8FeII(CO)(DCIM) or F8FeII(NO)(thf) [F8 = tetrakis(2,6-difluorophenyl)porphyrinate(2−); DCIM = 1,5-dicyclohexylimidazole; thf = tetrahydrofuran], and two ligand−copper(I) complexes, one with tridentate [BzL = (benzyl)bis(2-pyridylmethyl)amine] and one with tetradentate coordination [PyL = tris(2-pyridylmethyl)amine], was utilized. The results suggest a lower affinity for NO versus CO binding to copper(I) and a higher rate for NO versus CO binding to heme. In fact, the latter event has been observed in cytochrome c oxidase aa3.
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heme copper assembly mediated reductive coupling of Nitrogen Monoxide no
Journal of the American Chemical Society, 2009Co-Authors: Jun Wang, Mark P Schopfer, Amy A Sarjeant, Kenneth D KarlinAbstract:A iron-dinitrosyl species (6L)Fe(NO)2 (2), generated from Nitrogen Monoxide (·NO) binding to its related iron(II)-mononitrosyl complex (6L)Fe(NO) (1), efficiently effects reductive coupling of two ·NO molecules to release nitrous oxide (N2O), when Cu+ ion and 2 equiv acid are added; the heme/Cu product is [(6L)FeIII...CuII(D)]3+ (D = H2O or MeCN). In a control experiment where only (6L)Fe(NO)2 (2) is exposed to 2 equiv acid, no UV−vis change is observed; upon warming, ·NO(g) is released and (6L)Fe(NO) is reformed. The copper ion complex within the 6L ligand framework is required for the ·NO coupling chemistry. In a further control experiment Cu+ ion is added to (6L)Fe(NO)2 without acid present, [(6L)Fe(NO)...CuII(NO2−)]+ is obtained, with the amount of N2O(g) released fitting with copper(I) ion promoted disproportionation chemistry, 3·NO + ligand-CuI → N2O + ligand-CuII(NO2−). The chemical system described represents a (stoichiometric) functional model for heme/Cu protein nitric oxide reductase activity.
P J Millington - One of the best experts on this subject based on the ideXlab platform.
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mechanism of the selective reduction of Nitrogen Monoxide on platinum based catalysts in the presence of excess oxygen
Applied Catalysis B-environmental, 1994Co-Authors: R Burch, P J Millington, Andrew Peter WalkerAbstract:Abstract A range of alumina-supported platinum catalysts have been prepared and investigated for the selective reduction of Nitrogen Monoxide in the presence of a large excess of oxygen. Steady-state microreactor experiments have demonstrated that these catalysts are very active and selective for the reduction of Nitrogen Monoxide by propene at temperatures as low as 200°C. There does not appear to be a simple correlation between the activity for Nitrogen Monoxide reduction and the platinum surface area. Instead it is found that there is a very good inverse correlation between the maximum Nitrogen Monoxide reduction activity and the temperature. The most active catalysts for selective Nitrogen Monoxide reduction are those that generate activity at the lowest temperature. The technique of temporal analysis of products (TAP) has been used to obtain detailed mechanistic data about the selective Nitrogen Monoxide reduction reaction on an alumina-supported platinum catalyst. Using carbon Monoxide, hydrogen or propene as reductant it has been demonstrated that the predominant mechanism for selective Nitrogen Monoxide reduction involves the decomposition of Nitrogen Monoxide on reduced platinum metal sites, followed by the regeneration of the active platinum sites by the reductant. In the decomposition step it has been shown that oxygen from Nitrogen Monoxide is retained on the surface of the platinum and blocks the surface for further adsorption/reaction of Nitrogen Monoxide; it has been observed that oxidised platinum catalysts are not active for the Nitrogen Monoxide reduction reaction. Under typical operating conditions, propene is a far more efficient reductant than either carbon Monoxide or hydrogen. The greater efficiency of propene as a reductant is explained on the basis of the additional reducing power of the propene molecule, which can react with as many as nine adsorbed oxygen atoms, ensuring that 'patches' of reduced platinum are available for Nitrogen Monoxide adsorption/reaction. A small additional activity of reduced platinum in the presence of propene, which is not observed when carbon Monoxide or hydrogen is used as reductant, has been explained on the basis of a second mechanism involving the carbon-assisted decomposition of Nitrogen Monoxide at sites on the reduced platinum adjacent to adsorbed carbon-containing moieties, believed to be fragments from adsorbed propene molecules. A model for the selective reduction of Nitrogen Monoxide on alumina-supported platinum catalysts is presented which is capable of explaining all the results obtained in this work and in the published literature on this subject.
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role of propene in the selective reduction of Nitrogen Monoxide in copper exchanged zeolites
Applied Catalysis B-environmental, 1993Co-Authors: R Burch, P J MillingtonAbstract:Abstract Gas switching experiments, examining the first few minutes of reaction, have been used to study the selective reduction of Nitrogen Monoxide by propene on a Cu-ZSM-5 catalyst in an oxygen-rich gas mixture. It has been found that the conversion of Nitrogen Monoxide to Nitrogen reaches a steady-state activity in a very short period of time. It is concluded that carbon deposition is not responsible for the conversion of Nitrogen Monoxide into Nitrogen. It is proposed instead that the hydrocarbon and oxygen act to maintain the active copper sites in an oxidation state suitable for direct Nitrogen Monoxide decomposition.
Tsugio Sato - One of the best experts on this subject based on the ideXlab platform.
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Photocatalytic activity of silicon-based nanoflakes for the decomposition of Nitrogen Monoxide.
Dalton Transactions, 2017Co-Authors: Hiroshi Itahara, Xiaoyong Wu, Haruo Imagawa, Kazunobu Kojima, Shigefusa F. Chichibu, Tsugio SatoAbstract:The photocatalytic decomposition of Nitrogen Monoxide (NO) was achieved for the first time using Si-based nanomaterials. Nanocomposite powders composed of Si nanoflakes and metallic particles (Ni and Ni3Si) were synthesized using a simple one-pot reaction of layered CaSi2 and NiCl2. The synthesized nanocomposites have a wide optical absorption band from the visible to the ultraviolet. Under the assumption of a direct transition, the photoabsorption behavior is well described and an absorption edge of ca. 1.8 eV is indicated. Conventional Si and SiO powders with indirect absorption edges of 1.1 and 1.4 eV, respectively, exhibit considerably low photocatalytic activities for NO decomposition. In contrast, the synthesized nanocomposites exhibited photocatalytic activities under irradiation with light at wavelengths >290 nm (
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photocatalytic activity of silicon based nanoflakes for the decomposition of Nitrogen Monoxide
Dalton Transactions, 2017Co-Authors: Hiroshi Itahara, Xiaoyong Wu, Haruo Imagawa, Kazunobu Kojima, Shigefusa F. Chichibu, Tsugio SatoAbstract:The photocatalytic decomposition of Nitrogen Monoxide (NO) was achieved for the first time using Si-based nanomaterials. Nanocomposite powders composed of Si nanoflakes and metallic particles (Ni and Ni3Si) were synthesized using a simple one-pot reaction of layered CaSi2 and NiCl2. The synthesized nanocomposites have a wide optical absorption band from the visible to the ultraviolet. Under the assumption of a direct transition, the photoabsorption behavior is well described and an absorption edge of ca. 1.8 eV is indicated. Conventional Si and SiO powders with indirect absorption edges of 1.1 and 1.4 eV, respectively, exhibit considerably low photocatalytic activities for NO decomposition. In contrast, the synthesized nanocomposites exhibited photocatalytic activities under irradiation with light at wavelengths >290 nm (<4.28 eV). The photocatalytic activities of the nanocomposites were confirmed to be constant and did not degrade with the light irradiation time.
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hierarchical zno nanostructures controlling the synthesis and photocatalytic decomposition of Nitrogen Monoxide
RSC Advances, 2013Co-Authors: Tsugio Sato, Quang Duc Truong, Thi Hang Le, Takeshi Kimura, Yongchien LingAbstract:Hierarchical metal oxide nanostructures that possess unique chemical and physical properties have attracted widespread interest recently because of their potential applications in catalysis, biological engineering, and photoelectronic devices. Herein, hierarchical ZnO nanostructures (ZONS) with unique structural features such as dumbbells, twin-prisms, whiskers, and nanorod bundles have been fabricated using a facile hydrothermal method with lysine as an in situ source of OH− and structure-directing agent. The effect of the lysine amount on structural features was systematically investigated, in order to elucidate the roles of lysine in the growth process. It was found that lysine plays an important role in controlling the shape and assembly of the hierarchical structures of ZONS using its capping and chelating abilities. The photocatalytic activities of different ZONS were evaluated using the photocatalytic decomposition of Nitrogen Monoxide. The decomposition properties were found to be strongly dependent on the surface area and the assembled features of the structure.