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Start Over Author "Sato, Takafumi" Journal industrial & engineering chemistry research
15 results on '"Sato, Takafumi"'

5. Development of a Cs-Ru/CeO2Spherical Catalyst Prepared by Impregnation and Washing Processes for Low-Temperature Decomposition of NH3: Characterization and Kinetic Analysis Results

Author

Furusawa, Takeshi, Kuribara, Hiroki, Kimura, Koji, Sato, Takafumi, and Itoh, Naotsugu

Abstract

Cl-free Ru/CeO2spherical catalysts were prepared by incipient wetness impregnation and subsequent washing processes using RuCl3·3H2O and a commercial spherical CeO2support. Cs addition improved the catalytic performance for NH3decomposition, and the optimal Cs loading was a Cs/Ru molar ratio of 0.43. Transmission electron microscopy (TEM) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX) suggested that Cs was present around Ru metal particles and served as an anchor for forming small, well-dispersed Ru metal particles (∼2 nm). CO2temperature-programmed desorption results indicated that the Cs-Ru/CeO2catalyst had more strong basic sites than the Ru/CeO2catalyst. Kinetic analysis results clearly demonstrated that Cs addition promoted recombinative desorption of N atoms, which is the rate-determining step of NH3decomposition. Consequently, the Cs-Ru/CeO2spherical catalyst (Cs/Ru = 0.43) treated in Ar for 1 h at 773 K exhibited high catalytic activity for NH3decomposition (NH3conversion: 40% at 523 K and 80% at 573 K) at 2000 mL-NH3g cat–1h–1.

Published
2020
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8. Continuous Hydrothermal Synthesis of Nickel Ferrite Nanoparticles Using a Central Collision-Type Micromixer: Effects of Temperature, Residence Time, Metal Salt Molality, and NaOH Addition on Conversion, Particle Size, and Crystal Phase

Author

Sue, Kiwamu, primary, Aoki, Mitsuko, additional, Sato, Takafumi, additional, Nishio-Hamane, Daisuke, additional, Kawasaki, Shin-ichiro, additional, Hakuta, Yukiya, additional, Takebayashi, Yoshihiro, additional, Yoda, Satoshi, additional, Furuya, Takeshi, additional, Sato, Toshiyuki, additional, and Hiaki, Toshihiko, additional

Published
2011
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14. The Kinetics of the Incorporationof Metals into Tetraphenylporphyrinwith Metal Salts in High-Temperature Water.

Author

Sato, Takafumi, Ebisawa, Katsutoshi, Sue, Kiwamu, Ito, Satoshi, Takeru, Saito, and Itoh, Naotsugu

Subjects
*TETRAPHENYLPORPHYRIN, *SALTS, *HIGH temperatures, *WATER, *CHEMICAL kinetics, *SULFATES, *CHLORIDES, *TRANSITION metals
Abstract

The incorporation of cobalt, nickel, copper, and oxovanadium(IV)into nonpolar 5,10,15,20-tetraphenyl-21H,23H-porphyrin (H2TPP) occurred with their sulfates,nitrates, and chlorides in high-temperature water. The yield of metalloporphyrinsignificantly increased with increasing temperature for cobalt, nickel,and copper sulfates from 473 to 673 K, which means that the high temperatureregion was preferred for the incorporation of metals into the porphyrinstructure. In high-temperature water, most of H2TPP dissolved,whereas almost all of metals probably existed in solid phase. Theincorporation of metal into a porphyrin structure was almost first-orderwith respect to H2TPP and probably proceeded through thepre-equilibrium state between metal ion and H2TPP. [ABSTRACT FROM AUTHOR]

Published
2012
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15. Effect of Water Density on the Gasification of Lignin with Magnesium Oxide Supported Nickel Catalysts in Supercritical Water

Author

Sato, Takafumi, Furusawa, Takeshi, Ishiyama, Yasuyoshi, Sugito, Hirokazu, Miura, Yasutomo, Sato, Masahide, Suzuki, Noboru, and Itoh, Naotsugu

Abstract

Gasification of lignin biomass model compounds was examined in the presence of magnesium oxide supported nickel catalysts (Ni/MgO) in sub- and supercritical water from 523 to 673 K. The main gas products were methane, carbon dioxide, and hydrogen. The amount of gases produced increased with an increase in nickel loading on magnesium oxide. The highest total gas yield in a carbon basis was 78% with 20 wt % Ni/MgO catalyst at 673 K and 0.3 g/cm3water density. In this system, the metal and support of Ni/MgO probably play different roles in gasification that MgO decomposed lignin to reactive intermediates and nickel promoted reaction between intermediates and water to form gases. The yield of methane and carbon dioxide increased with increasing water density but then decreased and leveled out to constant values, which indicates that water density affected the reaction kinetics.

Published
2006
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