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1. Catalytic partial oxidation of methane over oxide-ion-conductive lanthanum silicate apatites.

Author

Pamungkas, Afif, Goto, Yuta, Murata, Kazumasa, Hosokawa, Saburo, Ogawa, Satoshi, Ohishi, Kosaku, Matsumoto, Tomohiro, Saito, Miwa, and Motohashi, Teruki

Subjects
KINETIC isotope effects, SYNTHESIS gas, CATALYTIC activity, CATALYTIC oxidation, IONIC structure
Abstract

A lanthanum silicate La9.33Si6O26 (LSO) crystallizes in an apatite-type structure and has been known as a promising oxide-ion conductor. Here, we report the activity of LSO for catalytic partial oxidation of methane (CPOX) to synthesis gas. The LSO catalyst demonstrated relatively high catalytic activity from 500 to 700 °C, with CH4 conversion reaching 22.1% at 700 °C while retaining moderate CO and H2 selectivities of 20–60%. Notably, LSO exhibited higher CPOX activity than non-apatite-type La2SiO5 despite their similar specific surface areas. The higher CPOX activity of LSO is likely attributed to its structural superiority involving mobile oxide ions in the crystal structure. The reaction kinetic study showed that the reaction orders for methane and oxygen in the CPOX reaction over the LSO catalyst were 0.69–0.73 and 0.08–0.21, respectively. Furthermore, the small contribution of adsorbed O species generated from gas-phase O2 molecules indicated that the lattice oxygen may be involved in the reaction mechanism. The kinetic isotope effect (KIE) study using a CD4 suggested that C–H bond breaking is the rate-determining step of CPOX over LSO. [ABSTRACT FROM AUTHOR]

Published
2024
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3. A rice gene that confers broad-spectrum resistance to β-triketone herbicides

Author

Maeda, Hideo, Murata, Kazumasa, Sakuma, Nozomi, Takei, Satomi, Yamazaki, Akihiko, Karim, Md. Rezaul, Kawata, Motoshige, Hirose, Sakiko, Kawagishi-Kobayashi, Makiko, Taniguchi, Yojiro, Suzuki, Satoru, Sekino, Keisuke, Ohshima, Masahiro, Kato, Hiroshi, Yoshida, Hitoshi, and Tozawa, Yuzuru

Published
2019

6. 4th Conference of Cereal Biotechnology and Breeding jointly organized by EUCARPIA Cereal Section November 6–9, 2017 • Budapest, Hungary : BOOK OF ABSTRACTS

Author

Consortium INEW, PPP Barley Consortium, Börner, Andreas, Nagel, Manuela, Tarawneh, Rasha, Arif, Mian Abdur Rehman, Agacka-Mołdoch, Monika, Börner, Mariann, Lohwasser, Ulrike, Rieweach, David, Wieb, Janine, Altmann, Thomas, Góralska, Magdalena, Lenarczyk-Puri, Natalia, Podgórska, Katarzyna, Berdzik, Marcin, Stojałowski, Stefan, Myśków, Beata, Kiss, Tibor, Veisz, Ottó, Karsai, Ildikó, Martín, Antonio, Rasmussen, Søren K., Legzdina, Linda, Fan, Weiyao, Tikhenko, Natalia, Rutten, Twan, Senula, Angelika, Rubtsova, Myroslava, Keller, E. R. Joachim, Vitányi, Beáta, Nagy, Katalin, Fekete, Anna Katalin, Dudás, Brigitta, Lantos, Csaba, Pauk, János, Jenes, Barnabás, Yu, Bianyun, Zhang, Wentao, Gao, Peng, Sidebottom, Christine, Lokuruge, Prabhath, Polley, Brittany, Clarke, Carling, Sharpe, Andrew, Knox, Ron, Cuthbert, Richard, Ruan, Yuefeng, Pozniak, Curtis J., Fobert, Pierre, Dziurka, Kinga, Noga, Angelika, Marcińska, Izabela, Czyczyło-Mysza, Ilona, Warchoł, Marzena, Kapłoniak, Kamila, Warzecha, Tomasz, Sutkowska, Agnieszka, Werwińska, Krystyna, Nita, Zygmunt, Skrzypek, Edyta, Fradgley, Nick, Bentley, Alison, Gardner, Keith, Howell, Phil, Mackay, Ian, Scott, Mike, Mott, Richard, Cockram, James, Galani, Saddia, Sahar, Shagufta, Musharraf, Syed Ghulam, Azhar, Abid, Ferjaoui, Sahbi, Bouslimi, Chadha, Udupa, Sripada M., Hamza, Sonia, Mariana, Ittu, Ciuca, Matilda, Marinciu, Cristina, Cristina, Daniel, Turcu, Alina, Mandea, Vasile, Ittu, Gheorghe, Jabłoński, Bartosz, Onyśk, Agnieszka, Wyszyńska, Renata, Boczkowska, Maja, Przyborowski, Mateusz, Gasparis, Sebastian, Orczyk, Wacław, Nadolska-Orczyk, Anna, Bińkowski, Jan, Kubiś, Jakub, Pogorzelska, Katarzyna, Pellny, Till K, Bolibok-Brągoszewska, Hanna, Idziak-Helmcke, Dominika, Rojek, Magdalena, Hosiawa-Barańska, Marta, Tsai, Hsin-Yuan, Cericola, Fabio, Edriss, Vahid, Andersen, Jeppe, Orabi, Jihad, Jensen, Jens, Jahoor, Ahmed, Janss, Luc, Jensen, Just, Lawrenson, Tom, Hayta, Sadiye, Smedley, Mark, Hinchliffe, Alison, Harwood, Wendy, Gimenez, Guillermo G., Barakate, Abdellah, Russell, Joanne, Stephens, Jennifer, Lampugnani, Edwin R., Doblin, Monika S., Fincher, Geoffrey B., Burton, Rachel A., Waugh, Robbie, Tucker, Matthew, Houston, Kelly, Jouanin, Aurelie, Leigh, Fiona, Wallington, Emma, Schaart, Jan, Smulders, Marinus J.M., Kała, Maciej, Kim, Sung-Yong, Brueggeman, Robert, Åhman, Inger, Zhu, Li-Hua, Bouchet, Sophie, Lemarié, Stéphane, Fugeray-Scarbel, Aline, Auzanneau, Jérôme, Charmet, Gilles, Ali, Ahmad, Mastrangelo, Anna Maria, De Vita, Pasquale, Laido, Giovanni, Marone, Daniale, Arshad, Muhammad, Naqvi, S.M. Sawlan, Sher, Hassan, Rasheed, Awais, Kazi, Abdul Mujeeb, Oakey, Helena, Bayer, Micha, Macaulay, Malcolm, Byrt, Caitlin, Gilliham, Matthew, Salt, David E, István, Monostori, Fruzsina, Szira, Alessandro, Tondelli, Tamás, Árendás, Krisztián, Gierczik, Luigi, Cattivelli, Gábor, Galiba, Attila, Vágújfalvi, Bakuma, Alla, Chebotar, Galyna, Filimonov, Vadim, Kyrylyuk, Tetyana, Chebotar, Sabina, Kristensen, Peter Skov, Andersen, Jeppe Reitan, Guzmán, Carlos, Schurr, Ulrich, Pieruschka, Roland, Neumann, Kerstin, Zhao, Yusheng, Dhanagond, Sidram, Reif, Jochen C., Graner, Andreas, Raymaekers, Dries, Taylor, Mike, Åhman, Inger M., Crespo-Herrera, Leonardo A., Kobiljski, Borislav, Mladenović, Gojko, Jestrović, Zorica, Jancsó, Mihály, Ács, Katalin, Bóna, Lajos, Purgel, Szandra, Békés, Ferenc, Schwember, A.R., Matus, I., Sharma, Dew Kumari, Rosenqvist, Eva, Carl-Otto-Ottosen, Torp, Anna Maria, Andersen, Sven Bode, El-Haddoury, Jamal, Henkrar, Fatima, Grana, Zahra, Nyiraguhirwa, Solange, Gyawali, Sanjaya, Verma, Ramesh, Ouabbou, Hassan, Ibriz, Mohammed, Iraqi, Driss, Forgeois, Paul, Grausgruber, Heinrich, Cuendet, Catherine, Dell’Avo, Franca, Koppel, Reine, Weyermann, Verena, Mikó, Péter, Vida, Gyula, Rakszegi, Marianna, Lafferty, Julia, Lorentz, Bruno, Longin, Carl Friedrich Horst, Megyeri, Mária, Kaskarbayev, Zheksenbay, Zhloba, Ludmila, Kiyas, Aldabergen, Kunanbayev, Kairat, Churkina, Galina, Zueva, Nataliya, Cattivelli, Luigi, Guerra, Davide, Tondelli, Alessandro, Bustos-Korts, D., Rizza, Fulvia, Bretani, Gianluca, Ferrandi, Chiara, Lazzari, Barbara, Rossini, Laura, Ozkan, Hakan, Molnar-Lang, Marta, van Eeuwijk, Fred, Dawson, Ian K, Fricano, Agostino, Azad, Md. Abul Kalam, Kamruzzaman, Md., Yasmine, Fahmina, Islam, Mirza Mofazzal, Jankuloski, Ljupcho, Christopher, John (Jack), Anzooman, Monia, Menzies, Neal, Dalal, Ram, Dang, Yash, Novák, Aliz, Boldizsár, Ákos, Gierczik, Krisztián, Mohamed, Ahres, Ádám, Éva, Bognár, László Kozma, Vágújfalvi, Attila, Båga, Monica, Chibbar, Ravindra, Galiba, Gábor, Gottwald, Sven, Bhandari, Dhaka Ram, Wang, Qing, Li, Bin, Römpp, Andreas, Friedt, Wolfgang, Spengler, Bernhard, Jäger, Katalin, Sáfrán, Eszter, Fábián, Attila, Deák, Csilla, Papp, István, Barnabás, Beáta, Mesterhazy, Akos, Varga, Mónika, Bartók, Tibor, Lehoczki-Krjak, Szabolcs, Toth, Beata, Miloud, Hafsi, Pál, Magda, Szalai, Gabriella, Janda, Tibor, Molnár, István, Lovegrove, Alison, Darkó, Éva, Farkas, András, Láng, László, Bedő, Zoltán, Doležel, Jaroslav, Molnár-Láng, Márta, Shewry, Peter, Tiryakioğlu, Murat, Sakallı, Abdulla, Alloudane, Rajae, El Mourabit, Nourdin, Barrijal, Said, Bengtsson, Therése, Manninen, Outi, Bulatova, Kulpash, Mazkirat, Shynar, Babissekova, Dilyara, Aytimbetova, Klara, Goncharova, Anastasiya, Lavrinenko, Yuriy, Bazaliy, Galyna, Cope, Jonathan, Norton, Gareth, George, Timothy, Newton, Adrian, Császár, Orsolya, Lajos, Károly, Szalai, Márk, Dziurka, Michał, Dashkevich, Svetlana, Utebayev, Maral, Chilimova, Irina, Babkenov, Adilchan, Akhmetova, Galiya, Chaimae, Senhaji, Khadija, Ahansal, Rabha, Abdelwahd, Allal, Douira, Driss, Iraqi, Gracz, Joanna, Karłowski, Wojciech, Kuczyński, Jakub, Tyczewska, Agata, Haberle, Jan, Svoboda, Pavel, Neumannová, Adéla, Kurešová, Gabriela, Raimanová, Ivana, Holková, Ludmila, Solařová, Eva, Bradáčová, Marta, Smutná, Pavlína, Horčička, P., Pospíšilová, V., Veškrna, O., Bížova, I., Chrpova, J., Sumíková, T., Ittu, Mariana, Marinciu, Cristina Mihaela, Voica, Maria, Banateanu, Cecilia, Mayer, Marianna, Karsai, Idikó, Mirosavljević, Milan, Momčilović, Vojislava, Mikić, Sanja, Trkulja, Dragana, Denčić, Srbislav, Jocković, Bojan, Aćin, Vladimir, Pržulj, Novo, Nakhoda, Babak, Mohammadi-Nejad, Ghasem, Mardi, Mohsen, Amini, Ashkboos, Tabatabaei, Mohammad-Taghi, Parsayev, Evgeniy, Filippova, Nadezhda, Permana, Hadian, Ishii, Kazuo, Murata, Kazumasa, Yamada, Tetsuya, Kanekatsu, Motoki, Prokesova, Lenka, Smutna, Pavlina, Holkova, Ludmila, Rukavitsina, Irina, Suleimenov, Mechlis, Yerpasheva, Dana, Shtefan, Galina, Ivanova, Galina, Ferderer, Ella, Kalapos, Balázs, Ahres, Mohamed, Székely, András, Gulyás, Zsolt, Kovács, Kristóf, Jones, Huw D, Dalmay, Tamás, Soltész, Alexandra, Trávníčková, Martina, Chrpová, Jana, Martinek, Petr, Hnilička, František, Żywicki, Marek, Twardowski, Tomasz, Végh, Balázs, Marček, Tihana, Wiśniewska, Halina, Kwiatek, Michał, Majka, Maciej, Gawłowska, Magdalena, Korbas, Marek, Danielewicz, Jakub, Belter, Jolanta, Bilgrami, Sayedeh Saba, Sichani, Jalal Sabouri, Zandi, Peiman, Zhunusbayeva, Zhazira, Omirbekova, Nargul, Zhussupova, Aizhan, Mursalieva, Valentina, Nam, Svetlana, Żur, Iwona, Surówka, Ewa, Dubas, Ewa, Nowicka, Anna, Krzewska, Monika, Hura, Tomasz, Rapacz, Marcin, Wójcik-Jagła, Magdalena, Ostrowska, Agnieszka, Malaga, Sabina, Janowiak, Franciszek, Pellny, Till, Patil, Archana, Freeman, Jackie, Plummer, Amy, Hess, Linde, Phillips, Andy, Berry, Simon, Mitchell, Rowan, Larkin, Philip, Tanner, Gregory, Colgrave, Michelle, Blundell, Malcolm, Howitt, Crispin, Morita, Naofumi, Van Hung, Pham, Cegiełko, Małgorzata, Kiecana, Irena, Mielniczuk, Elżbieta, Pastucha, Alina, Perkowski, Juliusz, Áy, Zoltán, Czirle, Csaba, Palágyi, András, Mihály, Róbert, Vermeulen, Philippe, Suman, Michele, Pierna, Juan Antonio Fernández, and Baeten, Vincent

Published
2017

8. Alleles of high-yielding indica rice that improve root hydraulic conductance also increase flag leaf photosynthesis, biomass, and grain production of japonica rice in the paddy field

Author

Yamashita, Masahiro, primary, Ootsuka, Chikako, additional, Kubota, Hikaru, additional, Adachi, Shunsuke, additional, Yamaguchi, Takuya, additional, Murata, Kazumasa, additional, Yamamoto, Toshio, additional, Ueda, Tadamasa, additional, Ookawa, Taiichiro, additional, and Hirasawa, Tadashi, additional

Published
2022
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11. Active site for syngas production by direct partial oxidation of CH4over ZrO2Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d4cy00187g

Author

Murata, Kazumasa, Arai, Keita, Kondo, Nao, Manabe, Ryo, Yumura, Takashi, and Hosokawa, Saburo

Abstract

The production of high-value-added chemicals and their raw materials by partial oxidation of methane (POM) is advantageous. The screening of 31 simple oxide catalysts for direct POM showed that ZrO2had the highest syngas yield (CO and H2) and was thus a promising catalyst. Kinetic analysis indicated that POM over the ZrO2catalyst proceeded in a Langmuir–Hinshelwood mechanism and that CH4activation was the rate-limiting step. Density functional theory calculations showed that CH4was activated on coordinatively unsaturated Zr4+cations formed by the dehydration of the hydroxyl groups on the ZrO2surface. In situdiffuse reflectance infrared Fourier transform spectroscopy revealed that CH4was converted into CO and H2through CH4-oxygenated intermediates, such as methoxy and formate species. The CH4-oxygenated intermediates on the ZrO2catalyst were closely related to the catalytic performance of the oxide catalysts in POM. A comprehensive investigation of the POM reaction over ZrO2-based catalysts was then conducted. ZrO2modification with tungsten oxide (WOx) or lanthanum oxide (LaOx) was examined to determine their ability to improve the catalytic properties of ZrO2for POM. ZrO2modification with WOxand LaOxenhanced its acidity and basicity, respectively. CO selectivity was increased by modifying ZrO2with a small amount of WOx. Moreover, modification with LaOxincreased CH4conversion and H2yield at low temperatures.

Published
2024
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12. Structure–Property Relationships of Pt–Sn Nanoparticles Supported on Al2O3 for the Dehydrogenation of Methylcyclohexane

Author

Murata, Kazumasa, Kurimoto, Natsuki, Yamamoto, Yuta, Oda, Akira, Ohyama, Junya, and Satsuma, Atsushi

Subjects
methylcyclohexane, dehydrogenation, nanoparticle, alloy, local structure, Pt−Sn catalyst
Abstract

The structure–catalytic property relationships of Al2O3-supported Pt–Sn nanoparticles (Pt–Sn/Al2O3) in the dehydrogenation of methylcyclohexane (MCH) were investigated by varying the Sn/Pt ratios of the catalysts. The initial activity and the deactivation rate of the Pt–Sn/Al2O3 catalysts in the MCH dehydrogenation decreased in line with an increase in the Sn/Pt ratio from 0 to 3. The Pt–Sn/Al2O3 catalyst with a Sn/Pt ratio of 2 showed good activity, durability, and toluene selectivity in the MCH dehydrogenation among the series of catalysts. The dispersion of Pt in the Pt–Sn/Al2O3 catalysts was observed to decrease with an increase in the Sn/Pt ratio. Structural changes in the catalysts from Pt–Sn clusters to intermetallic Pt3Sn and PtSn nanoparticles were also observed using scanning transmission electron microscopy and X-ray diffraction. According to structural analysis using X-ray absorption fine-structure spectroscopy and infrared spectroscopy using carbon monoxide as a probe, the electron density of Pt increased, and the fraction of Pt–Pt adjacent sites decreased with an increase in the Sn/Pt ratio. Comparing the catalytic properties and the structures of the Pt–Sn/Al2O3 catalysts, their initial activities were correlated with the dispersion of Pt. In addition, the durability and selectivity of the catalysts were enhanced due to an increase in the electron density of Pt and a decrease in the number of Pt–Pt adjacent sites. Overall, the properties of the catalysts in the MCH dehydrogenation are determined by the local structure of Pt atoms rather than the crystal structure of the Pt–Sn alloy nanoparticles on Al2O3.

Published
2021

14. Relationship between penta-coordinated Al^3+ sites in the Al2O3 supports and CH4 combustion activity of Pd/Al2O3 catalysts

Author

Murata, Kazumasa, Shiotani, Takumi, Ohyama, Junya, Wakabayashi, Ryutaro, Maruoka, Hirokazu, Kimura, Tatsuo, and Satsuma, Atsushi

Abstract

Pd/Al2O3 catalysts were prepared using various Al2O3 supports with different structural features such as crystalline phase and crystallinity related to Al^3+ coordination, revealing a significant insight into the methane (CH4) combustion activity of Pd nanoparticles with the fraction of penta-coordinated Al^3+ sites in the Al2O3 supports.

Published
2021

15. Kinetic analysis of Ag particle redispersion into ZSM-5 in the presence of coke using in situ XAFS

Author

Murata, Kazumasa, Ohyama, Junya, and Satsuma, Atsushi

Abstract

In the present study, the redispersion behavior of Ag particles on ZSM-5 in the presence of coke was observed using in situ X-ray absorption fine structure (XAFS) spectroscopy. The dynamics of Ag particle redispersion into the ZSM-5 pores were evaluated by linear combination fitting (LCF) of the X-ray absorption near edge structure (XANES) spectra. In addition, the behavior of coke combustion in Ag-ZSM-5 was observed by thermogravimetric analysis (TGA). The rate constant of Ag particle redispersion was smaller than that of coke combustion at ≥500 °C, but it was three times larger than that of coke combustion at

Published
2021

17. Tuning the oxygen release properties of CeO2-based catalysts by metal–support interactions for improved gasoline soot combustion

Author

Ashikaga, Ryota, Murata, Kazumasa, Ito, Tetsuya, Yamamoto, Yuta, Arai, Shigeo, and Satsuma, Atsushi

Abstract

To develop highly active soot combustion catalysts for gasoline direct injection exhausts under low oxygen concentration conditions, CeO2 supported-metal catalysts (M/CeO2, M = Mn, Fe, Co, Ni, Cu, Rh, Pd, and Ag) were examined. Among the catalysts tested, Cu/CeO2 and Rh/CeO2 displayed the highest soot combustion activity. By comparing the activities of Cu-based catalysts with and without a Cu–CeO2 interface, the importance of such an interface for soot combustion was inferred. The oxygen release rate of CeO2-based catalysts, enhanced by metal–CeO2 interactions, was indicated as the controlling factor of catalytic activity. The soot oxidation activity and oxygen release rate were also demonstrated to correlate with metal–oxygen bond energy. Based on the redox properties and structural characteristics of CeO2-based catalysts, loading CeO2 with Cu or Rh, which have moderate M–O bond energy, was concluded to be optimal both in terms of the dispersion of supported-metal species and reducibility of the CeO2-based catalyst.

Published
2020

18. Methane Combustion over Pd/Al2O3 Catalysts in the Presence of Water: Effects of Pd Particle Size and Alumina Crystalline Phase

Author

Murata, Kazumasa, Ohyama, Junya, Yamamoto, Yuta, Arai, Shigeo, and Satsuma, Atsushi

Subjects
methane combustion, crystalline phase, Pd catalyst, particle size, alumina
Abstract

The effects of the Pd particle size and the Al2O3 crystalline phase of Pd/Al2O3 catalysts on the CH4 combustion in the presence of H2O were investigated. According to X-ray absorption fine structure (XAFS) measurements, it was revealed that, during the CH4 combustion, the Pd nanoparticles existed on the Al2O3 support as a PdO phase, while the crystallinity of PdO depended on the Pd particle size. On the basis of X-ray diffraction (XRD), amorphous PdO particles with a size of 7 nm) were formed, which were highly active for CH4 combustion. Comparing the effects of the different Al2O3 crystalline phases, Pd/α-Al2O3 was proved to be more resistant to deactivation by H2O than Pd/γ-Al2O3 and Pd/θ-Al2O3. Moreover, according to H2O temperature-programmed desorption (TPD) and infrared (IR) measurements, since α-Al2O3 was relatively hydrophobic compared to γ-Al2O3 and θ-Al2O3, a faster and reversible adsorption/desorption of OH/H2O species was achieved, while the H2O poisoning on PdO species in the vicinity was limited., ファイル公開：2021-08-07

Published
2020

19. Kinetic analysis of Ag particle redispersion into ZSM-5 in the presence of coke using in situ XAFS

Author

Murata, Kazumasa, Ohyama, Junya, Satsuma, Atsushi, Murata, Kazumasa, Ohyama, Junya, and Satsuma, Atsushi

Abstract

In the present study, the redispersion behavior of Ag particles on ZSM-5 in the presence of coke was observed using in situ X-ray absorption fine structure (XAFS) spectroscopy. The dynamics of Ag particle redispersion into the ZSM-5 pores were evaluated by linear combination fitting (LCF) of the X-ray absorption near edge structure (XANES) spectra. In addition, the behavior of coke combustion in Ag-ZSM-5 was observed by thermogravimetric analysis (TGA). The rate constant of Ag particle redispersion was smaller than that of coke combustion at ≥500 °C, but it was three times larger than that of coke combustion at <500 °C. According to 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR), the Ag+ ions in the ZSM-5 pores improved the hydrothermal stability of Ag-ZSM-5. Therefore, a two-step regeneration process, in which the Ag particle redispersion proceeded first at low temperature (<500 °C) followed by a complete combustion of the coke at high temperature (≥500 °C) to prolong the catalyst lifetime, was used.

Published
2022

20. Relationship between penta-coordinated Al^3+ sites in the Al2O3 supports and CH4 combustion activity of Pd/Al2O3 catalysts

Author

Murata, Kazumasa, Shiotani, Takumi, Ohyama, Junya, Wakabayashi, Ryutaro, Maruoka, Hirokazu, Kimura, Tatsuo, Satsuma, Atsushi, Murata, Kazumasa, Shiotani, Takumi, Ohyama, Junya, Wakabayashi, Ryutaro, Maruoka, Hirokazu, Kimura, Tatsuo, and Satsuma, Atsushi

Abstract

Pd/Al2O3 catalysts were prepared using various Al2O3 supports with different structural features such as crystalline phase and crystallinity related to Al^3+ coordination, revealing a significant insight into the methane (CH4) combustion activity of Pd nanoparticles with the fraction of penta-coordinated Al^3+ sites in the Al2O3 supports.

Published
2022

21. Structure–Property Relationships of Pt–Sn Nanoparticles Supported on Al2O3 for the Dehydrogenation of Methylcyclohexane

Author

Murata, Kazumasa, Kurimoto, Natsuki, Yamamoto, Yuta, Oda, Akira, Ohyama, Junya, Satsuma, Atsushi, Murata, Kazumasa, Kurimoto, Natsuki, Yamamoto, Yuta, Oda, Akira, Ohyama, Junya, and Satsuma, Atsushi

Abstract

The structure–catalytic property relationships of Al2O3-supported Pt–Sn nanoparticles (Pt–Sn/Al2O3) in the dehydrogenation of methylcyclohexane (MCH) were investigated by varying the Sn/Pt ratios of the catalysts. The initial activity and the deactivation rate of the Pt–Sn/Al2O3 catalysts in the MCH dehydrogenation decreased in line with an increase in the Sn/Pt ratio from 0 to 3. The Pt–Sn/Al2O3 catalyst with a Sn/Pt ratio of 2 showed good activity, durability, and toluene selectivity in the MCH dehydrogenation among the series of catalysts. The dispersion of Pt in the Pt–Sn/Al2O3 catalysts was observed to decrease with an increase in the Sn/Pt ratio. Structural changes in the catalysts from Pt–Sn clusters to intermetallic Pt3Sn and PtSn nanoparticles were also observed using scanning transmission electron microscopy and X-ray diffraction. According to structural analysis using X-ray absorption fine-structure spectroscopy and infrared spectroscopy using carbon monoxide as a probe, the electron density of Pt increased, and the fraction of Pt–Pt adjacent sites decreased with an increase in the Sn/Pt ratio. Comparing the catalytic properties and the structures of the Pt–Sn/Al2O3 catalysts, their initial activities were correlated with the dispersion of Pt. In addition, the durability and selectivity of the catalysts were enhanced due to an increase in the electron density of Pt and a decrease in the number of Pt–Pt adjacent sites. Overall, the properties of the catalysts in the MCH dehydrogenation are determined by the local structure of Pt atoms rather than the crystal structure of the Pt–Sn alloy nanoparticles on Al2O3.

Published
2022

22. Unveiling Static and Dynamic Structures of Pd Clusters Influenced by Al2O3Surfaces: DFT and AIMD Studies

Author

Murata, Kazumasa, Oda, Akira, Satsuma, Atsushi, and Sawabe, Kyoichi

Abstract

Metal nanoparticles (MNPs) supported on oxides are used in various catalytic reactions, such as petrochemical processes and exhaust gas purification. Metal–support interactions (MSIs) between MNPs and oxides affect the morphology and thermal stability of the MNPs, which are known to be related to the catalytic activity of the MNPs. However, the effect of MSIs is still a matter of debate. We conducted density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) to investigate the geometric structure and migration behavior of Pd clusters on various Al2O3surfaces. The MSIs of the Pd clusters with different Al2O3surfaces resulted in different morphologies of the clusters. The shape of Pd clusters on α-Al2O3(0001) were deformed to oblate and on γ-Al2O3(110) to prolate. On the other hand, the shape of Pd clusters on γ-Al2O3(100) did not change from that in a vacuum. The migration rate of Pd clusters was also affected by the MSI, which was higher on γ-Al2O3(110) than on α-Al2O3(0001) and γ-Al2O3(100). To evaluate the interactions between Pd clusters and Al2O3surfaces, we calculated the interaction energies for Pd clusters with various sizes on Al2O3surfaces. The interaction energy of Pd/Al2O3systems depended on the coordination number (CN, number of bonds per Pd atom) of Pd–Al and Pd–O. Despite the smaller atomic density of Al and O of the γ-Al2O3(110) surface than that of α-Al2O3(0001) and γ-Al2O3(100) surfaces, the number of bonds formed between Pd clusters and γ-Al2O3(110) was greater than that of α-Al2O3(0001) and γ-Al2O3(100). According to AIMD simulations and perpendicular displacements of Al and O atoms bound to the Pd cluster on the Al2O3surface from the bare Al2O3surface, coordinatively unsaturated Al3+sites on γ-Al2O3(110) were more flexible than those on α-Al2O3(0001) and γ-Al2O3(100). The flexibility of γ-Al2O3(110) facilitated the formation of bonds with the Pd cluster, resulting in stronger MSIs. When the coordinatively unsaturated Al3+sites were hydrated, the MSIs were found to be weakened.

Published
2023
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27. Identification of active sites in CO oxidation over a Pd/Al2O3 catalyst

Author

Murata, Kazumasa, Eleeda, Eleen, Ohyama, Junya, Yamamoto, Yuta, Arai, Shigeo, and Satsuma, Atsushi

Subjects
Pd catalyst, particle size effect, CO oxidation, alumina, surface structure, metal-support interaction
Abstract

The active sites of Pd/Al2O3 catalysts for CO oxidations were identified by investigating the dependence of CO oxidation activities on the surface structure and morphology of Pd nanoparticles. The maximum catalytic activity was obtained for Pd particles approximately 2 nm in particle size. We performed structural analyses on the Pd surface through infrared (IR) spectroscopy of the adsorbed CO molecules. A positive correlation was obtained between catalytic activity and the fraction of linear CO adsorbed on Pd corner sites and Pd(111) facets, indicating that these sites are highly active for CO oxidation. X-ray absorption fine structure (XAFS) and spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) measurements demonstrated that Pd nanoparticles less than 2 nm in particle size with amorphous-like structures and Pd particles with large, well-ordered structures favor the formation of a high fraction of corner sites and Pd(111) facets, respectively., ファイル公開：2020/09/07

Published
2019

32. Tuning the oxygen release properties of CeO2-based catalysts by metal–support interactions for improved gasoline soot combustion

Author

Ashikaga, Ryota, Murata, Kazumasa, Ito, Tetsuya, Yamamoto, Yuta, Arai, Shigeo, Satsuma, Atsushi, Ashikaga, Ryota, Murata, Kazumasa, Ito, Tetsuya, Yamamoto, Yuta, Arai, Shigeo, and Satsuma, Atsushi

Abstract

To develop highly active soot combustion catalysts for gasoline direct injection exhausts under low oxygen concentration conditions, CeO2 supported-metal catalysts (M/CeO2, M = Mn, Fe, Co, Ni, Cu, Rh, Pd, and Ag) were examined. Among the catalysts tested, Cu/CeO2 and Rh/CeO2 displayed the highest soot combustion activity. By comparing the activities of Cu-based catalysts with and without a Cu–CeO2 interface, the importance of such an interface for soot combustion was inferred. The oxygen release rate of CeO2-based catalysts, enhanced by metal–CeO2 interactions, was indicated as the controlling factor of catalytic activity. The soot oxidation activity and oxygen release rate were also demonstrated to correlate with metal–oxygen bond energy. Based on the redox properties and structural characteristics of CeO2-based catalysts, loading CeO2 with Cu or Rh, which have moderate M–O bond energy, was concluded to be optimal both in terms of the dispersion of supported-metal species and reducibility of the CeO2-based catalyst.

Published
2021

33. Time Resolved in situ DXAFS Revealing Highly Active Species of PdO Nanoparticle Catalyst for CH4 Oxidation

Author

Mahara, Yuji, Murata, Kazumasa, Ueda, Kakuya, Ohyama, Junya, Kato, Kazuo, and Satsuma, Atsushi

Subjects
Supported Pd catalysts, In situ XAFS spectroscopy, Methane combustion, Dispersive XAFS, Pd redox
Abstract

The highly active species of Pd/Al2O3 catalysts for methane combustion was revealed by in situ time‐resolved dispersive X‐ray absorption fine structure (DXAFS) spectroscopy. By using CH4 as a reduction agent, PdO in Pd/Al2O3 is reduced in a 2‐step model involving Pd0 nucleation and growth of Pd0 domain in a PdO particle. Kinetic analysis of the 2‐step model reduction of PdO nanoparticles leads to a suggestion that partial formation of Pd^0 in a PdO particle accelerates methane combustion., ファイル公開：2019-08-21

Published
2018

35. Effect of Bioactive Glass-Based Root Canal Sealer on the Incidence of Postoperative Pain after Root Canal Obturation

Author

Washio, Ayako, primary, Miura, Hiroki, additional, Morotomi, Takahiko, additional, Ichimaru-Suematsu, Miki, additional, Miyahara, Hirotake, additional, Hanada-Miyahara, Kaori, additional, Yoshii, Shinji, additional, Murata, Kazumasa, additional, Takakura, Nana, additional, Akao, Eiichi, additional, Fujimoto, Masataka, additional, Matsuyama, Atsushi, additional, and Kitamura, Chiaki, additional

Published
2020
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48. Kinetic analysis of Ag particle redispersion into ZSM-5 in the presence of coke using in situXAFSElectronic supplementary information (ESI) available. See DOI: 10.1039/d0cy01989e

Author

Murata, Kazumasa, Ohyama, Junya, and Satsuma, Atsushi

Abstract

In the present study, the redispersion behavior of Ag particles on ZSM-5 in the presence of coke was observed using in situX-ray absorption fine structure (XAFS) spectroscopy. The dynamics of Ag particle redispersion into the ZSM-5 pores were evaluated by linear combination fitting (LCF) of the X-ray absorption near edge structure (XANES) spectra. In addition, the behavior of coke combustion in Ag-ZSM-5 was observed by thermogravimetric analysis (TGA). The rate constant of Ag particle redispersion was smaller than that of coke combustion at ≥500 °C, but it was three times larger than that of coke combustion at <500 °C. According to 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR), the Ag+ions in the ZSM-5 pores improved the hydrothermal stability of Ag-ZSM-5. Therefore, a two-step regeneration process, in which the Ag particle redispersion proceeded first at low temperature (<500 °C) followed by a complete combustion of the coke at high temperature (≥500 °C) to prolong the catalyst lifetime, was used.

Published
2021
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49. Relationship between penta-coordinated Al3+sites in the Al2O3supports and CH4combustion activity of Pd/Al2O3catalystsElectronic supplementary information (ESI) available. See DOI: 10.1039/d1cy00098e

Author

Murata, Kazumasa, Shiotani, Takumi, Ohyama, Junya, Wakabayashi, Ryutaro, Maruoka, Hirokazu, Kimura, Tatsuo, and Satsuma, Atsushi

Abstract

Pd/Al2O3catalysts were prepared using various Al2O3supports with different structural features such as crystalline phase and crystallinity related to Al3+coordination, revealing a significant insight into the methane (CH4) combustion activity of Pd nanoparticles with the fraction of penta-coordinated Al3+sites in the Al2O3supports.

Published
2021
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50. Identification of active sites in CO oxidation over a Pd/Al2O3 catalyst.

Author

Murata, Kazumasa, Eleeda, Eleen, Ohyama, Junya, Yamamoto, Yuta, Arai, Shigeo, and Satsuma, Atsushi

Abstract

The active sites of Pd/Al2O3 catalysts for CO oxidations were identified by investigating the dependence of CO oxidation activities on the surface structure and morphology of Pd nanoparticles. The maximum catalytic activity was obtained for Pd particles approximately 2 nm in particle size. We performed structural analyses on the Pd surface through infrared (IR) spectroscopy of the adsorbed CO molecules. A positive correlation was obtained between catalytic activity and the fraction of linear CO adsorbed on Pd corner sites and Pd(111) facets, indicating that these sites are highly active for CO oxidation. X-ray absorption fine structure (XAFS) and spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) measurements demonstrated that Pd nanoparticles less than 2 nm in particle size with amorphous-like structures and Pd particles with large, well-ordered structures favor the formation of a high fraction of corner sites and Pd(111) facets, respectively. [ABSTRACT FROM AUTHOR]

Published
2019
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