研究者詳細 - 永岡　勝俊

論文 - 永岡　勝俊

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Realization of Ideal Ba Promoter State by Simultaneous Incorporation with Co into Carbon-protective Framework for Ammonia Synthesis Catalyst 査読有り

De Silva K.K.H., Sato K., Naito T., Toriyama T., Yamamoto T., Aso R., Murakami Y., Varadwaj P.R., Asahi R., Inazu K., Nagaoka K.

Advanced Energy Materials 15 巻 ( 8 ) 2024年12月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Advanced Energy Materials

Developing non-noble metal catalysts with excellent NH3 synthesis activity under mild conditions is a long-term goal. The best catalysts reported to date often require laborious fabrication methods and controlled environments to fabricate the catalysts or high temperatures and long times to activate the catalysts. This work introduces a facile one-pot method to fabricate carbon (C)-based, barium (Ba)-promoted cobalt (Co) catalysts via the citric acid sol–gel method with metal nitrates as precursors and water as the solvent. This approach ensures the homogeneous incorporation of metal ions into the carbon framework. The resulting (Ba/Co)0.3/C catalyst demonstrates an outstanding NH3 synthesis activity of 34 mmol gcat−1 h−1 (350 °C, 1.0 MPa) with excellent stability. In-depth characterizations reveal that Ba exists as barium oxide (BaO), uniformly distributed on the carbon framework and around the Co nanoparticles. It is uncovered that retarding barium carbonate (BaCO3) formation in the fresh catalyst significantly reduces the reduction temperature and time (485 °C/4 h), which is a fundamental advantage of this method. Density functional theory and molecular dynamics simulations indeed support the experimental observations. It is anticipated that this simple and economical strategy will resolve the issues in a broad field of heterogeneous catalyst research.

DOI： 10.1002/aenm.202404030

Efficient metallic Ni as a bifunctional electrocatalyst for integrating continuous PET plastic upcycling with hydrogen production 査読有り国際共著

Li X., Sun J., Ma H., Long X., Li T., Shimoyama Y., Naito T., Sato K., Yamada H., Nagaoka K., Zhao Y., Qian X.

Applied Catalysis B: Environmental 371 巻 2025年8月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Applied Catalysis B: Environmental

Electrocatalytic upcycling of polyethylene terephthalate (PET) plastic wastes into value-added chemicals is promising to alleviate the environmental and energy crisis. However, the cost effectiveness and long-term stability are still facing great challenges for up-scaling applications. Herein, we developed an efficient and stable metallic Ni bifunctional electrocatalyst for the electrocatalytic upcycling of PET plastic wastes coupled with hydrogen production. The metallic Ni deposited on nickel foam exhibited a current density of 100 mA cm−2 at 1.4 VRHE, and an optimal Faradaic efficiency to formic acid (FEFA) of 90 % at 1.5 VRHE for the anodic ethylene glycol oxidation reaction (EGOR), while presenting an overpotential of 250 mV at 100 mA cm−2 and Faradaic efficiency to hydrogen (FEH2) close to 100 % for the cathodic hydrogen evolution reaction (HER). Mechanistic studies demonstrated the structural reconstruction of metallic Ni into amorphous nickel (oxy)hydroxides as the reactive sites for the EGOR process. A flow cell reactor was assembled by utilizing the bifunctional electrocatalyst as both anode and cathode. A long-term stability was achieved at a constant current density of 100 mA cm−2 for 720 h. The superior catalytic performance, long-term stability and economic efficiency of the bifunctional metallic Ni electrocatalyst provide great potential for future scaling up.

DOI： 10.1016/j.apcatb.2025.125211

Atomic behaviors in PdRu solid-solution nanoparticles on CeO2-ZrO2 support for the three-way catalytic reaction 査読有り Open Access

Seo O., Tayal A., Kim J., Kusada K., Yamamoto T., Tang J., Hiroi S., Song C., Sato K., Nagaoka K., Haneda M., Kato K., Matsumura S., Kitagawa H., Sakata O.

Materials Today Catalysis 7 巻頁： 100078 - 100078 2024年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Materials Today Catalysis

Understanding the behavior of noble-metal catalysts is a key point of catalysis research aimed at reducing the environmental and economic costs associated with the increased use of automobiles. In this study, the atomic-behaviors of Ru and Pd atoms in PdRu solid-solution nanoparticles (NPs) supported on CeO2-ZrO2 (CZ) as a Rh-free three-way catalyst in a modeled three-way catalytic reaction (TWCR) were elucidated using a gas conversion analysis, transmission electron microscopy, and in-situ X-ray absorption fine structure spectroscopy. We found that the PdRu NPs enlarged by the annealing effect separated a smaller grain size with the Pd-rich and Ru-rich phase under TWCR. Most of the oxidation and reduction reactions under the modeled TWCR occurred on the Ru. However, the Pd metals acted as a major role of the reduction of NO gas and oxidation of CO and C3H6 gas. Ru atoms just is a minor role during the modeled TWCR. This study demonstrates the potential of PdRu NPs as a three-way catalyst and reveals the atomic-behavior and catalytic role under the modeled TWCR.

DOI： 10.1016/j.mtcata.2024.100078

Significant low-temperature activity of tetragonal type ZrO2-supported Ru catalysts for CO2 methanation 査読有り

Sato, K; Higuchi, H; Nagaoka, K

CHEMISTRY LETTERS 53 巻 ( 10 ) 2024年10月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemistry Letters

Conversion of CO2 with H2 to CH4 is a potential route for the utilization of CO2. Because CO2 methanation is an exothermic reaction, the equilibrium yield decreases with increasing temperature. A catalyst that exhibits high activity at low temperatures is thus highly desirable. We report here that a tetragonal-type ZrO2-supported Ru catalyst prepared by low-temperature calcination showed significant low-temperature activity for CO2 methanation. We surmise that an intermediate formate species formed over the tetragonal-type ZrO2 and enhanced the catalytic activity.

DOI： 10.1093/chemle/upae178

Rapid start-up of carbon-free H<sub>2</sub> production by ammonia oxidative decomposition over Co/Ce<sub>0.5</sub> Zr<sub>0.5</sub> O<sub>2</sub> with microwave irradiation 査読有り Open Access

Matsunaga, T; Hayashi, S; Yamada, H; Sato, K; Nagaoka, K

ISCIENCE 27 巻 ( 8 ) 頁： 110452 - 110452 2024年8月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：iScience

Hydrogen is a promising combustion improver for use with ammonia fuels, but a cost-effective method for easily producing hydrogen from ammonia at a high rate has yet to be developed. Here, we show that microwave irradiation instantly triggers oxidative decomposition of ammonia over a Co/Ce0.5Zr0.5O2 catalyst to produce hydrogen at a high rate. The microwave irradiation rapidly heats the inside of the catalyst from room temperature to the catalytic auto-ignition temperature of ammonia, thus initiating exothermic oxidative decomposition of ammonia to produce hydrogen. This method provides a highly efficient means of producing hydrogen for potential use in a carbon-free, ammonia-fueled power generation process.

DOI： 10.1016/j.isci.2024.110452

Barium-doped iron nanoparticles supported on MgO as an efficient catalyst for ammonia synthesis under mild reaction conditions 査読有り Open Access

Era K., Sato K., Miyahara S.I., Naito T., De Silva K., Akrami S., Yamada H., Toriyama T., Tamaoka T., Yamamoto T., Murakami Y., Inazu K., Nagaoka K.

Sustainable Energy and Fuels 8 巻 ( 12 ) 頁： 2593 - 2600 2024年5月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Sustainable Energy and Fuels

To realize a carbon-neutral society, developing highly active and inexpensive catalysts for ammonia (NH3) production working under moderate conditions (<400 °C, <10 MPa) using hydrogen fabricated from the electrolysis of water is demanded. Current industrial fused iron (Fe) catalysts show deficient activity under such conditions. Although Ru-based catalysts have been introduced as highly efficient catalysts working under desired conditions, they are scarce and consequently expensive. This work introduces Fe/Ba/MgO (reduced at 700 °C) as an active catalyst with a high ammonia production rate working at mild temperature and pressure (350 °C, 1.0 MPa). Ba doping to Fe nanoparticles supported on MgO and pre-reduction at high temperatures dramatically ameliorated the NH3 production rate. Due to the absence of hydrogen poisoning, the catalytic activity of the Fe/Ba/MgO increased gradually by raising the pressure from 0.1 to 3.0 MPa. The activity of this catalyst at 3.0 MPa was higher than that of two benchmark Ru catalysts. After pre-reduction at high temperature, electrons are donated from the BaO encapsulating the Fe0 nanoparticles to the N2 molecule, which promotes the rate-determining step of ammonia synthesis. We anticipate that these findings will contribute to developing inexpensive Fe catalysts for decarbonizing the ammonia synthesis process to achieve a carbon-neutral society.

DOI： 10.1039/d4se00411f

Effects of the Topological Structure of Different Cu-Zeolites on the Relationship between Soot and NOx Removal on NH3–SCRF 査読有り

Zhimu Ye, Pengcheng Zhao, Xincheng Tang, Takeshi Hagio, Katsutoshi Sato, Katsutoshi Nagaoka, Xinling Li

Energy & Fuels 38 巻頁： 2212 - 2223 2024年1月

Catalytic Behavior of K-doped Fe/MgO Catalysts for Ammonia Synthesis Under Mild Reaction Conditions 査読有り Open Access

Era K., Sato K., Miyahara S.i., Naito T., De Silva K., Akrami S., Yamada H., Toriyama T., Yamamoto T., Murakami Y., Aika K.i., Inazu K., Nagaoka K.

ChemSusChem 16 巻 ( 22 ) 頁： e202300942 2023年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ChemSusChem

An important part of realizing a carbon-neutral society using ammonia will be the development of an inexpensive yet efficient catalyst for ammonia synthesis under mild reaction conditions (<400 °C, <10 MPa). Here, we report Fe/K(3)/MgO, fabricated via an impregnation method, as a highly active catalyst for ammonia synthesis under mild reaction conditions (350 °C, 1.0 MPa). At the mentioned conditions, the activity of Fe/K(3)/MgO (17.5 mmol h−1 gcat−1) was greater than that of a commercial fused iron catalyst (8.6 mmol h−1 gcat−1) currently used in the Haber-Bosch process. K doping was found to increase the ratio of Fe0 on the surface and turnover frequency of Fe in our Fe/K(3)/MgO catalyst. In addition, increasing the pressure to 3.0 MPa at the same temperature led to a significant improvement of the ammonia synthesis rate to 29.6 mmol h−1 gcat−1, which was higher than that of two more expensive, benchmark Ru-based catalysts, which are also potential alternative catalysts. A kinetics analysis revealed that the addition of K enhanced the ammonia synthesis activity at ≥300 °C by changing the main adsorbed species from NH to N which can accelerate dissociative adsorption of nitrogen as the rate limiting step in ammonia synthesis.

DOI： 10.1002/cssc.202300942

DOI： 10.1002/cssc.202300942

The Effect of Ru Precursor and Support on the Hydrogenation of Aromatic Aldehydes/Ketones to Alcohols 査読有り Open Access

Chaudhari, C; Sato, K; Miyahara, S; Yamamoto, T; Toriyama, T; Matsumura, S; Kusuda, K; Kitagawa, H; Nagaoka, K

CHEMCATCHEM 14 巻 ( 16 ) 2022年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ChemCatChem

Supported Ru catalysts were prepared by using different Ru precursors and examined for the hydrogenation of benzaldehyde to CHM. The catalyst prepared from Ru3(CO)12 precursor and HT support exhibited high yield of CHM. Moderate acidic and basic nature of HT was favourable to control the selectivity for CHM. The physicochemical properties analysis revealed that highly dispersed Ru nanoparticles were effective for the hydrogenation of benzaldehyde. RuCO/HT catalyst was tolerant to different functional groups and was stable until 7th cycle of recycle study.

DOI： 10.1002/cctc.202200241

Co Nanoparticle Catalysts Encapsulated by BaO-La<sub>2</sub>O<sub>3</sub> Nanofractions for Efficient Ammonia Synthesis Under Mild Reaction Conditions 査読有り Open Access

Miyahara, SI; Sato, K; Tsujimaru, K; Wada, Y; Ogura, Y; Toriyama, T; Yamamoto, T; Matsumura, S; Inazu, K; Nagaoka, K

ACS OMEGA 7 巻 ( 28 ) 頁： 24452 - 24460 2022年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Omega

Ruthenium catalysts may allow for realization of renewable energy-based ammonia synthesis processes using mild reaction conditions (<400 °C, <10 MPa). However, ruthenium is relatively rare and therefore expensive. Here, we report a Co nanoparticle catalyst loaded on a basic Ba/La2O3support and prereduced at 700 °C (Co/Ba/La2O3_700red) that showed higher ammonia synthesis activity at 350 °C and 1.0-3.0 MPa than two benchmark Ru catalysts, Cs+/Ru/MgO and Ru/CeO2. The synthesis rate of the catalyst at 350 °C and 1.0 MPa (19.3 mmol h-1g-1) was 8.0 times that of Co/Ba/La2O3_500red and 6.9 times that of Co/La2O3_700red. The catalyst showed ammonia synthesis activity at temperatures down to 200 °C. Reduction at the high temperature induced the formation of BaO-La2O3nanofractions around the Co nanoparticles by decomposition of BaCO3, which increased turnover frequency, inhibited the sintering of Co nanoparticles, and suppressed ammonia poisoning. These strategies may also be applicable to other non-noble metal catalysts, such as nickel.

DOI： 10.1021/acsomega.2c01973

Operando Spectroscopic Study of the Dynamics of Ru Catalyst during Preferential Oxidation of CO and the Prevention of Ammonia Poisoning by Pt 査読有り Open Access

Sato, K; Zaitsu, S; Kitayama, G; Yagi, S; Kayada, Y; Nishida, Y; Wada, Y; Nagaoka, K

JACS AU 2 巻 ( 7 ) 頁： 1627 - 1637 2022年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JACS Au

Hydrogen is a promising clean energy source. In domestic polymer electrolyte fuel cell systems, hydrogen is produced by reforming of natural gas; however, the reformate contains carbon monoxide (CO) as a major impurity. This CO is removed from the reformate by a combination of the water-gas shift reaction and preferential oxidation of CO (PROX). Currently, Ru-based catalysts are the most common type of PROX catalyst; however, their durability against ammonia (NH3) as an impurity produced in situ from trace amounts of nitrogen also contained in the reformate is an important issue. Previously, we found that addition of Pt to an Ru catalyst inhibited deactivation by NH3. Here, we conducted operando XAFS and FT-IR spectroscopic analyses with simultaneous gas analysis to investigate the cause of the deactivation of an Ru-based PROX catalyst (Ru/α-Al2O3) by NH3and the mechanism of suppression of the deactivation by adding Pt (Pt/Ru/α-Al2O3). We found that nitric oxide (NO) produced by oxidation of NH3induces oxidation of the Ru nanoparticle surface, which deactivates the catalyst via a three-step process: First, NO directly adsorbs on Ru0to form NO-Ruδ+, which then induces the formation of O-Run+by oxidation of the surrounding Ru0. Then, O-Rum+is formed by oxidation of Ru0starting from the O-Run+nuclei and spreading across the surface of the nanoparticle. Pt inhibits this process by alloying with Ru and inducing the decomposition of adsorbed NO, which keeps the Ru in a metallic state.

DOI： 10.1021/jacsau.2c00195

Direct high-purity hydrogen production from ammonia by using a membrane reactor combining V-10mol%Fe hydrogen permeable alloy membrane with Ru/Cs<inf>2</inf>O/Pr<inf>6</inf>O<inf>11</inf> ammonia decomposition catalyst 査読有り Open Access

Omata K., Sato K., Nagaoka K., Yukawa H., Matsumoto Y., Nambu T.

International Journal of Hydrogen Energy 47 巻 ( 13 ) 頁： 8372 - 8381 2022年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Hydrogen Energy

The hydrogen production capabilities of the membrane reactor combining V-10 mol%Fe hydrogen permeable alloy membrane with Ru/Cs2O/Pr6O11 ammonia decomposition catalyst are studied. The ammonia conversion is improved by 1.7 times compared to the Ru/Cs2O/Pr6O11 catalyst alone by removing the produced hydrogen through the V-10mol%Fe alloy membrane during the ammonia decomposition. 79% of the hydrogen atoms contained in the ammonia gas are extracted directly as high-purity hydrogen gas. Both the Ru/Cs2O/Pr6O11 catalyst and the V-10 mol% Fe alloy membrane are highly durable, and the initial performance of the hydrogen separation rate lasts for more than 3000 h. The produced hydrogen gas conforms to ISO 14687–2:2019 Grade D for fuel cell vehicles because the ammonia and nitrogen concentrations are less than 0.1 ppm and 100 ppm, respectively.

DOI： 10.1016/j.ijhydene.2021.12.191

Rh-PVP Catalyzed Reductive Amination of Phenols by Ammonia or Amines to Cyclohexylamines under Solvent-free Conditions 査読有り Open Access

Chaudhari C., Sato K., Rumi S., Nishida Y., Shiraishi M., Nagaoka K.

Chemistry Letters 51 巻 ( 1 ) 頁： 81 - 84 2022年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemistry Letters

Colloidal metal nanoparticles were examined for reductive amination of phenol by ammonia under mild reaction conditions. The results showed that Rh-PVP was the most active catalyst for reductive amination reaction. Linear, cyclic, and amino alcohols were used as nucleophiles and converted to primary/secondary/tertiary amines. Using this strategy, the synthesis of an industrially important chemical, N-cyclohexyl- 2-pyrrolidone was explored.

DOI： 10.1246/cl.210574

Nitrile hydrogenation to secondary amines under ambient conditions over palladium-platinum random alloy nanoparticles 査読有り Open Access

Nishida Y., Sato K., Chaudhari C., Yamada H., Toriyama T., Yamamoto T., Matsumura S., Aspera S.M., Nakanishi H., Haneda M., Nagaoka K.

Catalysis Science and Technology 12 巻 ( 13 ) 頁： 4128 - 4137 2022年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Catalysis Science and Technology

Catalytic hydrogenation of nitriles is a cost-effective and green method for synthesizing amines and imines, which have many industrial applications. However, this reaction generally requires harsh reaction conditions and produces a mixture of amine and imine products due to its chemodiversity. Therefore, it is a challenge to selectively hydrogenate nitriles to a single product under ambient conditions (1 bar of H2 at 25 °C). Here, we report an effective method for selective hydrogenation of nitriles that does not require heat, pressurization, or long reaction times. We achieved this by means of bimetalization between palladium (Pd) and platinum (Pt) nanoparticles, which resulted in a catalyst that showed high yield of secondary amines. Although Pd and Pt are thermodynamically immiscible, we have successfully alloyed the two metals by means of rapid chemical reduction assisted by microwave heating. X-ray absorption spectroscopy suggested the formation of heteroatomic Pdδ+Ptδ− sites via charge transfer between neighboring Pd and Pt atoms in the alloy structure. Moreover, Fourier transform IR spectroscopy and scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy indicated that decreasing the size of the PdPt (50 : 50) nanoparticles improved the degree of alloying and facilitated the formation of electron-enriched Ptδ− species. On the basis of kinetics studies and density functional theory calculations, we concluded that cyano group activation, which was the rate-determining step over monometallic Pd and Pt catalysts, was accelerated over the heteroatomic Pdδ+Ptδ− sites because of strong back-donation from electron-enriched Ptδ− species to the carbon atom of the cyano groups. The PdPt random alloy nanoparticles catalyzed the reactions of various aromatic and heterocyclic nitriles, and the corresponding secondary amines were selectively obtained in just a few hours.

DOI： 10.1039/d1cy02302k

Co/Ba/La2O3 catalyst for ammonia synthesis under mild reaction conditions 査読有り

Katsutoshi Nagaoka, Shin-ichiro Miyahara, Katsutoshi Sato, Yuta Ogura, Kotoko Tsujimaru, Yuichiro Wada, Takaaki Toriyama, Tomokazu Yamamoto, Syo Matsumura, Koji Inazu

2021年12月

Barium oxide encapsulating cobalt nanoparticles supported on magnesium oxide: Active non-noble metal catalysts for ammonia synthesis under mild reaction conditions 査読有り Open Access

Sato K., Nagaoka K., Miyahara S.I., Tsujimaru K., Wada Y., Toriyama T., Yamamoto T., Matsumura S., Inazu K., Mohri H., Iwasa T., Taketsugu T.

ACS Catalysis 11 巻 ( 21 ) 頁： 13050 - 13061 2021年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ACS Catalysis

To realize a carbon-free society, catalysts are needed for the synthesis of ammonia under mild reaction conditions (<400 °C, <10 MPa) that use hydrogen produced from renewable energy. Ru-based catalysts are currently the most promising candidates; however, Ru is expensive and of low abundance. Here, we discovered that the encapsulation of Co nanoparticles with BaO enhanced the ammonia synthesis activity of Co and that a simple Ba-doped Co/MgO catalyst prereduced at an unusually high temperature of 700 °C (Co@BaO/MgO-700red) showed outstanding ammonia synthesis activity. The ammonia synthesis rate (24.6 mmol gcat−1 h−1) and turnover frequency (0.246 s−1) of the catalyst at 350 °C and 1.0 MPa were about 80 and 250 times higher, respectively, than those of the nondoped parent catalyst. At the same temperature but higher pressure (3.0 MPa), the ammonia synthesis rate was increased to 48.4 mmol gcat−1 h−1, which is higher than that of active Ru-based catalysts. In addition, at 1.0 MPa, our catalyst produced ammonia even at temperatures as low as 150 °C. Scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy investigations revealed that after reduction at 700 °C, the Co nanoparticles had become encapsulated by a nanofraction of BaO. The mechanism underlying the formation of this unique structure was considered to comprise reduction of oxidic Co to metallic Co, decomposition of BaCO3 to BaO, and migration of BaO and Co nanoparticles. Spectroscopic and density functional theory investigations revealed that adsorption of N2 on the Co atoms at the catalyst surface weakened the N2 triple bond to the strength of a double bond due to electron donation from Ba2+ of BaO via adjacent Co atoms; this weakening accelerated the cleavage of the triple bond, which is the rate-determining step for ammonia synthesis.

DOI： 10.1021/acscatal.1c02887

Ammonia synthesis over lanthanoid oxide–supported ruthenium catalysts 査読有り Open Access

Miyahara S.i., Sato K., Kawano Y., Imamura K., Ogura Y., Tsujimaru K., Nagaoka K.

Catalysis Today 376 巻頁： 36 - 40 2021年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Catalysis Today

Ammonia synthesis catalysts with high activity under mild reaction conditions for use in synthetic chemical processes powered by renewable energy are needed. Here, we investigated the physicochemical properties and ammonia synthesis activity of lanthanoid oxide–supported Ru catalysts. The basicity of the Ru/lanthanoid oxide catalysts, as estimated by CO2 temperature-programmed desorption, was higher than that of Ru/MgO, a representative catalyst with high ammonia synthesis activity, and a positive relationship was observed between basicity and turnover frequency. The turnover frequency of Ru/Pr2O3 and Ru/La2O3 (both 0.24 s−1) was eight times that of Ru/MgO (0.03 s−1). A kinetic analysis revealed that hydrogen poisoning, which is a typical drawback of oxide-supported Ru catalysts, was markedly retarded in the Ru/lanthanoid oxide catalysts. As a result, the ammonia synthesis rate of the Ru/Pr2O3 catalyst increased with increasing reaction pressure, reaching 49 mmol g−1 h−1 at 400 °C and 1.0 MPa, which was 12 times that of Ru/MgO under the same conditions.

DOI： 10.1016/j.cattod.2020.08.031

One-pot synthesis of cyclohexylamine and <i>N</i>-aryl pyrroles <i>via</i> hydrogenation of nitroarenes over the Pd<sub>0.5</sub>Ru<sub>0.5</sub>-PVP catalyst 査読有り

Chaudhari, C; Sato, K; Ikeda, Y; Terada, K; Abe, N; Nagaoka, K

NEW JOURNAL OF CHEMISTRY 45 巻 ( 22 ) 頁： 9743 - 9746 2021年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：New Journal of Chemistry

The direct synthesis of cyclohexylamine via the hydrogenation of nitrobenzene over monometallic (Pd, Ru or Rh) and bimetallic (PdxRu1-x) catalysts was studied. The Pd0.5Ru0.5-PVP catalyst was the most effective catalyst for this reaction. The catalyst can be reused and applied for the synthesis of N-aryl pyrroles and quinoxalines from nitrobenzenes.

DOI： 10.1039/d1nj00922b

Highly Stable and Active Solid-Solution-Alloy Three-Way Catalyst by Utilizing Configurational-Entropy Effect 査読有り

Kusada K., Wu D., Nanba Y., Koyama M., Yamamoto T., Tran X.Q., Toriyama T., Matsumura S., Ito A., Sato K., Nagaoka K., Seo O., Song C., Chen Y., Palina N., Kumara L.S.R., Hiroi S., Sakata O., Kawaguchi S., Kubota Y., Kitagawa H.

Advanced Materials 33 巻 ( 16 ) 頁： e2005206 2021年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Advanced Materials

Since 1970, people have been making every endeavor to reduce toxic emissions from automobiles. After the development of a three-way catalyst (TWC) that concurrently converts three harmful gases, carbon monoxide (CO), hydrocarbons (HCs), and nitrogen oxides (NOx), Rh became an essential element in automobile technology because only Rh works efficiently for catalytic NOx reduction. However, due to the sharp price spike in 2007, numerous efforts have been made to replace Rh in TWCs. Nevertheless, Rh remains irreplaceable, and now, the price of Rh is increasing significantly again. Here, it is demonstrated that PdRuM ternary solid-solution alloy nanoparticles (NPs) exhibit highly durable and active TWC performance, which will result in a significant reduction in catalyst cost compared to Rh. This work provides insights into the design of highly durable and efficient functional alloy NPs, guiding how to best take advantage of the configurational entropy in addition to the mixing enthalpy.

DOI： 10.1002/adma.202005206

Boosting Ammonia Synthesis under Mild Reaction Conditions by Precise Control of the Basic Oxide–Ru Interface

Sato Katsutoshi, Nagaoka Katsutoshi

Chemistry Letters 50 巻 ( 4 ) 頁： 687 - 696 2021年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：公益社団法人日本化学会

<p>Strong basic oxide–supported Ru catalysts are easily prepared and handled, and they have been used as effective catalysts for ammonia synthesis under mild reaction conditions since the 1970s. Recent research has revealed that precise control of the boundary states between the basic oxide (i.e., rare-earth oxide, alkali earth oxide), oxygen defect sites, and Ru nanoparticles can be used to enhance ammonia synthesis under mild reaction conditions and inhibit hydrogen poisoning, which is a typical drawback of strong basic oxide–supported Ru catalysts.</p>

DOI： 10.1246/CL.200855

DOI： 10.1246/cl.200855

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