Faculty Profiles - NAGAOKA Katsutoshi

Papers - NAGAOKA Katsutoshi

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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 Reviewed Open Access

Kaori Omata, Katsutoshi Sato, Katsutoshi Nagaoka, Hiroshi Yukawa, Yoshihisa Matsumoto, Tomonori Nambu

International Journal of Hydrogen Energy Vol. 47 ( 13 ) page： 8372 - 8381 2022.2

Language：English Publishing type：Research paper (scientific journal)

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 Reviewed Open Access

Chandan Chaudhari, Katsutoshi Sato, Saeki Rumi, Yoshihide Nishida, Masaya Shiraishi, Katsutoshi Nagaoka

Chemistry Letters Vol. 51 ( 1 ) page： 81 - 84 2022.1

Language：English Publishing type：Research paper (scientific journal) Publisher：The Chemical Society of Japan

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 Reviewed Open Access

Yoshihide Nishida, Katsutoshi Sato, Chandan Chaudhari, Hiroshi Yamada, Takaaki Toriyama, Tomokazu Yamamoto, Syo Matsumura, Susan Meñez Aspera, Hiroshi Nakanishi, Masaaki Haneda, Katsutoshi Nagaoka

Catalysis Science and Technology Vol. 12 ( 13 ) page： 4128 - 4137 2022

Language：English Publishing type：Research paper (scientific journal)

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 Reviewed

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

2021.12

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

Katsutoshi Sato, Katsutoshi Nagaoka, Shin Ichiro Miyahara, Kotoko Tsujimaru, Yuichiro Wada, Takaaki Toriyama, Tomokazu Yamamoto, Syo Matsumura, Koji Inazu, Hirono Mohri, Takeshi Iwasa, Tetsuya Taketsugu

ACS Catalysis Vol. 11 ( 21 ) page： 13050 - 13061 2021.11

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

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 Reviewed Open Access

Shin ichiro Miyahara, Katsutoshi Sato, Yukiko Kawano, Kazuya Imamura, Yuta Ogura, Kotoko Tsujimaru, Katsutoshi Nagaoka

Catalysis Today Vol. 376 page： 36 - 40 2021.9

Language：English Publishing type：Research paper (scientific journal)

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: N -aryl pyrroles via hydrogenation of nitroarenes over the Pd<inf>0.5</inf>Ru<inf>0.5</inf>-PVP catalyst Reviewed

Chandan Chaudhari, Katsutoshi Sato, Yasuyuki Ikeda, Kenji Terada, Naoya Abe, Katsutoshi Nagaoka

New Journal of Chemistry Vol. 45 ( 22 ) page： 9743 - 9746 2021.6

Language：English Publishing type：Research paper (scientific journal)

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 Reviewed

Kohei Kusada, Dongshuang Wu, Yusuke Nanba, Michihisa Koyama, Tomokazu Yamamoto, Xuan Quy Tran, Takaaki Toriyama, Syo Matsumura, Ayano Ito, Katsutoshi Sato, Katsutoshi Nagaoka, Okkyun Seo, Chulho Song, Yanna Chen, Natalia Palina, Loku Singgappulige Rosantha Kumara, Satoshi Hiroi, Osami Sakata, Shogo Kawaguchi, Yoshiki Kubota, Hiroshi Kitagawa

Advanced Materials Vol. 33 ( 16 ) page： e2005206 2021.4

Language：English Publishing type：Research paper (scientific journal)

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 oxideru interface Open Access

Katsutoshi Sato, Katsutoshi Nagaoka

Chemistry Letters Vol. 50 ( 4 ) page： 687 - 696 2021.4

Language：English Publishing type：Research paper (scientific journal) Publisher：The Chemical Society of Japan

Strong basic oxidesupported 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 oxidesupported Ru catalysts.

DOI： 10.1246/CL.200855

DOI： 10.1246/cl.200855

Nonequilibrium Flow-Synthesis of Solid-Solution Alloy Nanoparticles: From Immiscible Binary to High-Entropy Alloys Reviewed

Kohei Kusada, Tomokazu Yamamoto, Takaaki Toriyama, Syo Matsumura, Katsutoshi Sato, Katsutoshi Nagaoka, Kenji Terada, Yasuyuki Ikeda, Yoshinari Hirai, Hiroshi Kitagawa

Journal of Physical Chemistry C Vol. 125 ( 1 ) page： 458 - 463 2021.1

Language：English Publishing type：Research paper (scientific journal)

Solid-solution alloy nanoparticles (NPs), where the constituents mix at the atomic level, show a variety of attractive properties due to their tunable electronic structures. However, it is still difficult to stably synthesize them, particularly nonequilibrium alloys that consist of combinations immiscible in the bulk. Here, we first report the successful syntheses of solid-solution alloy NPs including PdRu and PdRuIr, which are immiscible in the bulk, and of IrPdPtRhRu high-entropy alloy NPs through a continuous-flow reactor providing a high productivity with high reproducibility. The designed solvothermal flow reactor enabled us to use a lower alcohol as a reductant that cannot be applied in a batch synthesis for these NPs.

DOI： 10.1021/acs.jpcc.0c08871

Chemoselective hydrogenation of heteroarenes and arenes by Pd-Ru-PVP under mild conditions Reviewed Open Access

Chandan Chaudhari, Katsutoshi Sato, Yoshihide Nishida, Tomokazu Yamamoto, Takaaki Toriyama, Syo Matsumura, Yasuyuki Ikeda, Kenji Terada, Naoya Abe, Kohei Kusuda, Hiroshi Kitagawa, Katsutoshi Nagaoka

RSC Advances Vol. 10 ( 72 ) page： 44191 - 44195 2020.12

Language：English Publishing type：Research paper (scientific journal)

Monometallic (Pd, Ru or Rh) and bimetallic (Pd0.5-Ru0.5) alloy NPs catalysts were examined for the hydrogenation of quinoline. Pd-Ru alloy catalyst showed superior catalytic activity to the traditional Rh catalyst. The characterization of Pd0.5-Ru0.5 catalysts, HAADF-EDX mapping and XPS analysis suggested that the alloy state of PdRu catalysts remained unchanged in the recovered catalyst. Furthermore, the catalyst was highly selective for the hydrogenation of different arenes. This journal is

DOI： 10.1039/d0ra09981c

One-pot synthesis of pyrrolidones from levulinic acid and amines/nitroarenes/nitriles over the Ir-PVP catalyst Reviewed

Chandan Chaudhari, Masaya Shiraishi, Yoshihide Nishida, Katsutoshi Sato, Katsutoshi Nagaoka

Green Chemistry Vol. 22 ( 22 ) page： 7760 - 7764 2020.11

Language：English Publishing type：Research paper (scientific journal)

The synthesis of pyrrolidones via reductive amination of levulinic acid with aniline was examined over polypyrrolidone-stabilized metal nanoparticle catalysts. Among them, Ir metal was the most effective and applicable for the reductive amination of levulinic acid with nitroarenes/nitriles. Importantly, this catalyst was used for the one-pot synthesis of the anti-inflammatory drug indoprofen from 2-formylbenzoic acid and 2-(4-nitrophenyl)propanoic acid.

DOI： 10.1039/d0gc01725f

Coreduction methodology for immiscible alloys of CuRu solid-solution nanoparticles with high thermal stability and versatile exhaust purification ability Reviewed Open Access

Bo Huang, Hirokazu Kobayashi, Tomokazu Yamamoto, Syo Matsumura, Yoshihide Nishida, Katsutoshi Sato, Katsutoshi Nagaoka, Masaaki Haneda, Shogo Kawaguchi, Yoshiki Kubota, Hiroshi Kitagawa

Chemical Science Vol. 11 ( 42 ) page： 11413 - 11418 2020.11

Language：English Publishing type：Research paper (scientific journal)

This study provides a coreduction methodology for solid solution formation in immiscible systems, with an example of a whole-region immiscible Cu-Ru system. Although the binary Cu-Ru alloy system is very unstable in the bulk state, the atomic-level well-mixed CuRu solid solution nanoparticles were found to have high thermal stability up to at least 773 K in a vacuum. The exhaust purification activity of the CuRu solid solution was comparable to that of face-centred cubic Ru nanoparticles. According to in situ infrared measurements, stronger NO adsorption and higher intrinsic reactivity of the Ru site on the CuRu surface than that of a pure Ru surface were found, affected by atomic-level Cu substitution. Furthermore, CuRu solid solution was a versatile catalyst for purification of all exhaust gases at a stoichiometric oxygen concentration. This journal is

DOI： 10.1039/d0sc03373a

Oxidation of Ru/Ce<inf>0.5</inf>Zr<inf>0.5</inf>O<inf>2- x</inf>at Ambient Temperature as a Trigger for Carbon-Free H<inf>2</inf>Production by Ammonia Oxidative Decomposition Reviewed

Takahiro Matsunaga, Suguru Matsumoto, Ryo Tasaki, Yuta Ogura, Takaaki Eboshi, Yuma Takeishi, Kyoko Honda, Katsutoshi Sato, Katsutoshi Nagaoka

ACS Sustainable Chemistry and Engineering Vol. 8 ( 35 ) page： 13369 - 13376 2020.9

Language：English Publishing type：Research paper (scientific journal)

Ammonia has received attention as a hydrogen carrier for energy use, and although ammonia decomposition can produce hydrogen at a high rate, there is currently no simple process for decomposing ammonia that is easily and rapidly initiated at any time without an input of external energy. Here, we report the discovery of a process for initiating and sustaining the production of hydrogen from ammonia without heating the catalyst externally. The oxidative decomposition of ammonia to produce hydrogen at a high rate was repeatedly triggered at ambient temperature (∼25 °C) immediately after NH3 and O2 were supplied to a Ru/Ce0.5Zr0.5O2 catalyst that had been previously reduced at ambient temperature. For this catalyst, active hydrogen atoms formed on Ru0 nanoparticles reduced Ce0.5Zr0.5O2 even at ambient temperature, and the very exothermic oxidation of Ce0.5Zr0.5O2-x as well as Ru0 heated the catalyst bed to the catalytic auto-ignition temperature for ammonia combustion, which was lowered by the contribution of mobile (active) oxygen over the Ce0.5Zr0.5O2. Oxidative ammonia decomposition was thereby triggered.

DOI： 10.1021/acssuschemeng.0c04126

Effect of Calcination and Reduction Temperatures on the Catalytic Activity of Ru/La<inf>0.5</inf>Ce<inf>0.5</inf>O<inf>1.75</inf> for Ammonia Synthesis under Mild Conditions Reviewed Open Access

Yuta Ogura, Takahiro Asai, Katsutoshi Sato, Shin ichiro Miyahara, Takaaki Toriyama, Tomokazu Yamamoto, Syo Matsumura, Katsutoshi Nagaoka

Energy Technology Vol. 8 ( 6 ) page： 2000264 2020.6

Language：English Publishing type：Research paper (scientific journal)

© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Ammonia is a potential carrier of hydrogen as a zero-emission fuel. Herein, the effects of calcination and reduction temperatures on the ammonia-synthesis activity of Ru/La0.5Ce0.5O1.75 are investigated under mild synthesis conditions (≤400 °C, ≤3 MPa), which are the preferred conditions for the storage of hydrogen as an energy source. The highest catalytic activity is obtained after calcination of the support at 700 °C and reduction of the catalyst at 650 °C. Calcination using a higher temperature than that used for reduction results in the induction of a strong metal–support interaction (SMSI) effect. This high-temperature calcination also provides heat resistance to the support, which prevents sintering of the primary support particles during reduction. Thus, calcination and reduction at temperatures higher than those normally used for the preparation of Ru catalysts provide a novel approach for obtaining supported highly dispersed Ru catalysts exhibiting the SMSI effect and high catalytic activities.

DOI： 10.1002/ente.202000264

Pr<inf>2</inf>O<inf>3</inf> Supported Nano-layered Ruthenium Catalyzed Acceptorless Dehydrogenative Synthesis of 2-Substituted Quinolines and 1,8-Naphthyridines from 2-Aminoaryl Alcohols and Ketones Reviewed Open Access

Chandan Chaudhari, Katsutoshi Sato, Yuta Ogura, Shin Ichiro Miayahara, Katsutoshi Nagaoka

ChemCatChem Vol. 12 ( 8 ) page： 2198 - 2202 2020.4

Language：English Publishing type：Research paper (scientific journal)

Pr2O3 supported Ru nanolayers and Ru nanoparticles catalysts were examined for the synthesis of quinolines. The Ru nanolayer was most active catalyst and showed a broad substrate scope. Structure-activity relationship demonstrated that the metallic state and morphology of Ru as well as the basic site of Pr2O3 were indispensable factors of this catalytic system.

DOI： 10.1002/cctc.201902311

Surface dynamics for creating highly active ru sites for ammonia synthesis: Accumulation of a low-crystalline, oxygen-deficient nanofraction Reviewed

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

ACS Sustainable Chemistry and Engineering Vol. 8 ( 7 ) page： 2726 - 2734 2020.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

© 2020 American Chemical Society. To mitigate global problems related to energy and global warming, it is helpful to develop an ammonia synthesis process using catalysts that are highly active under mild conditions. Here we show that the ammonia synthesis activity per weight of catalyst of Ru/Ba/LaCeOx, prereduced at 700 °C, is the highest among reported oxide-supported Ru catalysts, 52.3 mmol h-1 gcat-1 at 350 °C, 1.0 MPa. The turnover frequency of Ru/Ba/LaCeOx at 350 °C was more than 8 times that of Cs+/Ru/MgO, which is a well-known active catalyst used as a benchmark; furthermore, hydrogen poisoning, a typical drawback for oxide-supported Ru catalysts, was effectively suppressed. Scanning transmission electron microscopy observations with energy dispersive X-ray spectrometry and electron energy loss spectroscopy analysis revealed that a low-crystalline, oxygen-deficient nanofraction including Ba2+, Ce3+, and La3+ had accumulated on the Ru particles. This unique structure was obtained by exploiting the surface dynamics of alkaline earth compounds and thermostable rare earth oxides that contain redox-active atoms during the reduction at an unusually high temperature. The nanofraction showed strong electron-donating ability because of the strong basicity of the included cations, removal of carbonate, and formation of oxygen defect sites that eliminated electron-withdrawing O2- anions from the interface between the nanofraction and Ru atom. Electrons were therefore effectively donated to antibonding π -orbitals of the N2 molecules via Ru in contact with the nanofraction, and NN triple bond cleavage, which is the rate-determining step for ammonia synthesis, was promoted.

DOI： 10.1021/acssuschemeng.9b06299

Kinetics of ammonia synthesis over Ru/Pr2O3 Reviewed

Kazuya Imamura, Shin-ichiro Miyahara, Yukiko Kawano, Katsutoshi Sato, Yuta Nakasaka, Katsutoshi Nagaoka

Journal of the Taiwan Institute of Chemical Engineers Vol. 105 page： 50 - 56 2019.12

Language：English Publishing type：Research paper (scientific journal)

We investigated the kinetics of NH3 synthesis over a catalyst consisting of low-crystalline Ru nano-layers supported on Pr2O3. We determined the reaction orders with respect to N2, H2, and NH3 at various temperatures and pressures over Ru/Pr2O3, as well as Ru/CeO2 and Ru/MgO. The reaction orders with respect to N2 were always almost unity for all the catalysts under all the reaction conditions, indicating that the rate-determining step was NN bond cleavage. In contrast, the reaction orders with respect to H2 differed among the catalysts and decreased with increasing pressure and increased with increasing temperature. Under all conditions, the reaction order with respect to H2 was largest over Ru/Pr2O3 and smallest over Ru/MgO, indicating that hydrogen poisoning of the Ru surface was retarded to a greater extent over Ru/Pr2O3 than over Ru/MgO. In agreement with the trends of the H2 reaction orders, the NH3 synthesis rates over Ru/Pr2O3 at 400 °C rose drastically (64 mmol h−1 g−1) as the pressure was increased from 0.1 to 3.0 MPa. Furthermore, decreasing the feed gas H2/N2 ratio at 3.0 MPa effectively increased the NH3 synthesis rate over Ru/Pr2O3, which reached 45 mmol h−1 g−1 at 350 °C at a H2/N2 ratio of 1/0.5.<br />

DOI： 10.1016/j.jtice.2019.10.006

Recyclable Rh-PVP nanoparticles catalyzed hydrogenation of benzoic acid derivatives and quinolines under solvent-free conditions Reviewed Open Access

Chandan Chaudhari, Hirotaka Imatome, Yoshihide Nishida, Katsutoshi Sato, Katsutoshi Nagaoka

Catalysis Communications Vol. 126 page： 55 - 60 2019.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier BV

Various transition metal nanoparticles, prepared by microwave-assisted alcohol reduction method were examined for hydrogenation of benzoic acid to cyclohexanecarboxylic acid under solvent-free conditions. Rh metal was the most effective catalyst over other metal catalyst. The catalyst showed moderate to high yield for the hydrogenation of substituted benzoic acid and substituted quinolines. Rh-PVP was recycled four times with a minor loss in catalytic activity.

DOI： 10.1016/j.catcom.2019.02.019

Pt-Co Alloy Nanoparticles on γ-Al <inf>2</inf> O <inf>3</inf> Support: Synergistic Effect between Isolated Erectron-rich Pt and Co for Purification of Automotive Exhaust Reviewed

Sato K, Ito A, Tomonaga H, Kanematsu H, Wada Y, Asakura H, Hosokawa S, Tanaka T, Toriyama T, Yamamoto T, Matsumura S, Nagaoka K

ChemPlusChem Vol. 84 ( 5 ) page： 447 - 456 2019.5

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim There is interest in minimizing or eliminating the use of Pt in catalysts by replacing it with more widely abundant and cost-effective elements. The alloying of Pt with non-noble metals is a potential strategy for reducing Pt use because interactions between Pt and non-noble metals can modify the catalyst structure and electronic properties. Here, a γ-Al2O3-supported bimetallic catalyst [Pt(0.1)Co(1)/Al2O3] was prepared which contained 0.1 wt % Pt and 1 wt % Co and thus featured an extremely low Pt : Co ratio (<1 : 30 mol/mol). The Pt and Co in this catalyst formed alloy nanoparticles in which isolated electron-rich Pt atoms were present on the nanoparticle surface. The activity of this Pt(0.1)Co(1)/Al2O3 catalyst for the purification of automotive exhaust was comparable to the activities of 0.3 and 0.5 wt % Pt/γ-Al2O3 catalysts. Electron-rich Pt and metallic Co promoted activation of NOx and oxidization of CO and hydrocarbons, respectively. This strategy of tuning the surrounding structure and electronic state of a noble metal by alloying it with an excess of a non-noble metal will enable reduced noble metal use in catalysts for exhaust purification and other environmentally important reactions.

DOI： 10.1002/cplu.201800542

Other Link： http://orcid.org/0000-0002-3998-7012

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