Support and promoter effect of ruthenium catalyst I. Characterization of alkali-promoted ruthenium/alumina catalysts for ammonia synthesis

Aika, Ken‐ichi; Shimazaki, Kozo; Hattori, Yasuyuki; Ohya, A.; Ohshima, Shusuke; Shirota, Koichiro; Ozaki, Atsumu

doi:10.1016/0021-9517(85)90264-7

Cited by 161 publications

(63 citation statements)

References 6 publications

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“…At high conversions and on large surface facets inhibition of activity occurs by adsorbed hydrogen, [25] as also indicated by the leveling off in the particle-size-activity curve of Ru-out in Figure 4. This adverse effect is in line with the faceted shape seen in the TEM images, producing many large flat terraces with a low density of high-energy sites.…”

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confidence: 92%

Structure–Function Correlations for Ru/CNT in the Catalytic Decomposition of Ammonia

et al. 2010

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Electrochemical energy storage is one of the important technologies for a sustainable future of our society, in times of energy crisis. Lithium-ion batteries and supercapacitors with their high energy or power densities, portability, and promising cycling life are the cores of future technologies. This Review describes some materials science aspects on nanocarbon-based materials for these applications. Nanostructuring (decreasing dimensions) and nanoarchitecturing (combining or assembling several nanometer-scale building blocks) are landmarks in the development of high-performance electrodes for with long cycle lifes and high safety. Numerous works reviewed herein have shown higher performances for such electrodes, but mostly give diverse values that show no converging tendency towards future development. The lack of knowledge about interface processes and defect dynamics of electrodes, as well as the missing cooperation between material scientists, electrochemists, and battery engineers, are reasons for the currently widespread trial-and-error strategy of experiments. A concerted action between all of these disciplines is a prerequisite for the future development of electrochemical energy storage devices

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confidence: 92%

Structure–Function Correlations for Ru/CNT in the Catalytic Decomposition of Ammonia

et al. 2010

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“…Ruthenium-based H-B catalysts are also promoted with alkali metals [32]. In general, Ru catalysts exhibit higher activity with larger alkali metals, but recently Li was found to be a competent promoter [6, 37-39]. Analogous studies on alkali metal promoters for Fe catalysts do not always agree on the relative changes in activity when changing the alkali metal [28, 32, 34-36].…”

Section: Introductionmentioning

confidence: 99%

Coordination chemistry insights into the role of alkali metal promoters in dinitrogen reduction

Connor

Holland

2017

Catalysis Today

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The Haber-Bosch process is a major contributor to fixed nitrogen that supports the world's nutritional needs and is one of the largest-scale industrial processes known. It has also served as a testing ground for chemists’ understanding of surface chemistry. Thus, it is significant that the most thoroughly developed catalysts for N2 reduction use potassium as an electronic promoter. In this review, we discuss the literature on alkali metal cations as promoters for N2 reduction, in the context of the growing knowledge about cooperative interactions between N2, transition metals, and alkali metals in coordination compounds. Because the structures and properties are easier to characterize in these compounds, they give useful information on alkali metal interactions with N2. Here, we review a variety of interactions, with emphasis on recent work on iron complexes by the authors. Finally, we draw conclusions about the nature of these interactions and areas for future research.

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“…In the case of the RuCl 3 /MgO and RuCl 3 /CA samples, peaks for H 2 consumption,H 2 O, and 35 Cl desorption were observed at the same position: 380 8Cf or RuCl 3 /MgO and 210 8Cf or RuCl 3 /CA. These resultsi ndicatet hat Cl À ions on the catalysts urfacea re removed as HCl during the reduction treatment in aH 2 atmosphere according to Equation (1): [7]…”

Section: Resultsmentioning

confidence: 93%

“…[5] It is recognized that the catalytic activity of Ru is enhanced strongly by the addition of alkali or alkaline earth compounds with electron-donating properties;t hat is, the N 2 dissociation reaction, which is the rate-determining step of ammonias ynthesis, is promoted by the injection of electrons from the promotert oN 2 over Ru catalyst. [6][7][8][9][10] In contrast, small amountso fi mpuritiess uch as SO 4 2À ,C l À ,F À ,a nd PO 4 3À are strong inhibitors of Ru catalysts for ammonia synthesis and decomposition. [5,11] The presence of these electron-withdraw-ing groups decreases the catalytic activity significantly and increasest he activation energy for ammonia synthesis.…”

Section: Introductionmentioning

confidence: 99%

Chlorine‐Tolerant Ruthenium Catalyst Derived Using the Unique Anion‐Exchange Properties of 12 CaO⋅7 Al₂O₃ for Ammonia Synthesis

Jiang

Kitano

et al. 2017

ChemCatChem

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Poisoning is defined as deactivation by the strong adsorption of, usually, impurities on active sites, which is a serious problem in many important catalytic processes. For example, the activity of Ru catalysts is significantly degraded by Cl in ammonia synthesis because of its electron‐withdrawing properties. Here we demonstrate that 12 CaO⋅7 Al2O3 with subnanometer‐sized cages prevents the poisoning of a Ru catalyst by Cl− ions in ammonia synthesis. Conventional supported Ru catalysts exhibit a negligible activity if a tiny amount of Cl− ions remain on the catalyst surface. In contrast, the catalytic activity of Ru/C12A7 is not influenced by Cl− ions even though the amount of Cl in Ru/C12A7 is one order of magnitude higher than that in the conventional Ru catalysts. The Cl resistance of Ru/C12A7 is attributed to the unique anion‐exchange properties of C12A7; that is, the Cl− ions are trapped preferentially in the positively charged subnanometer‐sized cages of C12A7 instead of OH− ions under ammonia synthesis conditions.

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Support and promoter effect of ruthenium catalyst I. Characterization of alkali-promoted ruthenium/alumina catalysts for ammonia synthesis

Cited by 161 publications

References 6 publications

Structure–Function Correlations for Ru/CNT in the Catalytic Decomposition of Ammonia

Structure–Function Correlations for Ru/CNT in the Catalytic Decomposition of Ammonia

Coordination chemistry insights into the role of alkali metal promoters in dinitrogen reduction

Chlorine‐Tolerant Ruthenium Catalyst Derived Using the Unique Anion‐Exchange Properties of 12 CaO⋅7 Al₂O₃ for Ammonia Synthesis

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Support and promoter effect of ruthenium catalyst I. Characterization of alkali-promoted ruthenium/alumina catalysts for ammonia synthesis

Cited by 161 publications

References 6 publications

Structure–Function Correlations for Ru/CNT in the Catalytic Decomposition of Ammonia

Structure–Function Correlations for Ru/CNT in the Catalytic Decomposition of Ammonia

Coordination chemistry insights into the role of alkali metal promoters in dinitrogen reduction

Chlorine‐Tolerant Ruthenium Catalyst Derived Using the Unique Anion‐Exchange Properties of 12 CaO⋅7 Al2O3 for Ammonia Synthesis

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Product

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Chlorine‐Tolerant Ruthenium Catalyst Derived Using the Unique Anion‐Exchange Properties of 12 CaO⋅7 Al₂O₃ for Ammonia Synthesis