Ammonia synthesis on graphitic-nanofilament supported Ru catalysts

Li, Zhonglai; Liang, Changhai; Feng, Zhaochi; Ying, Pinliang; Wang, Dezheng; Li, Can

doi:10.1016/j.molcata.2003.09.028

Cited by 41 publications

(10 citation statements)

References 31 publications

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“…It is known that Pt easily dissociates H 2 which would cover the Ru surface by H making it inaccessible for N 2 dissociation. These results (ammonia synthesis rate, mmol NH 3 h −1 g −1 Ru) are as good as or better than some results obtained on inorganic oxides supports [54–55] but less (≈10×) than some results reported with carbon nanotubes and nanofibers in the literature [43,56–57] using different experimental catalytic testing conditions. This allows for a benchmark for our systems and shows that they are not yet highly performing.…”

Section: Resultssupporting

confidence: 65%

Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

Vidick¹,

Ke²,

Devillers³

et al. 2015

Beilstein J. Nanotechnol.

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SummaryHeterometal clusters containing Ru and Au, Co and/or Pt are anchored onto carbon nanotubes and nanofibers functionalized with chelating phosphine groups. The cluster anchoring yield is related to the amount of phosphine groups available on the nanocarbon surface. The ligands of the anchored molecular species are then removed by gentle thermal treatment in order to form nanoparticles. In the case of Au-containing clusters, removal of gold atoms from the clusters and agglomeration leads to a bimodal distribution of nanoparticles at the nanocarbon surface. In the case of Ru–Pt species, anchoring occurs without reorganization through a ligand exchange mechanism. After thermal treatment, ultrasmall (1–3 nm) bimetal Ru–Pt nanoparticles are formed on the surface of the nanocarbons. Characterization by high resolution transmission electron microscopy (HRTEM) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) confirms their bimetal nature on the nanoscale. The obtained bimetal nanoparticles supported on nanocarbon were tested as catalysts in ammonia synthesis and are shown to be active at low temperature and atmospheric pressure with very low Ru loading.

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Section: Resultssupporting

confidence: 65%

Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

Vidick¹,

Ke²,

Devillers³

et al. 2015

Beilstein J. Nanotechnol.

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“…Figure 6 shows that the rate of ammonia synthesis over the Cs-Ru catalysts was influenced by the reaction temperature and the type of carbon material used as the supporting material. The rates of ammonia synthesis over 2.5Cs-10Ru/AC, 2.5Cs-10Ru/MPC-15, 2.5Cs-10Ru/MPC-18 and 2.5Cs-10Ru/MPC-21 reached their maximum values of 2.2 mmol g −1 h −1 at 400 • C, 8.1 mmol g −1 h −1 at 370 • C, 10.2 mmol g −1 h −1 at 360 • C and 7.3 mmol g −1 h −1 at 360 • C, respectively; however, the rates decreased beyond these temperatures as the reverse reaction of ammonia decomposition can occur rapidly [51]. The three mesoporous 2.5Cs-10Ru/MPC catalysts yielded higher rates for ammonia synthesis at lower reaction temperatures, in comparison to the microporous 2.5Cs-10Ru/AC catalyst.…”

Section: Mild Ammonia Synthesismentioning

confidence: 98%

Energy Efficient and Intermittently Variable Ammonia Synthesis over Mesoporous Carbon-Supported Cs-Ru Nanocatalysts

2019

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The Cs-promoted Ru nanocatalysts supported on mesoporous carbon materials (denoted as Cs-Ru/MPC) and microporous activated carbon materials (denoted as Cs-Ru/AC) were prepared for the sustainable synthesis of ammonia under mild reaction conditions (<500 °C, 1 MPa). Both Ru and Cs species were homogeneously impregnated into the mesostructures of three commercial available mesoporous carbon materials annealed at 1500, 1800 and 2100 °C (termed MPC-15, MPC-18 and MPC-21, respectively), resulting in a series of Cs-Ru/MPC catalysts with Ru loadings of 2.5–10 wt % and a fixed Cs loading of 33 wt %, corresponding to Cs/Ru molar ratios of 2.5–10. However, the Ru and Cs species are larger than the pore mouths of microporous activated carbon (shortly termed AC) and, as a consequence, were mostly aggregated on the outer surface of the Cs-Ru/AC catalysts. The Cs-Ru/MPC catalysts are superior to the Cs-Ru/AC catalyst in catalysing mild ammonia synthesis, especially for the 2.5Cs-10Ru/MPC-18 catalyst with a Ru loading of 10 wt % and a Cs/Ru ratio of 2.5, which exhibited the highest activity across a wide SV range. It also showed an excellent response and stability during cycling tests over a severe temperature jump in a short time, presumably due to the open mesoporous carbon framework and suitable surface concentrations of CsOH and metallic Ru species at the catalytically active sites. This 2.5Cs-10Ru/MPC-18 catalyst with high activity, fast responsibility and good stability has potential application in intermittently variable ammonia synthesis using CO2-free hydrogen derived from electrolysis of water using renewable energy with fast variability.

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“…Ru/activated carbon catalyst has high performance, but a part of the carbon reacts with H2 to give CH4 during long run reactions 45) . Figure 18 shows the TPR patterns of Ru/O-Dia and Ru/activated carbon catalyses.…”

Section: Ammonia Synthesis Catalyzed With O-diamentioning

confidence: 99%

Oxidized Diamond: Novel Catalyst Support Material for Various Catalytic Reactions

Suzuki

Nakagawa

2011

J. Jpn. Petrol. Inst.

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As a new catalyst support, powdered diamond was first investigated. Although diamond has been considered to be a stable material, the surface carbon was found to react to give C _ H and C _ O _ C or C=O bonds by hydrogenation and oxidation. Oxygen treated diamond (O-Dia) was evaluated as a catalyst support material, which was considered to be a pseudo solid carbon oxide phase corresponding to the well known catalyst support SiO2. Following reactions were successfully carried out using O-Dia supported metal oxides or metal catalysts: Dehydrogenation of light alkanes and ethylbenzene to give light alkenes and styrene on Cr2O3 and V2O5/O-Dia catalysts; direct oxidation of C2H6 and CH4 to aldehydes using CO2 as the oxidant over V2O5/O-Dia catalyst; oxidation of methane to syn-gas over Ni or Co/O-Dia catalysts; carbon nanofilament or nanotube synthesis over Ni and Pd/O-Dia catalysts; ammonia synthesis over Ru/O-Dia catalyst. This review article summarizes the characteristics of these reactions.

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Ammonia synthesis on graphitic-nanofilament supported Ru catalysts

Cited by 41 publications

References 31 publications

Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

Energy Efficient and Intermittently Variable Ammonia Synthesis over Mesoporous Carbon-Supported Cs-Ru Nanocatalysts

Oxidized Diamond: Novel Catalyst Support Material for Various Catalytic Reactions

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