Ammonia synthesis over Ru/C catalysts with different carbon supports promoted by barium and potassium compounds

Liang, Changhai; Wei, Zhimei; Xin, Qin; Li, Can

doi:10.1016/s0926-860x(00)00713-4

Cited by 170 publications

(118 citation statements)

References 31 publications

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“…Indeed, a much lower amount of oxygen was uptaken by the sample treated at 300°C, in line with the hypothesis of partial Ru covering by BaO [5,13,18]. Furthermore, this excludes the reduction of this promoter at least at this temperature.…”

Section: -O2 Chemisorptionsupporting

confidence: 84%

“…Many possible formulations have been proposed, widely differing as for support (mainly active or graphitised carbon [2,[4][5][6]8] and MgO [9][10][11]), Ru precursor (chloride [5,12,13], potassium ruthenate [2], carbonyls [14][15][16], nitrosylnitrate [17,18]) and promoters (alkali-, alkali-earth-and lanthanide-oxides).…”

Section: -Introductionmentioning

confidence: 99%

“…For example, a short activation route has been proposed [2,17], consisting in heating by 1°C/min up to 450°C, then kept for 5 hours, taken as example also by others [5]. By contrast, a much longer activation is reported e.g.…”

Section: -Introductionmentioning

confidence: 99%

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Promoters state and catalyst activation during ammonia synthesis over Ru/C

Rossetti¹,

Mangiarini²,

Forni³

2007

Applied Catalysis A: General

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Carbon-supported, promoted Ru-based catalysts for ammonia synthesis proved to be interesting substitutes for the traditional Fe-based ones. A debate recently arose on the active state of promoters, mainly Cs and Ba, and on the effect of the latter on Ru active sites. In the present work a set of Ba-, Cs-and K-promoted samples has been characterised by various techniques. Higher H2 and O2 uptakes have been observed during reduction and chemisorption, respectively, on Cs-and K-promoted samples supported on graphitised carbon. No evidence of this has been observed with samples supported on active carbon. This is in line with the hypothesis of alkaline promoters partial reduction under the ammonia synthesis conditions, favoured by the formation of graphite intercalation compounds. Furthermore, some suggestions are here introduced on the beneficial role of Ba, especially in increasing the support resistance to methanation.Finally, the efficacy of catalyst activation was found to depend on the nature of Ru precursor. Indeed, a prolonged activation at relatively high temperature is usually needed with chloride precursors, to remove the counterion, a poison for the catalyst, whereas less dramatic conditions are required for different precursors, such as nitrosylnitrate.

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Section: -O2 Chemisorptionsupporting

confidence: 84%

Section: -Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Promoters state and catalyst activation during ammonia synthesis over Ru/C

Rossetti¹,

Mangiarini²,

Forni³

2007

Applied Catalysis A: General

View full text Add to dashboard Cite

show abstract

“…Ammonia synthesis was performed in a stainless steel fixed bed reactor system [8]. For the steady state measurement of catalytic activity, the reactor was filled with the Ru/GNFs catalyst diluted with 20-60 meshes quartz particles as the catalyst bed.…”

Section: Catalytic Activity Testmentioning

confidence: 99%

“…Therefore, a more stable support is required, and this has led to a search for an alternative to active carbon. Recently, a number of studies have shown that graphitzed activated carbon, MgO and BN supported Ru have high catalytic activities and long-term stability for ammonia synthesis [4][5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%