Influence of chemical treatments of activated carbon support on the performance and deactivation behavior of promoted Ru catalyst in ammonia synthesis

Jafari, Ali; Saadatjou, Naghi; Sahebdelfar, Saeed

doi:10.1016/j.ijhydene.2015.01.071

Cited by 18 publications

(8 citation statements)

References 38 publications

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“…26−30 The small Ru particles over HSAG are not attributed to the surface area as the specific surface area is determined to be 400 m 2 /g, which is significantly lower than that of activated carbon. 10 In addition, as evidenced in Figure S1, no clear morphology change is detected. We suggest that the unique interaction of the Ru precursor or Ru with HSAG is responsible for the uniform dispersion.…”

Section: ■ Results and Discussionmentioning

confidence: 84%

“…Interestingly, via simple mixing, sub-nano Ru particles over HSAG are obtained with uniform distribution (Figure d). Usually, even with impregnation, Ru particle size ranges from 3 to 15 nm are obtained over various supports. − The small Ru particles over HSAG are not attributed to the surface area as the specific surface area is determined to be 400 m 2 /g, which is significantly lower than that of activated carbon . In addition, as evidenced in Figure S1, no clear morphology change is detected.…”

Section: Resultsmentioning

confidence: 98%

“…4−9 Among them, activated carbon was confirmed to be one of the most effective supports. 10 However, the chemical and physical properties pose significant challenges for the development of Ru catalysts for ammonia synthesis.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Although the catalytic ammonia synthesis was discovered more than 100 years ago, it is still a “never ending story” . After well consolidated iron catalysts, ruthenium is considered to be the new generation of ammonia synthesis catalysts which show much higher activity. , Since the discovery of Ru catalysts, various supports have been tested, such as Al 2 O 3 , MgO, zeolite, BaTiO 3 , C 3 N 4 , and BN. − Among them, activated carbon was confirmed to be one of the most effective supports . However, the chemical and physical properties pose significant challenges for the development of Ru catalysts for ammonia synthesis.…”

Section: Introductionmentioning

confidence: 99%

“…Second, activated carbon usually contains small amounts of ash which is unfavorable for the activity of catalysts. Therefore, prior to the loading of Ru, treatment of activated carbons with HNO 3 is usually suggested. , In addition, hydrogen treatment at high temperatures was found to be effective for the improvement of activity as it removes the elements such as P and Cl which function as poisons for ammonia synthesis . Third, it is well accepted that ammonia synthesis over Ru is a structure-sensitive reaction.…”

Section: Introductionmentioning

confidence: 99%

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Strong Interaction of Ruthenium Species with Graphite Structure for the Self-Dispersion of Ru under Solvent-Free Conditions

Han

Yan

et al. 2017

ACS Sustainable Chem. Eng.

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Carbon materials-supported Ru catalysts are some of the most efficient catalysts for ammonia synthesis. Usually they are prepared by impregnation for the dispersion of the Ru metal. In the present study, we report that a strong interaction of ruthenium species (with triruthenium dodecacarbonyl as the precursor) with a graphite structure enables the self-dispersion of Ru under solvent-free conditions. Via simple mixing and heat treatment, sub-nano Ru particles over high surface area graphite (HSAG) are obtained with uniform distribution. The ammonia yields or ammonia synthesis rate is almost 50% higher than the catalysts prepared via impregnation whether the support is activated carbon or HSAG. During catalyst preparation, Ru3(CO)12 is adsorbed on the surface of HSAG via CO groups in Ru3(CO)12 and surface oxygen groups on HSAG. Subsequently, Ru3(CO)12 undergoes decarbonylation reaction at very low temperatures. Then, CO has a dismutation reaction over the Ru surface leading to the formation of RuO2 at temperatures between 180 and 190 °C. During heat treatment, RuO2 was partially reduced by carbon at elevated temperatures, and the resulting Ru has strong interaction with HSAG, which further leads to the dispersion and stabilization of Ru nanoparticles.

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Section: ■ Results and Discussionmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 98%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Strong Interaction of Ruthenium Species with Graphite Structure for the Self-Dispersion of Ru under Solvent-Free Conditions

Han

Yan

et al. 2017

ACS Sustainable Chem. Eng.

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Carboxymethylcellulose template synthesis of porous aluminium oxide from hybrid spheres: influence of the degree of substitution and polymerization

et al. 2016

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Catalytic supports based on aluminum oxide were synthesized by the method of hybrid spheres using carboxymethylcellulose as organic precursor (template) and aluminum nitrate as inorganic precursor. The characterizations were performed by analysis of TG, XRD, FTIR, SEM and N 2 physisorption. The study of synthesis indicated that the characteristics of the biopolymer (degree of substitution and polymerization) directly influence on the limit ratio between organic and inorganic precursor in order to observe the formation of the hybrid spheres. The physicochemical properties of the final material (structure by XRD, texture by N 2 physisorption and morphology by SEM) showed a direct dependence with the biopolymer properties, indicating the versatility of this synthetic route. FTIR spectra confirm the formation of a hybrid material, comparing the pure CMC spectrum with the solids after drying. N 2 adsorption/desorption isotherm and SEM images confirm the formation of highly porous materials with a specific surface area between 50 and 162 m 2 /g.

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Effect of iron oxide precursor on the properties and ammonia synthesis activity of fused iron catalysts

Jafari¹,

Ebadi²,

Sahebdelfar³

2018

Reac Kinet Mech Cat

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Influence of chemical treatments of activated carbon support on the performance and deactivation behavior of promoted Ru catalyst in ammonia synthesis

Cited by 18 publications

References 38 publications

Strong Interaction of Ruthenium Species with Graphite Structure for the Self-Dispersion of Ru under Solvent-Free Conditions

Strong Interaction of Ruthenium Species with Graphite Structure for the Self-Dispersion of Ru under Solvent-Free Conditions

Carboxymethylcellulose template synthesis of porous aluminium oxide from hybrid spheres: influence of the degree of substitution and polymerization

Effect of iron oxide precursor on the properties and ammonia synthesis activity of fused iron catalysts

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