Palladium supported on structured and nonstructured carbon: A consideration of Pd particle size and the nature of reactive hydrogen

Amorim, Cláudia; Keane, Mark A.

doi:10.1016/j.jcis.2008.02.021

Cited by 158 publications

(102 citation statements)

References 93 publications

(201 reference statements)

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“…33 As shown in Figure 3, only a negative peak centered at 348 K appears in the TPR profile indicating hydrogen evolution which is attributed to the Pd β-hydride decomposition. 34 Moreover, the amount of hydrogen evolved from the individual peaks was in accordance with the trend of the corresponding Pd average particle size. Santacesaria et al 1 reported that the overall reaction rate of anthraquinone hydrogenation was dominated by the mass transfer rate, while in the same reaction condition the difference of mass transfer was negligible.…”

Section: Characterizationsupporting

confidence: 62%

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Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al₂O₃Catalyst

Li¹,

Su²,

Ren³

et al. 2016

Journal of the Brazilian Chemical Society

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A series of highly dispersed Pd/Al 2 O 3 catalysts were prepared via the polyol method. The catalysts were characterized by nitrogen adsorption, X-ray diffraction (XRD), UV-Vis spectrophotometry, temperature programmed reduction (TPR) and transmission electron microscopy (TEM). The influence of Pd particle size on the hydrogenation of 2-amyl anthraquinone (AAQ) was investigated in a trickle-bed reactor. The turnover frequency (TOF) showed antipathetic size dependence while the space time yield (STY) peaked at 4 nm. Also, the selectivity and deactivation rate were affected by the size of palladium particles. The structure-sensitivity relations for the catalysts may be ascribed to the necessities of specific Pd cluster structure for the activation of π-bond. Keywords: anthraquinone hydrogenation, H 2 O 2 , dispersion IntroductionHydrogen peroxide (H 2 O 2 ) is widely used in the chemical industry and environmental protection as an environmentally friendly oxidant. [1][2][3] Today, hydrogen peroxide is manufactured almost exclusively by the autoxidation of 2-alkyl anthrahydroquinone (2-alkyl AQH 2 ) to the corresponding 2-alkyl anthraquinone (2-alkyl AQ) in the so-called AQ process. In the cyclic process, AQ is hydrogenated to yield anthrahydroquinone, then oxidation of the latter produces hydrogen peroxide and regenerates the starting AQ (Scheme 1). 4 Major producers commonly use either the 2-ethyl or the 2-amyl derivative of AQ. In recent years, along with the production growth of downstream products such as propylene oxide and caprolactam, the market demand for H 2 O 2 solution at high concentration has been increasing substantially. Given its high solubility, 2-amylanthraquinone is considered as a good replacement for the widely used 2-ethylanthraquinone to increase productivity. 5 The network of the reactions taking place during the hydrogenation of 2-amyl anthraquinone (AAQ) is quite complicated. The desired products considered as active anthraquinones are 2-amyl anthrahydroquinone (AAQH 2 ) and 2-amyl tetrahydroanthrahydroquinone (H 4 AAQH 2 ), which could produce H 2 O 2 after oxidation. However, other degradations such as 2-amyl octahydroanthrahydroquinone (H 8 AAQH 2 ) and anthrone (AN) are useless to the H 2 O 2 production.6 Previous literature about the hydrogenation of anthraquinone used the 2-ethyl-anthraquinone (EAQ) system rather than the 2-amylanthraquinone system. In addition, the research focused on the topics such as the enhancement of mass transfer and the properties of support. For example, Santacesaria et al. 7 reported that the hydrogenation of 2-ethyl-anthraquinone over Pd catalysts was a fast reaction and the mass transfer of EAQ was the rate limiting step. Based on this, Luo and co-workers 8 designed an egg shell Pd/glass catalyst which can achieve a high instant yield of H 2 O 2 of 11.2 g L -1. Besides, the acid-base property of the support was a key point to influence the catalyst activity and selectivity, as the acid sites of the support were considered as the adsorption sites of EAQ...

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Section: Characterizationsupporting

confidence: 62%

supporting

confidence: 62%

Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al₂O₃Catalyst

Li¹,

Su²,

Ren³

et al. 2016

Journal of the Brazilian Chemical Society

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“…Palladium-supported activated carbon (Pd/AC) is commonly used as a catalyst in numerous reactions, including the reduction of organics with gaseous hydrogen [1][2][3][4][5][6], hydrodehalogenation [7][8][9], alcohol oxidation [10], and oxygen electroreduction [11]. The catalytic activity of the Pd/AC system depends both on the properties of the palladium particle size/dispersion and the nature of the carbon support surface [6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…The catalytic activity of the Pd/AC system depends both on the properties of the palladium particle size/dispersion and the nature of the carbon support surface [6][7][8][9][10][11][12]. The carbon support causes notable excitations in the electronic structure of metal atoms directly bound to the surface (donor-acceptor interaction with the aromatic p system) [13].…”

Section: Introductionmentioning

confidence: 99%

Reduction and oxidation of a Pd/activated carbon catalyst: evaluation of effects

Biniak

Diduszko

Gac

et al. 2010

Reac Kinet Mech Cat

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A commercial Pd/activated carbon catalyst (10%) was treated using several redox processes: reduction with gaseous hydrogen at 140°C, reduction by negative electrochemical polarization in acidic and basic environments, oxidation with aqueous hydrogen peroxide, and positive electrochemical polarization in acidic and basic environments. To establish the electrochemical reduction/oxidation conditions, the potentials of hydrogen and oxygen evolution at Pd/AC powder electrodes were determined from cyclic voltammetric (CV) measurements. The samples were examined for the presence of palladium oxide phases on dispersed metal particles using XRD, TPR, and TPD. The metal oxide phase disappeared following hydrogen and electrochemical reduction. Oxidative treatment of the commercial catalyst differentiated the palladium oxide layers on the metal particle surface. Changes in the surface chemistry of the Pd/PdO/AC system were confirmed by the electrochemical behavior of electrodes prepared from the carbon samples.

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“…We anticipate the desorption species (whether H 2 or H 2 O) will depend not only on the nature of the oxygen functional groups, but also the oxygen groups populated by spilled over hydrogen, which would be dependent upon adsorption temperature. Here, we use temperature programmed desorption (TPD), which has been used extensively for the study of oxygen functional groups 19,23 and spilt-over hydrogen 24,25 . In this section, TPD is employed to identify the desorbed species from various oxygenmodified carbon materials, with an emphasis on H 2 and H 2 O.…”

Section: Main Findings (Conclusion Section Of the Submitted Paper W/mentioning

confidence: 99%

Development of Doped Nanoporous Carbons for Hydrogen Storage

Lueking¹,

Li²,

Badding³

et al. 2010

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Palladium supported on structured and nonstructured carbon: A consideration of Pd particle size and the nature of reactive hydrogen

Cited by 158 publications

References 93 publications

Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al₂O₃Catalyst

Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al₂O₃Catalyst

Reduction and oxidation of a Pd/activated carbon catalyst: evaluation of effects

Development of Doped Nanoporous Carbons for Hydrogen Storage

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Palladium supported on structured and nonstructured carbon: A consideration of Pd particle size and the nature of reactive hydrogen

Cited by 158 publications

References 93 publications

Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al2O3Catalyst

Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al2O3Catalyst

Reduction and oxidation of a Pd/activated carbon catalyst: evaluation of effects

Development of Doped Nanoporous Carbons for Hydrogen Storage

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Product

Resources

About

Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al₂O₃Catalyst

Effect of Metal Dispersion on the Hydrogenation of 2-Amyl Anthraquinone over Pd/Al₂O₃Catalyst