Hydrogen spillover effect over the oxide surfaces in supported nickel catalysts

Almăşan, Valer; Gaeumann, T.; Lazăr, Mihaela D.; Mărginean, P.; Aldea, N.

doi:10.1016/s0167-2991(97)80443-0

Cited by 6 publications

(4 citation statements)

References 5 publications

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“…For Al 2 O 3 , the HD evolution peak, peak α, is observed at 645 K, mainly from the hydroxyls, that is, HO–Al. The Ni/Al 2 O 3 shows mainly two evolution peaks at 410 and 457 K: the first peak, that is, the γ peak, is attributed to the chemisorbed hydrogen on the nickel; the second is due to the hydroxyls (α species) of the alumina support, which moves to lower temperatures by the catalysis of the nickel for the dissociation of H 2 . − After the encapsulation of Al 2 O 3 with CN, the peak temperature for H–D exchange is delayed to 765 K, reflecting the hydrogen tightly bonded to CN on Al 2 O 3 , that is, the δ species. Even when the sample was cooled in hydrogen, we could not detect any hydrogen adsorbed on the CN/Al 2 O 3 .…”

Section: Resultsmentioning

confidence: 99%

Acid-Resistant Catalysis without Use of Noble Metals: Carbon Nitride with Underlying Nickel

et al. 2014

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A nanocomposite able to function as a hydrogenation catalyst under strongly acidic conditions without the presence of noble metals is synthesized and thoroughly studied. This specially designed catalyst possesses a unique structure composed of carbon nitride (CN) with underlying nickel, in which the nickel endows the CN with new active sites for hydrogen adsorption and activation while it itself is physically isolated from the reactive environment and protected from poisoning or loss. The CN is inert for hydrogenation without the help of nickel. The catalyst shows good performance for hydrogenation of nitro compounds under strong acidic conditions, including the one-step hydrogenation of nitrobenzene in 1.5 M H 2 SO 4 to produce p-amoniophenol, for which the acid in the reaction system has restricted the catalyst only to noble metals in previous studies. Further characterization has demonstrated that the nickel in the catalyst is in an electron-deficient state because some of its electron has been donated to CN (HRTEM, PES); thus, the hydrogen can be directly adsorbed and activated by the CN (HD exchange, in situ IR and NMR). With this structure, the active nickel is protected by inert CN from the corrosion of acid, and the inert CN is activated by the nickel for catalytic hydrogenation. The assembly of them gives a new catalyst that is effective and stable for hydrogenation even under a strongly acidic environment.

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Section: Resultsmentioning

confidence: 99%

Acid-Resistant Catalysis without Use of Noble Metals: Carbon Nitride with Underlying Nickel

et al. 2014

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“…Carbon monoxide chemisorption measurements at 25 °C were applied for the determination of Ni dispersion and mean particle size using a modified Sorptomatic 1900 apparatus (Fisons Instruments, Glaskow, UK) and assuming a CO:Me stoichiometry of 1:1, an atomic surface area of 6.5 Å 2 and spherical particles. CO chemisorption measurements were used instead of H 2 chemisorption in order to avoid overestimation of Ni dispersion due to hydrogen spillover effects, which have been previously found to occur over supported Ni catalysts [ 26 , 27 ]. Nickel particle size was calculated according to the following equation:

where d N i is the mean crystallite diameter, ρ Ni (= 8.9 g∙cm −3 ) is the density of Ni and S N i [m 2 /g Ni ] is the surface area per gram of Ni.…”

Section: Methodsmentioning

confidence: 99%

Support Effects on the Activity of Ni Catalysts for the Propane Steam Reforming Reaction

2021

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The catalytic performance of supported Ni catalysts for the propane steam reforming reaction was investigated with respect to the nature of the support. It was found that Ni is much more active when supported on ZrO2 or YSZ compared to TiO2, whereas Al2O3- and CeO2-supported catalysts exhibit intermediate performance. The turnover frequency (TOF) of C3H8 conversion increases by more than one order of magnitude in the order Ni/TiO2 < Ni/CeO2 < Ni/Al2O3 < Ni/YSZ < Ni/ZrO2, accompanied by a parallel increase of the selectivity toward the intermediate methane produced. In situ FTIR experiments indicate that CHx species produced via the dissociative adsorption of propane are the key reaction intermediates, with their hydrogenation to CH4 and/or conversion to formates and, eventually, to CO, being favored over the most active Ni/ZrO2 catalyst. Long term stability test showed that Ni/ZrO2 exhibits excellent stability for more than 30 h on stream and thus, it can be considered as a suitable catalyst for the production of H2 via propane steam reforming.

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“…nickel. Although less efficient than Pd because of a stronger M-H bond,[62] carbon-supported Ni catalysts are also active for H-spillover [63][64][65][66]. Figure 3.…”

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confidence: 99%

“Cocktail”-type catalysis on bimetallic systems for cinnamaldehyde selective hydrogenation: Role of isolated single atoms, nanoparticles and single atom alloys

Audevard

Navarro‐Ruiz

Bernardin

et al. 2023

Journal of Catalysis

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Hydrogen spillover effect over the oxide surfaces in supported nickel catalysts

Cited by 6 publications

References 5 publications

Acid-Resistant Catalysis without Use of Noble Metals: Carbon Nitride with Underlying Nickel

Acid-Resistant Catalysis without Use of Noble Metals: Carbon Nitride with Underlying Nickel

Support Effects on the Activity of Ni Catalysts for the Propane Steam Reforming Reaction

“Cocktail”-type catalysis on bimetallic systems for cinnamaldehyde selective hydrogenation: Role of isolated single atoms, nanoparticles and single atom alloys

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