Deactivation of Pd/C catalysts by irreversible loss of hydrogen spillover ability of the carbon support

Vanoye, Laurent; Guicheret, Boris; Rivera‐Cárcamo, Camila; Audevard, Jérémy; Navarro‐Ruiz, Javier; Rosal, Iker del; Gerber, Iann C.; Campos, Cristian H.; Machado, Bruno F.; Philippe, Régis; Serp, Philippe; Favre‐Réguillon, Alain

doi:10.1016/j.jcat.2023.05.006

Cited by 8 publications

(15 citation statements)

References 86 publications

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“…The characteristic Bragg peaks of Al 2 O 3 are observed at approximately 19.85° (111), 32.8° (220), 37.5° (011), 39.2° (222), 45.7° (400), 60.3° (511) and 67.39° (440) in the P‐XRD pattern [21] . The only new Bragg peak observed at ~39.7° in the P‐XRD pattern of Pd/Al 2 O 3 catalyst confirms the incorporation of Pd into the structure since it belongs to the Pd (111) plane [22–24] …”

Section: Resultsmentioning

confidence: 77%

“…[21] The only new Bragg peak observed at ~39.7°in the P-XRD pattern of Pd/Al 2 O 3 catalyst confirms the incorporation of Pd into the structure since it belongs to the Pd (111) plane. [22][23][24] SEM and EDX-mapping analyses were performed to examine the morphological structure and elemental distribution of the Pd/Al 2 O 3 catalyst. It clearly shows that the entire surface of Pd/Al 2 O 3 is composed of Pd, Al, and O elements, and the Pd particles are uniformly distributed on the Al 2 O 3 surface as shown in Figure 2(a-f).…”

Section: Resultsmentioning

confidence: 99%

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Hydrogen Production from Morpholine−Borane by Aluminum Oxide‐Supported Pd Nanoparticles

Oğuzyer,

Yurderi,

Zahmakıran

et al. 2023

ChemistrySelect

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Morpholine−borane (MB) is a promising hydrogen storage material and developing effective catalysts for the catalytic hydrolysis reaction of MB has become a fascinating topic in catalysis. Here, we report the preparation of Al2O3‐supported Pd nanoparticles (Pd/Al2O3) by an impregnation‐reduction method and their utilization as catalysts in the catalytic hydrolysis reaction of MB for hydrogen (H2) production. These Pd/Al2O3 are characterized by a combination of several advanced analytical techniques. Pd/Al2O3 catalysts with a mean diameter of 3.12±0.35 nm provide H2 production with a turnover frequency (TOF) value of 495.3 mol(H2) ⋅ molPd−1 ⋅ h−1 in the hydrolysis of MB in complete conversion at 298 K. Additionally, the activation energy (Ea#), activation enthalpy (ΔH#), and activation entropy (ΔS#) values of Pd/Al2O3 catalysts in the hydrolysis reaction of MB are calculated as 30.36 kJ ⋅ mol−1, 28.42 kJ ⋅ mol−1, and −158.52 J ⋅ mol−1 ⋅ K−1, respectively, from Arrhenius and Eyring‐Polanyi equations.

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Section: Resultsmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Hydrogen Production from Morpholine−Borane by Aluminum Oxide‐Supported Pd Nanoparticles

Oğuzyer,

Yurderi,

Zahmakıran

et al. 2023

ChemistrySelect

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“…In the Pd 3d core-level XPS, the main peaks of different samples can be divided into six subpeaks, attributed to Pd 0 and Pd 2+ as well as Pd δ+ (2<δ ≤ 4), which is assigned to the electron-depleted palladium atoms resulting from a charge transfer between Pd species and the supports. 71 For the Pd/CN sample, the two subpeaks at 336.1 and 341.1 eV belong to metallic Pd, the two subpeaks at 337.4 and 342.7 eV are attributed to Pd 2+ , and the other two subpeaks at 338.7 and 344.1 eV are assignable to Pd δ+ (Figure 6a). However, all of the Pd 3d peaks of Pd/CN-X display slightly positive shifts with respect to that of Pd/CN (Table S7), suggesting the presence of strong interactions between Pd nanoparticles and supports with carbon vacancies.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…To gain insight into the metal–carrier interaction and the electronic properties of the catalysts, X-ray photoelectron spectroscopy (XPS) is performed (Figure ). In the Pd 3d core-level XPS, the main peaks of different samples can be divided into six subpeaks, attributed to Pd 0 and Pd 2+ as well as Pd δ+ (2<δ ≤ 4), which is assigned to the electron-depleted palladium atoms resulting from a charge transfer between Pd species and the supports . For the Pd/CN sample, the two subpeaks at 336.1 and 341.1 eV belong to metallic Pd, the two subpeaks at 337.4 and 342.7 eV are attributed to Pd 2+ , and the other two subpeaks at 338.7 and 344.1 eV are assignable to Pd δ+ (Figure a).…”

Section: Resultsmentioning

confidence: 99%

Carbon Vacancies in Graphitic Carbon Nitride-Driven High Catalytic Performance of Pd/CN for Phenol-Selective Hydrogenation to Cyclohexanone

Ding,

Gao,

Chen

et al. 2024

ACS Catal.

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A series of modified carbon nitride with a controlled amount of carbon vacancies is prepared successfully by simple acid treatment, and the performances of the corresponding Pd/CN-X catalysts in phenol-selective hydrogenation are investigated. It is found that the Pd/CN-30 catalyst exhibits the highest activity, while Pd/CN-60 shows a very low activity. The characterization of powder X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectra, temperature-programmed desorption of phenol and cyclohexanone, phenol adsorption experiments, and isotope experiment show that the high catalytic activities and selectivity of Pd/CN-30 are related to its relatively high Pd dispersity, high phenol adsorption capacity, and proper hydrophilicity. However, the much lower activity of Pd/CN-60 can be attributed to the existence of competitive adsorption of phenol and water molecules on the catalyst surface and its low hydrogen activation ability due to the support over modification that results in the much stronger hydrophilicity and the near atomic Pd dispersion. In addition, the stability of Pd/CN-X is positively correlated with the carbon vacancy contents due to the strong interaction between the Pd species and the support.

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“…Some of us recently report that such phenomena can contribute to catalyst deactivation during hydrogenation reactions. 77 3.1.4. Influence of Oxygen-Containing Functional Groups on H-Spillover on Pd/CNT.…”

Section: Characterization Of the Pd-doped Cntsmentioning

confidence: 99%

Mechanism of Hydrogen Spillover on Metal-Doped Carbon Materials: Surface Carboxylic Groups Are Key

Navarro-Ruiz,

Audevard,

Vidal

et al. 2024

ACS Catal.

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Hydrogen spillover (H-spillover) is the surface migration of activated hydrogen atoms from a metallic particle on which they are generated onto a support. The phenomenon has been widely studied because of its implication in hydrogen storage and in catalytic reactions involving hydrogen. Its existence on carbon materials is well established, but questions remain regarding its mechanism and the involvement of surface oxygen groups. In this study, we combined experimental work with chemical modeling to study the mechanisms of H-spillover on a representative system, including a carbon material presenting basal and prismatic surfaces: oxidized carbon nanotubes doped with Pd. The experimental results, supported by those of modeling, show that the surface carboxylic acid groups are the key species, allowing the spillover of hydrogen on carbon materials to take place. The carboxylic groups can also work in combination with phenol groups to facilitate H-spillover. If the concentration of these groups is too low, then the H-spillover does not operate, except in the case of the addition of water, which serves as a shuttle for the protons. This study leads to a deeper understanding of the long-debated issue of H-spillover on carbon materials and provides insight into designing systems with enhanced properties.

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Deactivation of Pd/C catalysts by irreversible loss of hydrogen spillover ability of the carbon support

Cited by 8 publications

References 86 publications

Hydrogen Production from Morpholine−Borane by Aluminum Oxide‐Supported Pd Nanoparticles

Hydrogen Production from Morpholine−Borane by Aluminum Oxide‐Supported Pd Nanoparticles

Carbon Vacancies in Graphitic Carbon Nitride-Driven High Catalytic Performance of Pd/CN for Phenol-Selective Hydrogenation to Cyclohexanone

Mechanism of Hydrogen Spillover on Metal-Doped Carbon Materials: Surface Carboxylic Groups Are Key

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