Pd and S binding energies and Auger parameters on a model silica-supported Suzuki–Miyaura catalyst: Insights into catalyst activation

Hanif, Mohammad; Ebralidze, Iraklii I.; Horton, J. Hugh

doi:10.1016/j.apsusc.2013.05.070

Cited by 15 publications

(8 citation statements)

References 43 publications

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“…A significant shift toward higher binding energies was observed for Pd 3d 3/2 and 3d 5/2 (i.e., 342.9 and 337.6 eV, respectively), in comparison to those of PdCl 2 , which indicates the formation of Pd(II)–thiolate complexes (Figure ). The optical spectrum of the as-prepared Pd/(SH)MSC was similar to that of the pristine Pd-free composite. The two typical absorbance peaks at ca.…”

Section: Discussionmentioning

confidence: 66%

Poison Tolerance to the Selective Hydrogenation of Cinnamaldehyde in Water over an Ordered Mesoporous Carbonaceous Composite Supported Pd Catalyst

Chen

et al. 2017

ACS Catal.

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A coordination-assisted pyrolysis procedure was adopted to encapsulate palladium (Pd) nanoparticles in a mesoporous carbonaceous matrix. X-ray diffraction and transmission electron microscopy measurements revealed that approximately 2.5 nm nanoparticles were highly dispersed inside the well-ordered porous framework. High-resolution TEM and temperature-programmed hydride decomposition analysis demonstrated the formation of interstitial carbon in the Pd lattice. Diffuse reflectance infrared Fourier transform spectroscopy indicated that carbon species could be deposited on low-coordinated surface sites of the Pd particles. This catalyst exhibited high activity in the selective hydrogenation of cinnamaldehyde (CAL) at 80 °C under an H2 pressure of 1.0 MPa (turnover frequency (TOF) of 2.4 s–1) to produce hydrocinnamyl aldehyde with high selectivity (HCAL; approximately 80%) in water and could be reused eight times with no clear activity loss. A trapping agent poisoning experiment using solid SH-SBA-15 revealed unobvious leaching of Pd into the solution. Exposure to thiourea with a S:Pd ratio of 0.1 resulted in slight activity and undetectable selectivity losses over the current catalyst in the selective hydrogenation of CAL at 80 °C under an H2 pressure of 1.0 MPa. However, a 50% activity loss was observed for commercial Pd/C. Even after an increase in the thiourea concentration to a S:Pd ratio of 3, the TOF remained at 1.9 s–1 with a negligible effect on the HCAL selectivity. Nearly complete deactivation of Pd/C occurred upon high exposure to thiourea. DFT calculations showed that the presence of surface or subsurface carbon can enhance the poison tolerance of the encapsulated Pd catalysts. The enhanced hydrogenation activity and strong poison tolerance are consistent with the interpretation that Pd nanoparticles are modified by carbonaceous deposits.

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Section: Discussionmentioning

confidence: 66%

Poison Tolerance to the Selective Hydrogenation of Cinnamaldehyde in Water over an Ordered Mesoporous Carbonaceous Composite Supported Pd Catalyst

Chen

et al. 2017

ACS Catal.

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“…The most effective catalyst is that which is least prone to the undesirable leaching of Pd: i.e., in which the formation of metallic Pd in the form of nanoparticles is minimized and the number of S-bound Pd species on the surface is maximized. 144 In the presence of PCy 3 , complex 76 shows excellent catalytic activity comparable to that of 71 for Suzuki coupling of a range of deactivated, nonactivated, and activated aryl chloride substrates using 1,4-dioxane as solvent and Cs 2 CO 3 as base. 111 In order to gain insight into the process, the reaction between PCy 3 and 76 (Scheme 6) was carried out.…”

Section: ■ Miscellaneous Palladium Speciesmentioning

confidence: 97%

Formation and Role of Palladium Chalcogenide and Other Species in Suzuki–Miyaura and Heck C–C Coupling Reactions Catalyzed with Palladium(II) Complexes of Organochalcogen Ligands: Realities and Speculations

et al. 2013

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Palladium(II) complexes of organochalcogen ligands have emerged as viable alternatives to complexes of phosphine/carbene ligands for Suzuki−Miyaura and Heck C−C cross coupling reactions, as thermal stability and air and moisture sensitivity are not impediments with many of them. Sometimes they outperform their phosphorus analogues. The ease in handling and synthesis of palladium(II) complexes of organochalcogen ligands has made them attractive. For such complexes in situ generation of palladium containing nanoparticles (NPs) or palladium(0) species and their role in catalysis have been reported. However, in a large number of reports such species are ill defined or speculated, particularly due to limited experimental investigations. Recently in some cases in situ generated palladium species have been studied in detail to establish their identities, which appear to be palladium chalcogenides phases or Pd(0) protected with organochalcogen fragments. In this review the current status regarding in situ generated such species is summarized and critically analyzed to demarcate realities from speculative propositions.

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“…A single S2s peak is observed at 227.7 eV that matches to previously reported for thiol group bonded to a metal surface. 49 Neither “free” thiol nor oxidized sulfur species were found. A single N1s peak at 399.9 eV is consistent with N1s binding energy of 400.0 eV reported for similar aromatic amines.…”

Section: Resultsmentioning

confidence: 99%

Hemoglobin-driven iron-directed assembly of gold nanoparticles

et al. 2018

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Pd and S binding energies and Auger parameters on a model silica-supported Suzuki–Miyaura catalyst: Insights into catalyst activation

Cited by 15 publications

References 43 publications

Poison Tolerance to the Selective Hydrogenation of Cinnamaldehyde in Water over an Ordered Mesoporous Carbonaceous Composite Supported Pd Catalyst

Poison Tolerance to the Selective Hydrogenation of Cinnamaldehyde in Water over an Ordered Mesoporous Carbonaceous Composite Supported Pd Catalyst

Formation and Role of Palladium Chalcogenide and Other Species in Suzuki–Miyaura and Heck C–C Coupling Reactions Catalyzed with Palladium(II) Complexes of Organochalcogen Ligands: Realities and Speculations

Hemoglobin-driven iron-directed assembly of gold nanoparticles

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