Dihydrogen Activation by Mixed Platinum- and Palladium-Gold Cluster Compounds. Homogeneous Catalytic H2-D2 Equilibration

Aubart, Mark A.; Chandler, Bert D.; Gould, Rachael A. T.; Krogstad, Don A.; Schoondergang, M. F. J.; Pignolet, L. H.

doi:10.1021/ic00095a016

Cited by 46 publications

(75 citation statements)

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“…Finally, the reactivities of the Pt m Au n + ions may be compared with those of related bimetallic clusters. For instance, Aubart et al reported that complexes such as [Pt(AuPPh 3 ) 8 ](NO 3 ) 2 efficiently catalyze H 2 /D 2 equilibration 21, 22. Similar to the present findings, monometallic gold clusters are unreactive.…”

Section: Discussionsupporting

confidence: 89%

“…Although it might well be the case that the activities of bimetallic platinum‐gold clusters differ for reactions with CH 4 and O 2 on the one hand and H 2 /D 2 on the other, it also appears possible that the metal clusters' intrinsic reactivities in the H 2 /D 2 equilibration reactions could be shielded by ligand effects. Aubart et al indicate that a weaker binding of the phosphine ligands to gold atoms might facilitate their dissociation, which is essential for catalyst activation 22. In fact, in a theoretical investigation of H 2 dissociation on bare dimer and trimer platinum–gold clusters, Cruz et al found gold to decrease the clusters' reactivity in agreement with the present results 23.…”

Section: Discussionsupporting

confidence: 86%

“…Similar to the present findings, monometallic gold clusters are unreactive. However, in contrast to the situation for the Pt m Au n + ions, the reactivities of the phosphine‐stabilized clusters increase as a function of gold content 22. Although it might well be the case that the activities of bimetallic platinum‐gold clusters differ for reactions with CH 4 and O 2 on the one hand and H 2 /D 2 on the other, it also appears possible that the metal clusters' intrinsic reactivities in the H 2 /D 2 equilibration reactions could be shielded by ligand effects.…”

Section: Discussionmentioning

confidence: 72%

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Additivity Effects in the Reactivities of Bimetallic Cluster Ions Pt_mAu_n⁺

2003

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All that glitters…︁The gas‐phase reactions of the bimetallic cluster ions PtmAun+ (m+n≤4) with dioxygen and methane are investigated. The platinum‐rich cluster ions undergo degradation processes and dehydrogenation reactions, which are also known for pure Ptm+ clusters. In contrast, the gold‐rich cluster ions are found to be unreactive, similar to the corresponding Aum+ clusters. This distinct trend in reactivity (see graphic) is correlated with the systems' electronic properties changing as a function of cluster composition.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 72%

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Additivity Effects in the Reactivities of Bimetallic Cluster Ions Pt_mAu_n⁺

2003

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“…There are a number of reports on the synthesis of bimetallic nanoparticles of Au and Pd using PAMAM dendrimers and other techniques. − Ozturk et al studied the decomposition pattern of PAMAM dendrimer and reported that temperatures as high as 400 °C are required for complete removal of dendrimers . Another study conducted by Lang et al also showed using in-situ infrared spectroscopy that the complete removal of the dendrimer takes place at temperature above 300 °C .…”

Section: Introductionmentioning

confidence: 99%

Synergistic Effects of Gold–Palladium Nanoalloys and Reducible Supports on the Catalytic Reduction of 4-Nitrophenol

et al. 2017

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Herein we report on the catalytic activity of mesoporous nickel, iron, cerium, cobalt, and manganese oxides prepared using KIT-6 as a hard template via evaporation-assisted precipitation. The mesoporous metal oxides (MMOs) were characterized and used as heterogeneous catalysts in the reduction of 4-nitrophenol (4-Nip) by sodium borohydride (BH4 –). Furthermore, polyamidoamide (PAMAM) dendrimers were used to synthesize gold–palladium nanoalloy particles. The size of AuPd/PAMAM was found to be 3.5 ± 0.8 nm in diameter before being immobilized on the aforementioned mesoporous metal oxides and used as catalysts in the reduction of 4-Nip. Prior to catalytic evaluation, the reduction profiles of the mesoporous metal oxides were investigated by hydrogen-temperature-programmed reduction (H2-TPR) and showed that mesoporous metal oxides can be easily reduced at lower temperatures and that the immobilization of gold–palladium nanoalloy particles lowers their reduction temperatures. Mesoporous cobalt and manganese oxides showed catalytic activity toward 4-Nip reduction, and the activity was enhanced after immobilization of the gold–palladium nanoalloys. Isolation of nanoparticles activity was achieved by immobilization of the gold–palladium nanoalloys on the inert silica support. From this we postulated an electron relay mechanism for the reduction of 4-nitrophenol. With the use of power rate law we showed that 4-Nip reduction follows pseudo-first-order kinetics.

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“…These clusters are very well characterized in solid (single-crystal X-ray diffraction) and solution (NMR, IR, UV−visible spectroscopy) phases. − The solid-state structures of the metal cores of 1 − 3 are shown in Figure . The reaction chemistry of 16-electron clusters 1 and 2 with H 2 and CO has been thoroughly investigated. ,, Both react with one molecule of CO (1 atm) quantitatively in solution and solid phases to give the 18-electron adducts [(CO)Pt(AuPPh 3 ) 8 ](NO 3 ) 2 ( 1(CO) ) and [(PPh 3 )(CO)Pt(AuPPh 3 ) 6 ](NO 3 ) 2 ( 2(CO) ), respectively.…”

Section: Introductionmentioning

confidence: 99%

Cluster Chemistry on Surfaces: Characterization and Catalytic Studies of Phosphine-Stabilized Platinum−Gold Clusters on Silica and Alumina Supports

et al. 1996

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Cationic, phosphine-ligated Pt−Au cluster compounds, [Pt(AuPPh3)8](NO3)2 (1) and [(PPh3)Pt(AuPPh3)6](NO3)2 (2), have been immobilized on silica and alumina supports. Characterization of the supported clusters by 31P MAS NMR, IR, and UV−visible spectroscopy and study by chemisorption and temperature-programmed desorption of CO show that the clusters are immobilized intact without measurable fragmentation or irreversible transformation. This is confirmed by quantitative desorption of the clusters. The reactivity of the supported clusters with CO and H2 was found to be similar to the known reactivities in solution and molecular solid phases. The cluster [(PPh3)Pt(H)(AuPPh3)7](NO3)2 (3) was also immobilized on silica and found to be intact by MAS 31P NMR and desorption experiments. The turnover rate (TOR) for H2−D2 equilibration was determined for these supported clusters at room temperature. The clusters 1 and 2 were good catalysts on silica and alumina supports after treatment at 135 °C under vacuum (TOR = 10−20 s-1), but showed significant activation by treatment at 110 °C under H2 (TOR = 85−220 s-1). Cluster 3/SiO2 gave a similar rate (TOR = 170 s-1) with no thermal activation. All samples subjected to the thermolysis conditions given above were found to be intact by 31P MAS NMR and could be quantitatively desorbed. The high activities of the supported Pt−Au clusters are believed to result from support-promoted, partial PPh3 dissociation. Desorption experiments show that this dissociation is reversible.

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Dihydrogen Activation by Mixed Platinum- and Palladium-Gold Cluster Compounds. Homogeneous Catalytic H2-D2 Equilibration

Cited by 46 publications

References 3 publications

Additivity Effects in the Reactivities of Bimetallic Cluster Ions Pt_mAu_n⁺

Additivity Effects in the Reactivities of Bimetallic Cluster Ions Pt_mAu_n⁺

Synergistic Effects of Gold–Palladium Nanoalloys and Reducible Supports on the Catalytic Reduction of 4-Nitrophenol

Cluster Chemistry on Surfaces: Characterization and Catalytic Studies of Phosphine-Stabilized Platinum−Gold Clusters on Silica and Alumina Supports

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Dihydrogen Activation by Mixed Platinum- and Palladium-Gold Cluster Compounds. Homogeneous Catalytic H2-D2 Equilibration

Cited by 46 publications

References 3 publications

Additivity Effects in the Reactivities of Bimetallic Cluster Ions PtmAun+

Additivity Effects in the Reactivities of Bimetallic Cluster Ions PtmAun+

Synergistic Effects of Gold–Palladium Nanoalloys and Reducible Supports on the Catalytic Reduction of 4-Nitrophenol

Cluster Chemistry on Surfaces: Characterization and Catalytic Studies of Phosphine-Stabilized Platinum−Gold Clusters on Silica and Alumina Supports

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Additivity Effects in the Reactivities of Bimetallic Cluster Ions Pt_mAu_n⁺

Additivity Effects in the Reactivities of Bimetallic Cluster Ions Pt_mAu_n⁺