Selective Oxidation of 1,6‐Hexanediol to 6‐Hydroxycaproic Acid over Reusable Hydrotalcite‐Supported Au–Pd Bimetallic Catalysts

Tuteja, Jaya; Nishimura, Shun; Choudhary, Hemant; Ebitani, Kohki

doi:10.1002/cssc.201500255

Cited by 17 publications

(18 citation statements)

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“…Adding a second metal to a host metal can create favorable catalytic properties (e.g., selectivity, activity, and stability) in forming a bimetallic catalyst. − The combination of palladium (Pd) and gold (Au) is widely known as a bimetallic catalyst, and it has shown promising catalytic properties in the synthesis of vinyl acetate − and hydrogen peroxide. − The catalytic activity of Pd–Au catalysts primarily originates from ensemble effects which are directly related to the local composition of catalytically active Pd and inert Au atoms . The relative compositions of Pd and Au can be controlled in various chemical ways, , and as mentioned above, Pd–Au catalysts have shown enhanced reactivity and selectivity in several oxidative reactions including the oxidation of alcohols, − CO, − and aromatic C–H bonds . Specifically, when the Pd and Au ratio is 4:1, alloyed Pd–Au/SiO 2 nanoparticles not only have better catalytic activity in comparison to other ratios of Pd and Au (16:1 and 8:1) or pure Pd but also become more stable than the pure Au catalysts for long-term usage .…”

Section: Introductionmentioning

confidence: 99%

Surface Alloy Composition Controlled O₂ Activation on Pd–Au Bimetallic Model Catalysts

Han

Mullins

2018

ACS Catal.

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Oxygen is an important reactant in several catalytic conversions and partial oxidation reactions on Pd–Au alloy surfaces; however, adsorption and dissociation are not fully understood, especially as a function of the surface alloy composition. In this study, we probe the influence of the atomic makeup of the surface of Pd–Au catalysts regarding control of the catalytic activity toward O2 dissociation and the reactivity of the resulting oxygen adatoms. To experimentally investigate this, we prepared various bimetallic surfaces under ultrahigh vacuum via evaporation of Pd onto a Au(111) surface. Hydrogen molecules were used to characterize the composition of the Pd–Au surfaces, which we simplistically group into two categories: (i) Pd–Au interface sites and (ii) Pd(111)-like island sites. When the Pd coverage is 1.0 ML, which predominantly indicates Pd–Au interface sites, no dissociative adsorption of O2 at 300 K is observed, but dissociation begins to be measurable on the surfaces with larger Pd loadings (greater than 1.5 ML), which we believe leads to Pd(111)-like islands on the surface. We also find that adsorbed oxygen atoms are very reactive at the Pd–Au interface sites via measurements of the CO oxidation reaction at relatively low temperatures (<200 K); however, CO oxidation can also take place at higher temperatures (∼400 K) and in this case is very dependent on Pd coverage, being strongly related to the number of Pd(111)-like islands, which bind Oa relatively strongly. From our experimental results, we estimate the barrier to dissociation of O2 and also the CO oxidation reaction barrier, which is an indirect measure of the reactivity of the adsorbed atomic oxygen. From our analysis, we find that, upon increasing Pd coverage, the dissociation barrier for O2 steadily decreases and, further, the reaction barrier for CO oxidation continuously increases. Finally, oxygen molecularly adsorbs on the Pd–Au bimetallic surface and is a precursor to dissociative O2 chemisorption, just as with pure Pd surfaces, and additionally, the enhanced reactivity of adsorbed atomic oxygen originates at the interfaces between Pd and Au domains.

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Section: Introductionmentioning

confidence: 99%

Surface Alloy Composition Controlled O₂ Activation on Pd–Au Bimetallic Model Catalysts

Han

Mullins

2018

ACS Catal.

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“…Among them, AA has been well reviewed elsewhere. [28][29][30] Herein, we summarize the progress in the synthesis of four important α,ω-C6 bifunctional compounds, HHA, ACA, HDO and HMD 13,31 (Fig. 1).…”

Section: Qian LImentioning

confidence: 99%

“…39 This high selectivity of the biocatalytic reaction exerted great advantage over metal-catalyzed oxidation of HDO. 31 Further researches including identification, characterization and modification of the responsible enzyme(s) may bring more remarkable results.…”

Section: Cdwmentioning

confidence: 99%

“…Moreover, the Au 40 Pd 60 -DDAO/HT was reusable (at least 5 times without any further treatment) and stable under the reaction conditions. 31 All the superiorities afforded high activity and product yield of the oxidation of HDO to HHA. However, the demand of noble metal catalyst, H 2 O 2 and base made it less friendly from the economic and environmental view.…”

Section: Introductionmentioning

confidence: 99%

“…[36][37][38] These chemical processes often suffer from drawbacks such as alkali-metal catalysts, high pressure, high temperature (>100 °C) or/and long reaction time. Herein, three chemical synthesis routes of HHA from AA, 38 CHONE 16 and HDO, 31 as well as four biological synthesis processes of HHA from HDO, 39 cyclohexanol (CHOL), 22 cyclohexane (CH) 32 and sugar/glycerol 40 are reviewed.…”

Section: Introductionmentioning

confidence: 99%

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Recent advances in the sustainable production of α,ω-C6 bifunctional compounds enabled by chemo-/biocatalysts

Zhang

Zhao

et al. 2022

Green Chem.

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Surfactant‐Assisted Suzuki–Miyaura Coupling Reaction of Unreactive Chlorobenzene over Hydrotalcite‐Supported Palladium Catalyst

et al. 2017

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Ah ydrotalcite-supported palladium chloride (PdCl 2 /HT) catalyst has been developed for the Suzuki-Miyaura coupling (SMC) reaction. As-prepared PdCl 2 /HT effectively catalyzed the SMC reaction of bromobenzene under air to afford > 99 %b iphenyl yields and the catalyst could be reused without any significant loss in catalytic activity.T he moderate activity (69 %b iphenyly ields) of the PdCl 2 /HT catalystf or chlorobenzene was improved, resulting in biphenyl yields of up to 96 %u sing as urfactant as an additive. Among various surfactants employed, Triton X-100 (TX-100) enhanced the catalytic performances of PdCl 2 /HT the most. The X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) of bare and surfactant-treated PdCl 2 /HTc atalysts depicted the ligation of the Pd speciesb yT X-100i nfluenced the electronic structure of the Pd species, leading to efficient catalysis.Amongt he various CÀCb ondf orming reactions, the palladium-catalyzed Suzuki-Miyaurac oupling (SMC) reactioni so ne of the mostw idely explored organicr eaction owing to its synthetic versatility. [1] Since the first syntheticp rotocol in 1979, [2] the SMC reaction has been explored extensivelyt oe nhance catalytic efficiency using various catalyst/ligand systems. [1, 3] However,m ost of the highly active catalytic systems use homogeneous palladium speciesw ith air-sensitive,e xpensive and environmentallyu nfriendly phosphine ligands. Consequently, heterogeneous catalysts were designed to support activeP d specieso nd ifferent materials such as silica, [4] carbon, [5] zeolites, [6] metal-organic frameworks, [7] and so on. [8] Although these catalysts wereo ptimized to effectively convert aryl iodides or bromides, they exhibited limited scope forl ess reactive but economical and readily availablea ryl chlorides. Therefore, the development of highly active heterogeneous catalyst that can facilitate coupling of aryl chlorides is of high interest to researchers.

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Selective Oxidation of 1,6‐Hexanediol to 6‐Hydroxycaproic Acid over Reusable Hydrotalcite‐Supported Au–Pd Bimetallic Catalysts

Cited by 17 publications

References 56 publications

Surface Alloy Composition Controlled O₂ Activation on Pd–Au Bimetallic Model Catalysts

Surface Alloy Composition Controlled O₂ Activation on Pd–Au Bimetallic Model Catalysts

Recent advances in the sustainable production of α,ω-C6 bifunctional compounds enabled by chemo-/biocatalysts

Surfactant‐Assisted Suzuki–Miyaura Coupling Reaction of Unreactive Chlorobenzene over Hydrotalcite‐Supported Palladium Catalyst

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Selective Oxidation of 1,6‐Hexanediol to 6‐Hydroxycaproic Acid over Reusable Hydrotalcite‐Supported Au–Pd Bimetallic Catalysts

Cited by 17 publications

References 56 publications

Surface Alloy Composition Controlled O2 Activation on Pd–Au Bimetallic Model Catalysts

Surface Alloy Composition Controlled O2 Activation on Pd–Au Bimetallic Model Catalysts

Recent advances in the sustainable production of α,ω-C6 bifunctional compounds enabled by chemo-/biocatalysts

Surfactant‐Assisted Suzuki–Miyaura Coupling Reaction of Unreactive Chlorobenzene over Hydrotalcite‐Supported Palladium Catalyst

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Surface Alloy Composition Controlled O₂ Activation on Pd–Au Bimetallic Model Catalysts

Surface Alloy Composition Controlled O₂ Activation on Pd–Au Bimetallic Model Catalysts