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عنوان
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Pd/[C2NH2mim][Br] Thin Film Versus Pd/[C8mim][Cl] or Pd/[C8mim]
[BF4]: Catalytic Applications in Electrooxidation of Methanol,
p‑Nitrophenol Reduction and C–C Coupling Reaction
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نوع پژوهش
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مقاله چاپشده در مجلات علمی
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کلیدواژهها
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s Palladium nanoparticle · Ionic liquid · Ultrasonic assisted C–C coupling · Suzuki–Miyaura reaction · Methanol oxidation
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چکیده
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In this study, diferent ionic liquids including 1-aminoethyl-3-methyl-imidazolium bromide [C2NH2mim][Br] (1), 1-methyl3-octylimidazolium chloride [C8mim][Cl] (2) and 1-methyl-3-octylimidazolium tetrafuoroborate [C8mim][BF4] (3) were applied to stabilize Pd nanoparticles (NPs) at toluene/water interface as thin flms. Field emission-scanning electron microscopy (FE-SEM) images showed puckered chains of ionic liquid (1) around the Pd NPs as fower nanostructures. Transmission electron microscopy (TEM) image of Pd/1 showed clearly core–shell nanostructures. Furthermore, applications of Pd/1, Pd/2 and Pd/3 were investigated in the Suzuki–Miyaura C–C coupling reaction in the presence and absence of ultrasonic waves, hydrogenation catalysis of p-nitrophenol reduction and methanol oxidation reaction. Interestingly, Jf (forwarding current density due to methanol oxidation) was observed only for Pd/1. We believe that interactions of –NH2 and imidazolium groups of ionic liquid 1 with Pd particles are very important in producing of puckered shells around the Pd NPs. Injection of electron density from –NH2 group and Br− of ionic liquid 1 to Pd content tends to Pd be softer than other ionic liquids (2 or 3). This efect weakens the strength of Pd–O and facilitates the intermolecular reductive elimination between Pd–O and Pd–C≡O in rate-determining step of methanol oxidation to produce CO2 product. However, electron releasing group accelerates the increasement in negative charge density of metal accelerates intramolecular or intermolecular reduction elimination.
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پژوهشگران
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مهتاب قیطاسی (نفر اول)، سید جعفر حسینی (نفر دوم)، مهرانگیز بهرامی (نفر سوم)، محمود روشنی (نفر چهارم)، مسعود نبوی زاده (نفر پنجم)
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