کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
65243 48387 2015 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Evaluation of catalytic activity of Ag and Au dendrimer-encapsulated nanoparticles in the reduction of 4-nitrophenol
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Evaluation of catalytic activity of Ag and Au dendrimer-encapsulated nanoparticles in the reduction of 4-nitrophenol
چکیده انگلیسی


• Catalytically active gold and silver nanoparticles were synthesized using poly(amido)amine dendrimers.
• The catalytic activity of the synthesized catalysts was investigated using the 4-nitrophenol reduction by sodium borohydride.
• The kinetics of the catalyzed reduction reaction were evaluated using the Langmuir–Hinshelwood model.

Langmuir–Hinshelwood parameters were determined with the use of gold and silver dendrimer-encapsulated nanoparticles (Au-DENs and Ag-DENs) as catalysts. Dendrimers were used as templating and stabilizing agents to ensure that there is no aggregation of metal nanoparticles. The synthesis of DENs using amine terminated generation 4 poly(amido)amine dendrimer (G4-PAMAM-NH2) was successfully demonstrated. These synthesized DENs were characterized using UV–visible spectrophotometry (UV–vis), electron dispersion X-ray analysis (EDX), and Fourier transformed infrared spectrophotometry (FTIR). High resolution transmission electron microscopy (HRTEM) was used to determine the average particle sizes, and the average particle sizes were found to be 1.23 ± 0.13 and 1.17 ± 0.13 nm for Au- and Ag-DENs, respectively. Comparison of catalytic activity between the two metal nanoparticles was done in terms of thermodynamic parameters obtained from Langmuir–Hinshelwood fits at 298 K. 4-Nitrophenol (NP) reduction by sodium borohydride (NaBH4) in the presence of the synthesized DENs as homogeneous catalysts was used by virtue of being a model reaction. Effect of diffusion barrier in all kinetic runs was addressed by calculations of the second Damköhler number and by the application of the second Fick's law of diffusion. The Langmuir–Hinshelwood model proved to be an efficient model for thermodynamic comparison of the two metal nanoparticles.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Catalysis A: Chemical - Volume 396, January 2015, Pages 1–7
نویسندگان
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