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چکیده
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Direct ethanol fuel cells (DEFCs) as clean energy-converting devices, have received considerable attention because of their high energy density, less toxicity of ethanol as fuel, and their potential use in variety of applications. However, the major challenges in these fuel cells are high cost and low poison tolerance of Pt, Pd and their alloy materials as excellent electrocatalyst for ethanol oxidation. Significantly, these problems are overcome by decreasing the amount of precious Pt-group metals via increasing its utilization efficiency through the preparation of highly-dispersed supported metal catalysts and by alloying with the non-precious metals like Bi, Pb, Sn, and Cu, which enhances electrocatalytic activity, minimizes the CO poisoning, and also reduces of the amount of noble metal in the anode of DEFCs [1]. In this study, the bismuth-containing metal-organic frameworks (CAU-17) with hexagonal prisms and fiber morphology have been synthesized through a facile ultrasound-assisted wet-chemical approach at room temperature in methanol solutions of Bi(III) nitrate, 1,3,5-benzenetricarboxylic acid (BTC) ligand and CTAB surfactant. Then, Bi-N4 sites on porous carbon (PC) supports were prepared through decomposition of CAU-17 and dicyandiamide (DCD) for preparing Bi-N4/PC electrocatalyst via post thermal treatment at 400 and 800 °C for 1 h at H2/N2 atmosphere [2]. The resulting Bi-N4/PC was used for preparation of Pt-Bi-N4/PC electrocatalyst by redox replacement reaction, which galvanic replacment of Bi atoms with Pt occurs spontaneously. The Pt-Bi-N4/PC electrodes exhbite higher electrocatalytic activity and enhanced poison tolerance for the ethanol oxidation as compared to Pt-Bi/PC, prepared without using of DCD, and commercial Pt/C catalyst. Also, The synthesized electrocatalysts were characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction techniques.
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