| Direct ethanol fuel cells with high ethanol-tolerant nonprecious metal cathode catalysts for oxygen reduction reaction |
| کد مقاله : 1008-THFC (R1) |
| نویسندگان |
|
مرتضی کاظمی1، حسین غریبی *2، مریم جعفری3، محمد ژیانی3 1شیمی فیزیک- دانشکده علوم پایه-دانشگاه تربیت مدرس-تهران-ایران 2عضو انجمن 3شیمی فیزیک- دانشکده علوم پایه- دانشگاه تربیت مدرس-تهران-ایران |
| چکیده مقاله |
| Direct ethanol fuel cells (DEFCs), which use ethanol as a fuel, have attracted considerable attention due to their relatively high energy density, the non-toxicity of ethanol. However, since the cross-over of ethanol as a fuel in DEFCs can deteriorate the cell performance due to the oxidation of ethanol (EtOH) at the cathode during oxygen reduction reaction (ORR), non-precious metal (NPM) cathode catalysts for ORR have been studied using carbon-based nanostructures as promising alternatives to Pt-based catalysts. Herein, the N-doped carbon nanostructures (Co-N-C) as cathode catalysts were synthesized using Cobalt(II), 2 MeIm, and Poly-pyrrole as a substrate. Two identical cells are fabricated using the same anodes and Co-N-C and commercial 10 wt.% Pt/C as the ORR electrocatalyst for the cathode. The anion-exchange membrane (A201 Tokuyama), with a thickness of 28 µm is used as an electrolyte. 2 M of ethanol in a 2 M KOH solution which was stabled in a 12 ml tank was fed to the anode side and cathode was performed under air-breathing and O2 bleeding modes. In this study, the performance of these two DEFCs was compared to each other. The cell performances with the cathode of Co-N-C and Pt/C with air-breathing are 15.59 mW cm-2 and 7.62 mW cm-2 and with O2-breathing are 20.98 mW cm-2 and 14.91 mW cm-2 respectively (fig. a). the better performance with the O2-breathing state is that the concentration of oxygen is more than the air-breathing state. As it’s mentioned, the difference between the cells is these cathodes, so Co-N-C has better ORR activity than Pt/C (fig. b). The excellent ORR activity of Co-N-C for the DEFC can be attributed to ethanol tolerance in the ORR and low ethanol adsorption energy of the active sites for the ORR of Co-N-C and it’s clearly shown in fig. d that Co-N-C didn't have any responses to ethanol implying the maintained ORR activity in the presence of EtOH. but Pt/C exhibited the sudden current drop in the direction of the oxidation of EtOH with the insertion of EtOH. The Nyquist plot indicates that Co-N-C has small arcs in both air/O2-breathing which is confirmed to low charge transfer (fig. c). |
| کلیدواژه ها |
| DEFC, Ethanol tolerance, Non-precious metal catalyst, Oxygen reduction reaction |
| وضعیت: چکیده برای ارائه پذیرفته شده است |