Promising anode candidates for direct ethanol fuel cell: Carbon supported PtSn-based trimetallic catalysts prepared by B?nnemann method

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• 作者：Seden Beyhan^a ; ^b ; ^{beyhanse@itu.edu.tr} ; ^{seden1980@yahoo.com} ; Christophe Coutanceau^b ; Jean-Michel Lé ; ger^b ; Teko W. Napporn^b ; Figen Kad?rgan^a
• 关键词：Ethanol electrooxidation ; Direct ethanol fuel cell ; PtSn-based trimetallic catalyst ; Pt-based bimetallic catalyst ; Catalyst deactivation
• 刊名：International Journal of Hydrogen Energy
• 出版年：2013
• 出版时间：30 May, 2013
• 年：2013
• 卷：38
• 期：16
• 页码：6830-6841
• 全文大小：2020 K

文摘

To find an efficient anode catalyst for ethanol electrooxidation, several trimetallic PtSnM/C (M?=?Ni, Co, Rh, Pd) and their corresponding bimetallic PtX/C (X?=?Sn, Ni, Co, Rh, Pd) catalysts were synthesized by B?nnemann's colloidal precursor method and evaluated by comparing their electrocatalytic activity using conventional electrochemical techniques. For better understanding of the catalyst deactivation during the ethanol electrooxidation, chronoamperometric test was also combined to X-ray photoelectron spectroscopy (XPS) analysis. A significant finding is that trimetallic compositions PtSnCo/C and PtSnNi/C have enhanced activity compared to that of PtSn/C, with lower onset potential for ethanol electrooxidation and notably improved peak current densities. Thus the presence of Ni and Co heteroatom seems to promote C-C bond cleavage and facilitate the removal from the catalyst surface of adsorbed intermediates. These trends are satisfactorily confirmed by testing in a direct ethanol fuel cell (DEFC), since trimetallic PtSnNi/C and PtSnCo/C anode catalysts have significantly higher overall performance and peak power density than Pt/C, PtSn/C or other trimetallic catalyst compositions PtSnRh/C or PtSnPd/C. Furthermore, the presence of Ni or Co helps to improve the weak stability of PtSn/C by providing a stronger Pt-carbon support interaction. XPS results revealed that the surface Pt/Sn atomic ratio of PtSnNi/C catalyst only slightly decreased even after 12?h at 500?mV. On the other hand, a higher concentration of oxide species appeared on the treated PtSn/C surface as a result of a high degradation of carbon support.