期刊
ELECTROCHIMICA ACTA
卷 48, 期 3, 页码 263-270出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/S0013-4686(02)00644-8
关键词
dispersed catalysts; oxygen reduction; platinum-vanadium alloy; gas diffusion electrode; polymer electrolyte fuel cell
The electrocatalysis of the oxygen reduction reaction (ORR) on carbon supported Pt:V 1:1 catalyst in polymer electrolyte fuel cells (PEFC) was investigated. At an oxygen pressure of 1 atm results indicate a lower electrocatalytic activity for the ORR in the presence of vanadium. However, at an O-2 pressure greater than or equal to 2 atm an enhanced electrocatalytic property of PtV/C compared with Pt/C is revealed. This result indicates the occurrence of a different electrocatalytic mechanism for the ORR on Pt/C and PtV/C. An increase of mass transport overpotentials is observed for the PtV/C catalyst, and this was related to the presence of vanadium oxide. Indeed, XRD analysis revealed that only about 30% of V present in the catalyst is alloyed with Pt, forming a face centred cubic (fcc) Pt3V solid solution. A thermal treatment at 850 degreesC under reducing atmosphere leads to the formation of an ordered fcc Pt2V phase. After this, the ORR activity of PtV/C at O-2 pressure 1 atm is higher than that of Pt/C. (C) 2002 Elsevier Science Ltd. All rights reserved.
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