Efficient and Superiorly Durable Pt-Lean Electrocatalysts of Pt鈭扺 Alloys for the Oxygen Reduction Reaction

详细信息    查看全文

• 作者：Yu Dai ; Lihui Ou ; Wei Liang ; Fan Yang ; Yuwen Liu ; Shengli Chen
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：February 10, 2011
• 年：2011
• 卷：115
• 期：5
• 页码：2162-2168
• 全文大小：884K
• 年卷期：v.115,no.5(February 10, 2011)
• ISSN：1932-7455

文摘

The commercial viability of polymer electrolyte membrane fuel cells in transportation applications will rely on significant reductions in the amount and great improvements in the stability of Pt in their cathodes to catalyze the oxygen reduction reaction (ORR). We demonstrated through first-principle theoretical calculations and experimental measurements that alloying Pt with 5d transition metal W could help to accomplish this aspiration. It was shown that the strong surface segregation tendency of Pt in Pt鈭扺 alloys and the peculiar electronic effect of W to Pt allow facile formation of stable Pt-enriched surfaces with likely better-than-Pt ORR activity at Pt-lean alloys such as PtW₂, in contrast to the previously reported Pt alloy ORR electrocatalysts which mostly have to be Pt-rich in total composition (e.g., Pt₃M). The prepared PtW₂ alloy catalysts exhibited a Pt mass activity nearly 4 times higher than the pure Pt catalysts and almost no changes in the activity and surface area in over 30,000 cycles of potential cycling under oxidizing conditions of ORR, in contrast to significant losses seen with the pure Pt catalyst. In addition, the present study also showed a density functional theory-based multiple-descriptor strategy for screening durable and efficient bimetallic catalysts of low precious metal contents.