Structurally Ordered Pt3Cr as Oxygen Reduction Electrocatalyst: Ordering Control and Origin of Enhanced Stability

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• 作者：Zhiming Cui ; Hao Chen ; Weidong Zhou ; Mengtian Zhao ; Francis J. DiSalvo
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：November 10, 2015
• 年：2015
• 卷：27
• 期：21
• 页码：7538-7545
• 全文大小：527K
• ISSN：1520-5002

文摘

Ordered intermetallic phases provide predictable control over structure and electronic effects, not afforded by the widely studied alloys. However, because of the lack of a unifying principle or model for controlling the ordering and particle size, it is still a great challenge to synthesize the desired ordered phase (5 nm and smaller). Here, we employ Pt₃Cr as a typical ordered intermetallic phase to comprehensively study the factors that control both the ordering and particle size. Ordered Pt₃Cr intermetallic nanoparticles (鈭? nm) are successfully synthesized using a KCl-matrix method in combination with adjusting annealing conditions. Such structurally ordered Pt₃Cr/C exhibits superior kinetics toward the oxygen reduction reaction (ORR), relative to disordered PtCr alloy phases and commercial Pt/C. More importantly, the ordered Pt₃Cr intermetallic catalyst shows a minimal loss of activity after 5000 potential cycles (14.7%) and a minimal Cr leaching loss after 4 weeks of testing (13.5%). The mechanism for the enhanced stability of ordered phases is discussed and elucidated. The high stability and activity of ordered Pt₃Cr/C make it very promising for application as cathode catalysts for fuel cells. This work provides a guide to optimizing the synthesis of ordered intermetallic catalysts and improving their catalytic performance.