Abstract: The oxygen reduction reaction (ORR) is a significant cathodic reaction for renewable source applications such as fuel cells and metal-air batteries. However, the slow kinetics of ORR has become the major impediment for the commercial applications. Therefore, catalysts for the ORR are needed to lower the electrochemical over-potential. Although platinum supported on carbon (Pt/C) catalyst is now developed as the commercial catalyst, its low durability and high cost still limit the application. Thus, developing high performance catalysts with superior activity and durability is still an essential task to replace the traditional Pt/C catalyst.

Alloying Pt with a non-precious metal not only decreases the cost but also improves the catalytic performance as a result of synergistic effect between the two elements. Pt-Co system has been paid broad attention because of its relatively high activity and stability.[1] Although the state of the art Pt-Co randomly mixed alloy may exhibit high activity resulted from the so-called ligand effect,[2] its stability remains a troublesome problem owing to the severe agglomeration and dissolution during the ORR process.[3] Recently, Pt-based intermetallic compound has attracted wide interest due to its constant composition and ordered structure, and it has been demonstrated to be a desirable catalyst with excellent stability and anti-poison when compared with the randomly mixed alloy. Nevertheless, a great challenge for the practical application still exists on account of the low activity of pure intermetallic. Thus, synthesizing Pt-based catalysts with concurrently high activity and durability is still a tough problem.

This abstract mainly focuses on a new class of Co doped Pt₃Co intermetallic compound as an efficient catalyst by doping a small number of Co atoms into ordered intermetallic Pt₃Co phase. The obtained catalyst has the special structure with Pt₃Co intermetallic as solvent and Co as solute. The electrochemical tests indicate that the gained catalyst exhibits both higher activity and durability than the commercial Pt/C catalysts, which can be attributed to the unique electronic structure of Co-doped Pt₃Co intermetallic compound. This research may provide a promisingly new idea to synthesize next-generation catalysts for ORR.

References

[1]  D. Wang, H. L. Xin, R. Hovden, H. Wang, Y. Yu, D. A. Muller, F. J. DiSalvo and H. D. Abruña, Nat. Mater., 2013, 12, 81-87.

[2] M. Bele, P. Jovanovič, A. Pavlišič, B. Jozinović, M. Zorko, A. Rečnik, E. Chernyshova, S. Hočevar, N. Hodnik and M. Gaberšček, Chem. Commun., 2014, 50, 13124-13126.

[3]   L. Su, S. Shrestha, Z. Zhang, W. Mustain and Y. Lei, J. Mater. Chem. A, 2013, 1, 12293-12301.