关键词: 三元纳米合金, 纳米催化剂, 电催化活性, 氧还原反应, 燃料电池

Abstract: Proton exchange membrane fuel cell represents an important electrochemical energy conversion device with many attractive features in terms of efficiency of energy conversion and minimization of environmental pollution. However, the large overpotential for oxygen reduction reaction at the cathode and the low activity, poor durability and high cost of platinum-based catalysts in the fuel cells constitute a focal point of major barriers to the commercialization of fuel cells. The development of nanostructured catalysts shows promises to addresses some of the challenging problems. The ability to engineer the composition and nanostructure of nanoalloy catalysts is important for developing active, robust and low-cost catalysts for fuel cell applications. This article highlights some of the recent insights into the catalytic properties of ternary nanoalloy catalysts prepared by molecularly-engineered synthesis and thermochemically-controlled processing, focusing on oxygen reduction reaction in fuel cells. This approach has demonstrated the abilities to control size, composition, and nanoscale alloying of binary and ternary nanoalloys. A highly-active ternary nanoalloy catalyst consisting of platinum, nickel and cobalt that is supported on carbon (PtNiCo/C) will be discussed as an example, highlighting the importance of nanoscale tuning of structures and composition for the design of fuel cell catalysts. The mass activity of selected PtNiCo/C catalysts has been shown much higher electrocatalytic activity than those observed for their binary counterparts and commercial Pt/C catalysts. Selected examples will also be shown that the catalytic activity can be tuned by the ternary composition. The structural and synergistic properties of the ternary nanoalloy catalysts for the enhancement of the electrocatalytic activity will also be discussed.

Key words: ternary nanoalloys, nanocatalysts, electrocatalytic activity, oxygen reduction reaction, fuel cells