Temperature Dependence of Oxygen Reduction Activity at Carbon-Supported PtXCo (X = 1, 2, and 3) Alloy Catalysts Prepared by the Nanocapsule Method
Temperature Dependence of Oxygen Reduction Activity at Carbon-Supported PtXCo (X = 1, 2, and 3) Alloy Catalysts Prepared by the Nanocapsule Method
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DOI：
10.1021/jp712025q
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发表时间：
2008-05
影响因子：
3.7
通讯作者：
H. Yano;Jung-Min Song;H. Uchida;Masahiro Watanabe
中科院分区：
文献类型：
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作者：
H. Yano;Jung-Min Song;H. Uchida;Masahiro Watanabe
采用纳米胶囊法制备了单分散的PtXCo（原子比，X = 1，2，3）合金纳米粒子负载于炭黑（CB，金属负载量为50wt%）上。通过扫描透射电子显微镜测量的平均粒径（d）为1.9（X = 3）至2.4nm（X = 1）。合金组成被发现是很好地控制到预计值之间的支持粒子。采用多通道流动双电极（M-CFDE）方法，在30 ~ 100 °C的氧饱和的0.1M HClO 4溶液中，考察了Nafion涂层PtXCo/CB催化剂的氧还原反应（ORR）活性和H2 O2产率。在30 - 80 °C的温度范围内，在X = 3（d = 1.9 nm）下ORR的表观速率常数kapp（每真实的活性表面积）的值最大，与Pt/CB（50重量% Pt，d = 2.6 nm）相比为2.2倍，即，由于具有较高比表面积的优点，Pt的质量活性预期提高3.3倍。Pt 3Co/CB还具有良好的耐腐蚀性能。
Monodispersed PtXCo (atomic ratio, X = 1, 2, and 3) alloy nanoparticles supported on carbon black (CB, 50 wt % metal loading) were prepared by the nanocapsule method. The average particle diameters (d) measured by scanning transmission electron microscopy ranged from 1.9 (X = 3) to 2.4 nm (X = 1). The alloy composition was found to be well-controlled to the projected value among the supported particles. Oxygen reduction reaction (ORR) activity and H2O2 yield at Nafion-coated PtXCo/CB catalysts were examined in O2-saturated 0.1 M HClO4 solution at 30 to 100 °C by using the multichannel flow double electrode (M-CFDE) method. In the temperature range from 30 to 80 °C, the value of apparent rate constant kapp (per real active surface area) for the ORR at X = 3 (d = 1.9 nm) was the largest, by a factor of 2.2 compared with that of Pt/CB (50 wt % Pt, d = 2.6 nm), i.e., the mass activity of Pt was expected to be enhanced by 3.3 times due to an advantage of higher specific surface area. The Pt3Co/CB also exhibite...