Department of Materials Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7204, USA.
ChemSusChem. 2009 Jul 20;2(7):658-64. doi: 10.1002/cssc.200800215. Epub 2009 Jun 24.
The stability and oxygen reduction activity of two carbon-supported catalyst materials are reported. The catalysts, Se/Ru and Se/(Ru-Mo), were prepared by using a chemical reduction method. The catalyst nanoparticles were evenly dispersed onto globular amorphous carbon supports, and their average size was ca. 2.4 nm. Thermal treatment at 500 °C for 2 h in an inert argon atmosphere resulted in coarsening of the nanoparticles, and also in some decrease of their activity. A gradual reduction of activity was also observed for Se/Ru during potential-cycle experiments. However, the incorporation of small amounts of Mo into the Se/Ru catalysts considerably improved the stability of the catalyst against dissolution. The Mo-containing samples showed excellent oxygen reduction activities even after cycling the potential 1000 times between 0.7 and 0.9 V. Furthermore, they showed excellent fuel-cell behavior. The performance of the Se/Ru catalysts is greatly improved by the addition of small amounts of elemental Mo. Possible mechanisms responsible for the improvement of the activity are discussed.
本文报道了两种碳载催化剂材料的稳定性和氧还原活性。采用化学还原法制备了催化剂 Se/Ru 和 Se/(Ru-Mo)。催化剂纳米粒子均匀分散在球形无定形碳载体上，平均粒径约为 2.4nm。在惰性氩气气氛中于 500°C 热处理 2 小时导致纳米颗粒粗化，并使它们的活性略有下降。在电位循环实验中，Se/Ru 的活性也逐渐下降。然而，在 Se/Ru 催化剂中加入少量的 Mo 可以显著提高催化剂的稳定性，防止其溶解。含 Mo 的样品在 0.7 至 0.9 V 之间循环电位 1000 次后，仍具有优异的氧还原活性。此外，它们还表现出优异的燃料电池性能。添加少量的元素 Mo 可以极大地提高 Se/Ru 催化剂的性能。讨论了提高活性的可能机制。
