The key to popularizing proton exchange fuel cells is developing highly active, stable, and cost-effective catalysts for oxygen reduction reaction. Pd is considered as an alternative to Pt due to its high tolerance to poisoning and electronic similarity with Pt, which is a robust but expensive catalyst. However, its vulnerability to dissolving in acidic media prevents the use of Pd as an oxygen reduction reaction catalyst. In this study, a facile synthesis method was developed to prepare a carbon-encapsulated Pd catalyst using aniline. The oxidative polymerization of aniline with a Pd precursor formed Pd nanoparticles embedded in a rod-shaped polyaniline matrix. The polyaniline matrix was carbonized using heat treatment, which then acted as a source of N-containing carbon layer that protects Pd nanoparticles from dissolution and improves oxygen reduction reaction activity. The stability and oxygen reduction reaction activity of the synthesized Pd catalyst were strongly dependent on the heat treatment temperature. The Pd catalysts heat-treated at 300 °C and 500 °C exhibited improved activity and stability as compared to commercial Pd/C. We envision that this method is suitable for mass production of active and stable oxygen reduction reaction catalysts in proton exchange fuel cells.

中文翻译：

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质子交换膜燃料电池中碳包覆的Pd催化剂的氧还原反应的简便合成

普及质子交换燃料电池的关键是开发用于氧还原反应的高活性，稳定且具有成本效益的催化剂。由于Pd具有很高的中毒耐受性以及与Pt的电子相似性，Pd被认为是Pt的替代物，Pt是一种坚固而昂贵的催化剂。然而，其易溶于酸性介质的缺点阻止了将Pd用作氧还原反应催化剂。在这项研究中，开发了一种简便的合成方法以使用苯胺制备碳包封的Pd催化剂。苯胺与Pd前体的氧化聚合反应形成了嵌在棒状聚苯胺基质中的Pd纳米颗粒。使用热处理将聚苯胺基质碳化，然后作为含氮碳层的来源，保护Pd纳米颗粒免于溶解并提高氧还原反应的活性。合成的Pd催化剂的稳定性和氧还原反应活性强烈地取决于热处理温度。与商用Pd / C相比，在300°C和500°C热处理的Pd催化剂显示出更高的活性和稳定性。我们设想该方法适用于在质子交换燃料电池中大量生产活性和稳定的氧还原反应催化剂。与商用Pd / C相比，在300°C和500°C热处理的Pd催化剂显示出更高的活性和稳定性。我们设想该方法适用于在质子交换燃料电池中大量生产活性和稳定的氧还原反应催化剂。与商用Pd / C相比，在300°C和500°C热处理的Pd催化剂显示出更高的活性和稳定性。我们设想该方法适用于在质子交换燃料电池中大量生产活性和稳定的氧还原反应催化剂。