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Enhanced Oxygen Reduction Activity by Selective Anion Adsorption on Non-Precious-Metal Catalysts
ACS Catalysis ( IF 11.3 ) Pub Date : 2018-06-20 00:00:00 , DOI: 10.1021/acscatal.8b01584
Kaspar Holst-Olesen 1 , Mateusz Reda 2 , Heine A. Hansen 2 , Tejs Vegge 2 , Matthias Arenz 3
Affiliation  

Non-precious-metal catalysts (NPMC) are promising alternatives to platinum-based catalysts for the oxygen reduction reaction (ORR), which is the cathode reaction in fuel cells. In this paper, we focus on an iron–nitrogen–carbon (Fe/N/C) catalyst, in comparison to platinum, and investigate how these different types of catalysts behave toward selective anion poisoning. The catalysts are studied with respect to their ORR activity, using the rotating disk electrode (RDE) technique in aqueous HClO4, H2SO4, H3PO4, and HCl electrolytes, and the results are supported by density functional theory (DFT) calculations. We find that the ORR on the Fe/N/C catalyst is less affected by anion poisoning than platinum. Surprisingly, it is seen that phosphoric acid not only does not poison the Fe/N/C catalyst, but instead promotes the ORR; this finding is in sharp contrast to the poisoning effect observed on platinum. This is a highly important finding, as modern high-temperature proton exchange fuel cells (HT-PEMFCs) employ membranes consisting of phosphoric acid that is immobilized into a polybenzimidazole (PBI) matrix.

中文翻译:

非贵金属催化剂上选择性阴离子吸附增强的氧还原活性

非贵金属催化剂(NPMC)是用于氧还原反应(ORR)的铂基催化剂的有前途的替代品,该反应是燃料电池中的阴极反应。在本文中,与铂相比,我们将重点放在铁-氮-碳(Fe / N / C)催化剂上,并研究这些不同类型的催化剂对选择性阴离子中毒的行为。使用转盘电极(RDE)技术在HClO 4,H 2 SO 4,H 3 PO 4水溶液中对催化剂的ORR活性进行了研究。和HCl电解质,其结果得到密度泛函理论(DFT)计算的支持。我们发现,与铂相比,Fe / N / C催化剂上的ORR受阴离子中毒的影响较小。令人惊讶地,发现磷酸不仅不会使Fe / N / C催化剂中毒,反而会促进ORR。这一发现与在铂上观察到的中毒作用形成鲜明对比。这是一个非常重要的发现,因为现代高温质子交换燃料电池(HT-PEMFC)使用由磷酸组成的膜,该膜固定在聚苯并咪唑(PBI)基质中。
更新日期:2018-06-20
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