Kim Yunjin, Min Jiho, Ko Keonwoo, Sravani Bathinapatla, Chougule Sourabh S, Choi Yoonseong, Choi Hyeonwoo, Hong SeoYeong, Jung Namgee
Graduate School of Energy Science and Technology (GEST), Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea.
Nanomaterials (Basel). 2022 Oct 28;12(21):3800. doi: 10.3390/nano12213800.
The development of non-Pt or carbon-based catalysts for anion exchange membrane fuel cells (AEMFCs) requires identification of the active sites of the catalyst. Since not only metals but also carbon materials exhibit oxygen reduction reaction (ORR) activity in alkaline conditions, the contribution of carbon-based materials to ORR performance should also be thoroughly analyzed. However, the conventional CN poisoning experiments, which are mainly used to explain the main active site of M-N-C catalysts, are limited to only qualitative discussions, having the potential to make fundamental errors. Here, we report a modified electrochemical analysis to quantitatively investigate the contribution of the metal and carbon active sites to ORR currents at a fixed potential by sequentially performing chronoamperometry with two reaction inhibitors, CN and benzyl trimethylammonium (BTMA). As a result, we discover how to quantify the individual contributions of two active sites (Pt nanoparticles and carbon support) of carbon-supported Pt (Pt/C) nanoparticles as a model catalyst. This study is expected to provide important clues for the active site analysis of carbon-supported non-Pt catalysts, such as M-N-C catalysts composed of heterogeneous elements.
开发用于阴离子交换膜燃料电池（AEMFC）的非铂或碳基催化剂需要确定催化剂的活性位点。由于不仅金属而且碳材料在碱性条件下都表现出氧还原反应（ORR）活性，因此也应深入分析碳基材料对ORR性能的贡献。然而，传统的CN中毒实验主要用于解释M-N-C催化剂的主要活性位点，仅限于定性讨论，有可能产生根本性错误。在此，我们报告了一种改进的电化学分析方法，通过依次使用两种反应抑制剂CN和苄基三甲基铵（BTMA）进行计时电流法，定量研究金属和碳活性位点在固定电位下对ORR电流的贡献。结果，我们发现了如何将碳载铂（Pt/C）纳米颗粒作为模型催化剂的两个活性位点（Pt纳米颗粒和碳载体）的各自贡献进行量化。该研究有望为碳载非铂催化剂（如由异质元素组成的M-N-C催化剂）的活性位点分析提供重要线索。
