Identification of active sites for acidic oxygen reduction on carbon catalysts with and without nitrogen doping
Identification of active sites for acidic oxygen reduction on carbon catalysts with and without nitrogen doping
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DOI：
10.1038/s41929-019-0297-4
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发表时间：
2019-08-01
期刊：
影响因子：
37.8
通讯作者：
Yao, Xiangdong
中科院分区：
文献类型：
--
作者：
Jia, Yi;Zhang, Longzhou;Yao, Xiangdong
由于难以控制碳材料中掺杂物或缺陷的类型及其均匀性，确定碳基无金属催化剂的活性位点仍然是一个有争议的问题。在这里，我们报告了一项关于具有特定五边形碳缺陷模式（D-HOPG）的高取向热解石墨催化剂活性位点评估的概念验证研究。结果表明，通过可控氮掺杂可以选择性地产生特定的碳缺陷类型（在本工作中为边缘五边形）。工作函数分析结合宏观和微观电化学性能测量表明，D-HOPG中的五边形缺陷是酸性氧还原反应的主要活性位点，甚至优于氮掺杂高取向热解石墨中的吡啶氮位点。这项工作使我们能够阐明特定碳缺陷与氮掺杂物质的相对重要性，以及它们各自对观察到的整体酸性氧还原反应活性的贡献。
Owing to the difficulty in controlling the dopant or defect types and their homogeneity in carbon materials, it is still a controversial issue to identify the active sites of carbon-based metal-free catalysts. Here we report a proof-of-concept study on the active-site evaluation for a highly oriented pyrolytic graphite catalyst with specific pentagon carbon defective patterns (D-HOPG). It is demonstrated that specific carbon defect types (an edged pentagon in this work) could be selectively created via controllable nitrogen doping. Work-function analyses coupled with macro and micro-electrochemical performance measurements suggest that the pentagon defects in D-HOPG served as major active sites for the acidic oxygen reduction reaction, even much superior to the pyridinic nitrogen sites in nitrogen-doped highly oriented pyrolytic graphite. This work enables us to elucidate the relative importance of the specific carbon defects versus nitrogen-dopant species and their respective contributions to the observed overall acidic oxygen reduction reaction activity.