Active sites of nitrogen-doped carbon materials for oxygen reduction reaction clarified using model catalysts
Active sites of nitrogen-doped carbon materials for oxygen reduction reaction clarified using model catalysts
复制标题
DOI：
10.1126/science.aad0832
复制
发表时间：
2016-01-22
期刊：
影响因子：
56.9
通讯作者：
Nakamura, Junji
中科院分区：
文献类型：
--
作者：
Guo, Donghui;Shibuya, Riku;Nakamura, Junji
氮（N）掺杂的碳材料对氧还原反应（ORR）表现出高的电催化活性，这对于若干可再生能源系统是必不可少的。然而，ORR活性中心（或多个活性中心）不清楚，这阻碍了高性能催化剂的进一步开发。在这里，我们的ORR活性位点的特点是使用新设计的石墨（高度定向热解石墨）模型催化剂，具有良好定义的p共轭和良好控制的掺杂N物种。ORR活性位点由吡啶N产生。二氧化碳吸附实验表明，吡啶N也产生刘易斯碱性位点。HOPG模型催化剂中每个吡啶N的比活性与N掺杂的石墨烯粉末催化剂的比活性相当。因此，在N掺杂的碳材料中的ORR活性位点是具有刘易斯碱性的碳原子，其紧邻吡啶N。
Nitrogen (N)-doped carbon materials exhibit high electrocatalytic activity for the oxygen reduction reaction (ORR), which is essential for several renewable energy systems. However, the ORR active site (or sites) is unclear, which retards further developments of high-performance catalysts. Here, we characterized the ORR active site by using newly designed graphite (highly oriented pyrolitic graphite) model catalysts with well-defined p conjugation and well-controlled doping of N species. The ORR active site is created by pyridinic N. Carbon dioxide adsorption experiments indicated that pyridinic N also creates Lewis basic sites. The specific activities per pyridinic N in the HOPG model catalysts are comparable with those of N-doped graphene powder catalysts. Thus, the ORR active sites in N-doped carbon materials are carbon atoms with Lewis basicity next to pyridinic N.