Taniguchi Yurika, Shu Yasuhiro, Takada Ryuji, Miyake Koji, Uchida Yoshiaki, Nishiyama Norikazu
Division of Chemical Engineering, Department of Materials Engineering Science Graduate School of Engineering Science, Osaka University 1-3 Machikaneyama Toyonaka Osaka 560-8531 Japan
Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University Suita Osaka 565-0871 Japan.
Nanoscale Adv. 2023 May 12;5(16):4233-4239. doi: 10.1039/d3na00186e. eCollection 2023 Aug 8.
N-doped carbon materials have attracted considerable attention as highly functional materials because nitrogen doping distorts the carbon lattice, changes the charge density, and introduces additional defects. Among various positions of N atoms in N-doped carbon compounds, pyridinic-N, pyrrolic-N, and valley-N, which are doped at edge sites, exhibit specific electrocatalytic activities during the oxygen reduction reaction (ORR). However, it is difficult to selectively introduce these N atoms into a carbon matrix because the synthesis procedure typically includes high-temperature heat treatment. In this study, we applied a zeolite templating method to synthesize edge site-rich N-doped carbon materials. The sample fabricated using a zeolite template possessed high concentrations of pyridinic-N and valley-N atoms, demonstrating a significantly higher ORR catalytic activity than the sample synthesized without a zeolite template. Additional experiments conducted using various zeolites confirmed the positive effect of N-doped carbons on the ORR catalytic performance. This work demonstrated that the zeolite templating method not only increased the specific surface area and the number of active sites but also selectively created edge sites and improved the quality of the active sites.
氮掺杂碳材料作为高功能材料已引起了广泛关注，因为氮掺杂会使碳晶格发生畸变、改变电荷密度并引入额外的缺陷。在氮掺杂碳化合物中氮原子的不同位置中，掺杂在边缘位点的吡啶型氮、吡咯型氮和石墨型氮在氧还原反应（ORR）过程中表现出特定的电催化活性。然而，由于合成过程通常包括高温热处理，因此很难将这些氮原子选择性地引入碳基体中。在本研究中，我们应用沸石模板法合成了富含边缘位点的氮掺杂碳材料。使用沸石模板制备的样品具有高浓度的吡啶型氮和石墨型氮原子，显示出比无沸石模板合成的样品更高的ORR催化活性。使用各种沸石进行的额外实验证实了氮掺杂碳对ORR催化性能的积极影响。这项工作表明，沸石模板法不仅增加了比表面积和活性位点的数量，还选择性地产生了边缘位点并提高了活性位点的质量。
