Guo Chaozhong, Li Yanrong, Li Zhaoxu, Liu Yao, Si Yujun, Luo Zhongli
College of Materials Science and Engineering/Research Institute for New Materials Technology, Chongqing University of Arts and Sciences, Chongqing, 402160, China.
College of Basic Medical Sciences, Chongqing Medical University, Chongqing, 400016, China.
Nanoscale Res Lett. 2020 Jan 28;15(1):21. doi: 10.1186/s11671-020-3254-x.
Designing appropriate methods to effectively enhance nitrogen-doping efficiency and active-site density is essential to boost the oxygen reduction reaction (ORR) activity of non-platinum Fe/N/C-type electrocatalysts. Here, we propose a facile and effective strategy to design a mesopore-structured Fe/N/C catalyst for the ORR with ultrahigh BET surface area and outstanding conductivity via nanochannels of molecular sieve-confined pyrolysis of Fe ions coordinated with 2,4,6-tri(2-pyridyl)-1,3,5-triazine complexes as a novel precursor with the stable coordination effect. Combining the nanochannel-confined effect with the stable coordination effect can synergistically improve the thermal stability and stabilize the nitrogen-enriched active sites, and help to control the loss of active N atoms during pyrolysis process and to further obtain a high active-site density for enhancing the ORR activity. The as-prepared Fe/N/C electrocatalyst has exhibited excellent catalytic activity with an onset potential of ~ 0.841 V (versus RHE) closely approaching the Pt/C catalyst and high long-term stability in alkaline electrolyte. Besides, low-hydrogen peroxide yield (< 6.5%) and high electron transfer number (3.88-3.94) can be found on this catalyst, indicating that it is a valuable substitute for traditional Pt/C catalysts. This work paves a new way to design high-performance Fe/N/C electrocatalysts and deepens the understanding of active site and ORR catalysis mechanism.
设计合适的方法以有效提高氮掺杂效率和活性位点密度对于提升非铂Fe/N/C型电催化剂的氧还原反应（ORR）活性至关重要。在此，我们提出一种简便有效的策略，通过将与2,4,6-三（2-吡啶基）-1,3,5-三嗪配合物配位的铁离子进行分子筛限域热解，以一种具有稳定配位效应的新型前驱体来设计用于ORR的具有超高BET表面积和出色导电性的介孔结构Fe/N/C催化剂。将纳米通道限域效应与稳定配位效应相结合能够协同提高热稳定性并稳定富氮活性位点，有助于控制热解过程中活性N原子的损失，并进一步获得高活性位点密度以增强ORR活性。所制备的Fe/N/C电催化剂表现出优异的催化活性，起始电位约为0.841 V（相对于RHE），与Pt/C催化剂相近，并且在碱性电解质中具有高长期稳定性。此外，该催化剂上过氧化氢产率低（<6.5%）且电子转移数高（3.88 - 3.94），表明它是传统Pt/C催化剂的有价值替代品。这项工作为设计高性能Fe/N/C电催化剂开辟了一条新途径，并加深了对活性位点和ORR催化机理的理解。
