Abstract：
Here, an approach to produce a hierarchical porous Fe-N-C@TABOH catalyst with densely accessible high intrinsic active FeNx sites is proposed. The method involves a single-step pyrolysis of Zn/Fe-zeolitic imidazolate framework (Zn/Fe-ZIF-H) with tetrabutylammonium hydroxide (TABOH) micelles, which is obtained by utilizing TABOH as a structural template and electronic mediator at room temperature for a brief duration of 16 min. Notably, the yield of Zn/Fe-ZIF-H is 3.5 times that of Zn/Fe-ZIF-N prepared by conventional method. Results indicate that in addition to expediting synthesis and increasing yield of the Zn/Fe-ZIF-H, the TABOH induces a hierarchical porous structure and fosters the formation of more and higher intrinsic active FeNx moieties in Fex-N-C@TABOH, showing that TABOH is a multifunctional template. Crucially, the increased mesoporosity/external surface area and optimized microenvironment of Fe-N-C@TABOH significantly enhance ORR activity by facilitating the formation of high intrinsic active FeNx sites, increasing accessible FeNx sites, and reducing mass transfer resistance. Through structure tailoring and microenvironment optimization, the resulting Fe-N-C@TABOH exhibits superior ORR performance. DFT calculation further validates that the synergistic effect of these two factors leads to low ORR barrier and optimized *OH adsorption energy. This study underscores the importance of structure and electronic engineering in the development of highly active ORR catalysts.
摘要：
这里,提出了一种生产具有密集可及的高本征活性FeNx位点的分层多孔Fe-N-C@TABOH催化剂的方法。该方法涉及用四丁基氢氧化铵（TABOH）胶束对Zn/Fe-沸石咪唑酯骨架（Zn/Fe-ZIF-H）进行一步热解，这是通过在室温下将TABOH用作结构模板和电子介体16分钟的短时间内获得的。值得注意的是,Zn/Fe-ZIF-H的产率是常规方法制备Zn/Fe-ZIF-N的3.5倍。结果表明，除了加快Zn/Fe-ZIF-H的合成和提高产率外，TABOH诱导分层多孔结构，并促进在Fex-N-C@TABOH中形成更多和更高的固有活性FeNx部分，表明TABOH是一个多功能模板。至关重要的是，Fe-N-C@TABOH增加的介孔/外表面积和优化的微环境通过促进高本征活性FeNx位点的形成显着增强ORR活性，不断增加可访问的FeNx站点，并降低传质阻力。通过结构裁剪和微环境优化，所得Fe-N-C@TABOH表现出优异的ORR性能。DFT计算进一步验证了这两个因素的协同作用导致低ORR势垒和优化的*OH吸附能。这项研究强调了结构和电子工程在开发高活性ORR催化剂中的重要性。
