Cobalt nitrogen-doped carbon (Co-NC) catalysts are synthesized for oxygen reduction reaction (ORR) via the pyrolysis of zinc-mediated and SiO-templated 2,6-diaminopyridine (DAP) composites. The resulting Co-NC(Zn12-SiO[20])-900 demonstrates exceptional ORR activities, with half-wave and onset potentials of 0.835 V and 0.875 V, respectively, which is similar to Pt/C catalyst. In long-term durability test, the Co-NC(Zn12-SiO[20])-900 catalyst exhibits a negligible E shift, and in methanol tolerance tests, it displays significantly better performance than commercial Pt/C catalyst. The superior performance can be attributed to the hierarchical porous structure, dense and highly accessible Co-N and graphitic nitrogen (g-N) sites. The high content of Co-N and g-N sites enhances 3d-orbital filling and reduces the Co centers' on-site magnetic moment, as calculated by density functional theory. This may lead to a decrease in the energy barrier of the rate-determining step (RDS), which in turn enhances the intrinsic activity of the ORR.

中文翻译：

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用于氧还原反应的富配位氮和分级多孔结构的Co-NC催化剂

通过热解锌介导和 SiO2 模板的 2,6-二氨基吡啶 (DAP) 复合材料，合成了用于氧还原反应 (ORR) 的钴氮掺杂碳 (Co-NC) 催化剂。所得的Co-NC(Zn12-SiO[20])-900表现出优异的ORR活性，半波和起始电位分别为0.835 V和0.875 V，与Pt/C催化剂相似。在长期耐久性测试中，Co-NC(Zn12-SiO[20])-900催化剂表现出可忽略不计的E位移，并且在甲醇耐受性测试中，其表现出明显优于商业Pt/C催化剂的性能。优异的性能可归因于分级多孔结构、致密且高度可接近的Co-N和石墨氮(gN)位点。根据密度泛函理论计算，Co-N 和 gN 位点的高含量增强了 3d 轨道填充并降低了 Co 中心的现场磁矩。这可能会导致限速步骤 (RDS) 的能垒降低，从而增强 ORR 的内在活性。