Identifying Intermediates of Oxygen Reduction Reaction on Nitrogen-Doped Fullerene by High-Resolution Tip-Enhanced Raman Scattering 利用高空间分辨针尖增强拉曼散射识别氮掺杂富勒烯催化的氧还原反应中间体

The oxygen reduction reaction (ORR) by the nitrogen-doped fullerene (C59N) catalyst demonstrates an excellent activity in hydrogen fuel cells. However, the intermediates and catalytic active sites in pathways have not been directly characterized, hindering the understanding of the enhanced activity mechanism for ORR on C59N. By taking the inhomogeneity of spatially confined plasmon (SCP) into account, we theoretically propose that the high-resolution tip-enhanced Raman scattering (TERS) can effectively identify different intermediate configurations of ORR on C59N. With the modulation of the focused SCP center position, vibrational modes that are directly related to site-specific O2−C59N interactions in ORR can be lighted up and then selected out by TERS spectra. Furthermore, the vibration-resolved TERS images for the selected modes of different intermediate configurations give spatial hot spot around the adsorption site, providing the in-situ details of catalytic active sites of ORR on C59N. These findings serve as good references for future high-resolution TERS experiments on probing catalytic systems at the molecular scale. 氮掺杂富勒烯(C59N)催化剂在氢燃料电池的氧还原反应(ORR)中表现出良好的活性。然而，C59N上发生的ORR反应路径的中间体和催化活性位点尚未被直接表征，阻碍了我们对C59N催化剂在ORR中活性增强机制的理解。通过在模拟计算中考虑空间限制等离子体(SCP)的不均匀分布，我们从理论上提出高空间分辨针尖增强拉曼散射(TERS)可以有效地识别C59N上ORR的不同中间体构型。通过调整聚焦的SCP位置，ORR中与O2−C59N相互作用有关联的振动模式可以被TERS光谱直接选择出来，并且得到增强。此外，选择出来的振动模式对应的TERS图像在吸附位点周围给出了拉曼热点，提供了ORR在C59N上催化活性位点的原位观测细节。这些发现为今后通过高分辨率TERS技术在分子尺度上探索催化系统提供了良好的参考。