Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Materials Laboratory (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123, China.
Sci Rep. 2014 Jan 8;4:3606. doi: 10.1038/srep03606.
The identification of effective components on the atomic scale in carbon nanomaterials which improve the performance in various applications remains outstanding challenges. Here the catalyst residues in individual carbon nanotube (CNT) and carbon nanofiber (CNF) were clearly imaged with a concurrent characterization of their electronic structure by nanoscale scanning transmission X-ray microscopy. Except for prominent catalyst nanoparticle at the tip, tiny catalyst clusters along the tube (fiber) were detected, indicating a migration of the catalysts with the growth of CNTs (CNFs). The observation provides the direct evidence on the atomic metal in CNT for oxygen reduction reported in the literature. Interaction between catalysts (Fe, Ni) and CNTs (CNFs) at the tip was also identified by comparing the X-ray absorption spectra. A deep understanding of catalyst residues such as Fe or Ni in carbon nanomaterials is very vital to growth mechanism development and practical applications.
在原子尺度上识别对提高各种应用性能有积极作用的碳纳米材料的有效成分仍然是一个突出的挑战。在这里，利用纳米尺度扫描透射 X 射线显微镜对单个碳纳米管 (CNT) 和碳纳米纤维 (CNF) 中的催化剂残留物进行了清晰成像，并对其电子结构进行了同时的表征。除了尖端处明显的催化剂纳米颗粒外，还沿着管（纤维）检测到微小的催化剂团簇，表明随着 CNTs (CNFs) 的生长，催化剂发生了迁移。该观察结果为文献中报道的氧还原反应中 CNT 中原子金属的直接证据。通过比较 X 射线吸收光谱，还确定了催化剂（Fe、Ni）和 CNTs (CNFs) 在尖端的相互作用。深入了解碳纳米材料中的催化剂残留物（如 Fe 或 Ni）对于生长机制的发展和实际应用非常重要。
