Fig. 4. Dynamic TEM observations of carbon deposition. (a and b) In situ TEM images visualizing the growth of fibrous carbon deposits (carbon nanotubes: CNT) over the Ni/Al₂O₃ catalyst in the LT-DRM atmosphere. Snapshots of the CNT growth. Shooting interval: ∼2 seconds. (c) TEM image of the Ni/Al₂O₃ catalyst taken after subjection to LT-DRM for 6 h. (d) A model for the inhibited CNT growth over the Ni#Y₂O₃ catalyst due to the topological immobilization of the Ni catalysis centre.