Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1627180 | Journal of Alloys and Compounds | 2006 | 5 Pages |
Carbon onions with diameters ranging from 5 to 50 nm and carbon-coated nickel nanoparticles with diameters ranging from 10 to 60 nm have been synthesized on a large scale over Ni/Al catalyst by chemical vapor deposition. The approximate ratio of Ni-filled to empty onions as observed by TEM is 1:3.5. In order to eliminate the nickel nanoparticle and obtain pure hollow carbon onions, HNO3 acid was used to dissolve the nickel from the carbon-coated nickel nanoparticles. The carbon onion particles thus obtained have hollow cores and are mainly composed of well-crystallized graphite, as characterized by high-resolution TEM and Raman spectroscopy. In addition, we proposed a simple purification mechanism for Ni-filled carbon onions based on TEM observations.