Anomalous thermal stability in supergiant onion-like carbon fullerenes. (November 2018)

• Record Type: Journal Article
• Authors: Zhao, Heng; Shi, Qiao; Han, Zhengde; Gong, Hao; Zhang, Zhisen; Wu, Shunqing; Wu, Jianyang
• Is Part Of: Carbon. Volume 138(2018)
• Page Start: 243
• Page End: 256
• Publication Date: 2018-11
• Subjects: Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2018.06.012
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Onion-like carbon fullerenes (OLCFs) are a promising material for applications in nanoscale devices, medicine, lubrication and superhard materials. Knowledge of the pyrolysis chemistry of OLCFs helps understanding the thermal-induced erosion of carbon-based resources and spacecraft materials. Here, using first-principle-based ReaxFF atomistic simulations, thermal and dynamical characteristics of supergiant 20-shell OLCF having concentric arrangement of C60 @C240 @ … @C24000 are explored. Fullerenes@20-shell OLCF yield larger average radii than isolated single-walled fullerenes (SWFs) at the same scale. The intershell-spacing@OLCF exhibits a reduction tendency from inner to outer shells, but is higher than that of bulk graphite. Because of nonbonded intershell forces, fullerenes@20-shell OLCF are energetically favorable over the corresponding isolated SWFs. In contrast to nonmonotonic variation of melting point with size and shell-index in SWFs and other nanoparticles, an anomalous shell-dependent melting instability in the 20-shell OLCF is identified due to the combined effects of geometrical size, nanoconfinement and surface; Both inner and outer fullerenes are not so resistive against heating, nor are they as strong as the identical-size isolated SWFs, however, the intermediate shells, locally similar to curved graphite, demonstrate higher heat-resisting property than identical-size isolated SWFs. Topological analysis reveals morphological transformation of four stages involving Stone-Wales rearrangement, heterogeneous defects nucleation, amorphization and fragmentation. Graphical abstract: Supergiant onion-like carbon fullerene exhibits an anomalous shell-index dependent melting instability as a consequence of the combined effects of size, confinement and surface. Image 1