Facile 1D graphene fiber synthesis from an agricultural by-product: A silicon-mediated graphenization route. (February 2019)

• Record Type: Journal Article
• Authors: Fujisawa, Kazunori; Lei, Yu; de Tomas, Carla; Suarez-Martinez, Irene; Zhou, Chanjing; Lin, Yu-Chuan; Subramanian, Shruti; Elías, Ana Laura; Fujishige, Masatsugu; Takeuchi, Kenji; Robinson, Joshua A.; Marks, Nigel Anthony; Endo, Morinobu; Terrones, Mauricio
• Is Part Of: Carbon. Volume 142(2019)
• Page Start: 78
• Page End: 88
• Publication Date: 2019-02
• Subjects: Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2018.10.032
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: A one-dimensional (1D) graphene fiber with a novel structure has been prepared by a heat treatment of rice husk, a natural by-product that contains high amounts of silica. A step-by-step heat treatment of rice husk revealed that (i) carbonization yields porous carbon and silica, (ii) 1D β -SiC nanowires are formed by the carbothermic reduction of silica, (iii) finally 1D graphene fibers are created by silicon sublimation from 1D β -SiC nanowires. Raman spectroscopy and electron microscopy studies revealed that the graphene fiber is composed of a turbostratic multilayer structure. The SiC-derived material exhibits a large crystalline size and turbostratic stacking making each layer as quasi-free-standing graphene, which is confirmed by the 3.9 times higher Raman G′-band intensity over the G-band intensity. Molecular dynamics simulations revealed a high diffusion rate of Si atoms and a volume reduction of the SiC structure at the sublimation temperature. Since the silicon sublimation occurred from multiple points of the SiC nanowire, this led to radially-collapsed fibers and faceted structures with thick-graphitic-layer that are inter-connected (deflated-balloons and inter-connected balloon-like fibers). This facile synthesis route opens up a new avenue to the cost-effective and etching-free production of self-standing graphene for its bulk usage. Graphical abstract: Image 1