Preparation of High-Quality Graphene by Sodium Borohydride Reducing Stage-1 FeCl3-GIC via In Situ Hydrogen Exfoliation
High-quality graphene is prepared via In Situ hydrogen exfoliation of the reaction of stage-1 FeCl3-GIC with sodium borohydride solution, followed by washings and sonication. The hydrogen evolved from the borohydride exfoliates the GIC and reduces defect structure in the graphene simultaneously, make it more conjugated. Raman spectrum results show the intensity ratio of the D and G peak is about 0.09, even smaller than that of the original graphite, which is 0.17. The only C1s peak locating at 284.9 eV in another way supports the only one structure in the graphene. SEM image of exfoliated graphene Fig. 2(f) shows that the graphene obtained has curly morphology, which is significantly different from graphite flakes. TEM of the graphene shows a single layer graphene and its overlap with other graphene. Atomic force microscopy (AFM) measure shows that the average thickness of graphene sheets is about 0.530 nm. Proving that the high quality graphene prepared is chiefly single layer. After compression molded into graphene mat, its conductivity reaches 2.85×105S/m, which is about one third of the theoretical value of graphene. This method is promising for mass production of high-quality graphene.
Prof. Seungho Hong
X. Qiao et al., "Preparation of High-Quality Graphene by Sodium Borohydride Reducing Stage-1 FeCl3-GIC via In Situ Hydrogen Exfoliation", Key Engineering Materials, Vol. 744, pp. 458-462, 2017