Solvent-Exfoliated and Functionalized Graphene with Assistance of Supercritical Carbon Dioxide

Graphite was successfully exfoliated into graphene by pyrene and another three derivatives (1-pyrenecarboxylic acid (PCA), 1-pyrenebutyric acid (PBA), and 1-pyrenamine (PA)) with the assistance of supercritical carbon dioxide (SC CO2) in this work. The resulting graphene was characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectra, and fluorescence spectra. High-quality and noncovalent functionalized single or few layer graphene were obtained, van der Waals corrected first-principles approach within density functional theory (vdW-DFT2) was used to investigate the interaction energy of different pyrene-derivatives on graphene and inside the two graphene. The results showed that pyrene and pyrene-derivatives can act as a molecular wedge to exfoliate graphene from graphite well. A further graphene/gold nanoparticle composite was also successfully obtained, which indicates that pyrene-derivatives firmly adsorbed on the surface of graphene can act as the interlinkers between graphene and Au NPs or other rare metal nanoparticles. Therefore, the functionalized graphene with different pyrene-derivatives will have potential applications in nanofunctional materials, nanoreactor devices, and catalysis fields.