Bio-derived three-dimensional hierarchical carbon-graphene-TiO2 as electrode for supercapacitors.

This paper reports a novel loofah-derived hierarchical scaffold to obtain three-dimensional biocarbon-graphene-TiO2 (BC-G-TiO2) composite materials as electrodes for supercapacitors. The loofah scaffold was first loaded with G and TiO2 by immersing, squeezing, and loosening into the mixed solution of graphene oxide and titania, and then carbonized at 900 °C to form the BC-G-TiO2 composite. The synergistic effects of the naturally hierarchical biocarbon structure, graphene, and TiO2 nanoparticles on the electrochemical properties are analyzed. The biocarbon provides a high interconnection and an easy accessibility surface for the electrolyte. Graphene bridged the BC and TiO2 nanoparticles, improved the conductivity of the BC-G-TiO2 composite, and increased the electron transfer efficiency. TiO2 nanoparticles also contributed to the pesudocapacitance and electrochemical stability.