Facile Development of Crumpled Graphene Nanoballs for Energy & Environmental Applications

1. Facile Development of Crumpled Graphene Nanoballs for Energy & Environmental Applications Daniel C. Ralph, Cornell University, ECCS 0335765 Evaporation-induced crumpling of two dimensional nanosheets, such as graphene oxide (GO), is an important phenomenon, which is attracting increasing attention. However, a fundamental understanding of the process is still lacking. In this project, the correlations between the confinement force and various parameters, such as evaporation rate, droplet size, and precursor concentration, were investigated systematically. The morphology and size evolution of crumpled GO particles synthesized by a furnace aerosol reactor method were analyzed by both in-line and off-line methods, including scanning mobility particle sizer, aerodynamic particle sizer, dynamic light scattering, and electron microscopy (TEM & SEM). A universal equation of confinement force was derived, from which the evaporation rate and temperature are important factors to be considered. These crumpled nanosheets show high flexibility during applications, enabling the possibility of encapsulation for drug delivery, photocatalysis, solar cells, and electrical energy storage systems. Experimental Setup. (a) Schematic diagram of a furnace aerosol reactor (FuAR) and (b) the possible formation mechanism of crumpled graphene oxide. SMPS indicates the scanning mobility particle sizer, which is an in-line particle size measurement system. Wei-Ning Wang, Yi Jiang and Dr. Pratim Biswas, Washington University in St. Louis Work performed at Washington University in St. Louis Nano Research Facility Morphology evolution of graphene oxide particles as a function of synthesis temperature. (a) to (d) are FE-SEM images and (a’) to (d’) are corresponding TEM images. (a)/(a’) 200°C, (b)/(b’) 400°C, (c)/(c’) 800°C, and (d)/(d’) 1000°C. The inset at each condition is the corresponding photo of graphene oxide collected on a filter.