Electrospun Poly(vinylidene fluoride)-based Carbon Nanofibers for Hydrogen Storage

摘要

Poly(vinylidene fluoride) (PVdF) fine fiber of 200-300 nm in diameter was prepared through the electrospinning process. Dehydrofluorination of PVdF-based fibers for making infusible fiber was carried out using DBU, and the infusible PVdF-based nanofibers were then carbonized at 900-1800℃. The structural properties and morphologies of the resulting carbon nanofibers were investigated using XRD, Raman IR, SEM, TEM, and surface area & pore analysis. The PVdF-based carbon nanofibers had rough surfaces composed of 20-to 30-nm granular carbons, indicating their high surface area in the range of 400-970 m~2/g. They showed amorphous structures. In the case of the highly ehydrofluorinated PVdF fiber, the resulting carbon fiber had a smoother surface, with d_(002) = 0.34-0.36 nm, and a very low surface area of 16-33 m~2/g. The hydrogen storage capacities of the above carbon nano-fibers were measured, using the gravimetric method, by magnetic suspension balance (MSB), at room temperature and at 100 bars. The storage data were obtained after the buoyancy correction. The PVdF-based microporous carbon nanofibers showed a hydrogen storage capacity of 0.04-0.4 wt%. The hydrogen storage capacity depended on the dehydrofluorination of the PVdF nanofiber precursor, and on the carbonization temperatures.