Photothermal Deoxygenation of Graphene Oxide to Graphitic Carbon for Distributed Ignition and Patterning Applications (Preprint)

摘要

In recent years, several researchers have reported on an enhanced photothermal effect exhibited when nanoscale materials such as carbon nanotubes, polyaniline nanofibers or Si nanowires were irradiated using a photographic flash. In these studies, the high surface to volume ratio of the nanomaterials being flashed, coupled with the inability of the small structures to efficiently dissipate the absorbed energy, led to a rapid increase in temperature and subsequent ignition/welding of the materials. Although heating materials through the use of light energy is not a new phenomenon, achieving such a rapid and dramatic temperature change using only millisecond pulses of light demonstrates a tangible and technologically significant capability, unique to nanoscale materials. We have been able to achieve an enhanced photothermally activated reaction by exposing nanostructured graphene oxide (GO) porous networks, to a photographic flash. The exposure results in a pronounced photoacoustic effect along with a rapid temperature increase, which initiates a secondary deoxygenation reaction to yield graphitic carbon and CO2. A photo-initiated reaction could be used to achieve multiple ignition nucleation sites simultaneously. This type of 'distributed ignition' has applications in liquid fuel rocket engines and in high efficiency homogenous charge compression ignition (HCCI) engines, where ignition control is of paramount importance.