Mechanism of graphene oxide laser reduction at ambient conditions: Experimental and ReaxFF study

Search for a cheap and efficient route of graphene fabrication is still far from its conclusion, and reduction of graphene oxide (GO) is considered one of the most promising ways to achieve this goal. Here we perform combined experimental and computational analysis of a simple yet efficient and environment-friendly method for reducing GO using nanosecond infrared laser irradiation, which can be performed under ambient conditions and does not require an inert atmosphere or vacuum. We demonstrate that ultrafast heating up to 3800 K leads to a fascinating regime of high quality GO reduction even in the presence of atmospheric air. This surprising effect is achieved as an interplay between two seemingly opposite processes: combustion on the highly-defective areas of GO, such as grain boundaries, and defect annealing in its bulk part. As a result, under particular pulse regimes, after a small loss of mass (primarily from its edges), GO transforms into rGO with a high local order and low Raman I(D)/I(G) ratio.