Continuous Production of Graphite Nanosheets by Bubbling Chemical Vapor Deposition Using Molten Copper

We report a bubbling chemical vapor deposition method for mass production of high-quality graphite nanosheets using molten copper as the catalyst for continuous growth. Bubbles containing precursor gas (CH4 or natural gas) are produced by inserting an aerator into molten copper. High-quality graphite nanosheets with a thickness ranging from a few to 40 graphitic layers are grown on bubble surfaces and carried to the copper surface. The production rate can be as high as 9.4 g/h using a crucible with a volume of 3 L. The high quality of the graphite nanosheets is demonstrated by composites with very high conductivity. The highly conductive composite shows excellent performance in an electromagnetic interference (EMI) shielding application with an EMI effectiveness of >70 dB at X band. Moreover, except for precursor gases, the lack of other chemicals in the growth process makes it an environmentally friendly approach. Natural gas can also be used as the precursor, making it a low-cost production. In addition, the naturally crumpled feature of the graphite nanosheets should allow them to ber used in multiple applications, because restacking can be prevented.