Studies on Growth Mechanism of Annealed Graphite Powder and Gas-Sensor Applications

High quality micro sheet rhombohedral graphite crystals were synthesized by Hummer method using compounds of MWCNT, K2S2O8 and P2O5. The growth mechanisms were discussed by finite element simulation. The synthetic sheet rhombohedral graphite crystals showed a higher growth rate in radial direction than that in axial direction. Raman spectrum and Fourier transform infrared spectrum indicated that synthesized sheet rhombohedral Graphite had fewer crystal lattice distortions with no impurities. Finite element simulations indicated that the solvent metal convection field in the radial direction was stronger than that in the axial direction. As prepared graphite powder was annealed at 1350 oC to obtain diamond nanoparticles. The as-prepared products were exposed to formaldehyde gas.