New Insights into the Reactivity of Detonation Nanodiamonds during the First Stages of Graphitization

The present study aims to compare the early stages of graphitization of the same DND source for two annealing atmospheres (primary vacuum, argon at atmospheric pressure) in an identical set-up. DND samples are finely characterized by a combination of complementary techniques (FTIR, Raman, XPS, HR-TEM) to highlight the induced modifications for temperature up to 1100 & DEG;C. The annealing atmosphere has a significant impact on the graphitization kinetics with a higher fraction of sp(2)-C formed under vacuum compared to argon for the same temperature. Whatever the annealing atmosphere, carbon hydrogen bonds are created at the DND surface during annealing according to FTIR. A nano effect , specific to the < 10 nm size of DND, exalts the extreme surface chemistry in XPS analysis. According to HR-TEM images, the graphitization is limited to the first outer shell even for DND annealed at 1100 & DEG;C under vacuum.

Automated summary

This study compared the early stages of graphitization of DND source under two different annealing atmospheres and found that the atmosphere significantly impacts the graphitization kinetics. More sp(2)-C was formed under vacuum compared to argon at the same temperature, with carbon hydrogen bonds formed on the DND surface during annealing regardless of atmosphere. The nano effect of DND's <10 nm size was highlighted in XPS analysis, where HR-TEM images showed that graphitization was limited to the first outer shell even at 1100°C under vacuum.