A safer and flexible method for the oxygen functionalization of carbon nanotubes by nitric acid vapors

- The so-called “salt effect” is exploited to improve the vapor phase oxidation method.
- Nitric acid vapors are generated adding 20 wt% of Mg(NO3)2 to HNO3 + H2O solution.
- This allows handling more diluted solutions and varying the HNO3 vapor concentration.
- The CNT functionalization degree increases linearly with the HNO3 vapor concentration.
- Selecting the proper acid vapor concentration allows obtaining the desired oxidation degree.