Fig. 1

Characterisation of graphene oxide flakes. a Transmission electron microscopy image of graphene oxide. Scale bar: 500 nm. b Fourier transform infrared spectrum of graphene oxide in the middle region (4000–500 cm−1)
Characterisation of graphene oxide flakes. a Transmission electron microscopy image of graphene oxide. Scale bar: 500 nm. b Fourier transform infrared spectrum of graphene oxide in the middle region (4000–500 cm−1)