A multi-step exfoliation approach to maintain the lateral size of graphene oxide sheets

It is demonstrated that the yield of graphene oxide sheets (GO) obtained by the sonication of graphite oxide (GrO) can be enhanced without detriment to the size of the sheets by using a simple multi step procedure. The procedure increases the total exfoliation yield by up to 15% (regardless of the GO sheet size) compared to continuous sonication and by up to 45% in the case of GO sheets of maximum lateral size. The effects of sonication on the exfoliated sheets and on their tridimensional structure are suggested.