A facile and scalable approach to develop electrochemical unzipping of multi-walled carbon nanotubes to graphene nanoribbons†
Unzipping of multi-walled carbon nanotubes (MWCNTs) is a promising strategy for scalable preparation of graphene nanoribbons (GNRs). However, current chemical unzipping methods rely on the reactions of MWCNTs with strong oxidants or alkali metals at elevated temperatures, presenting environmental and safety issues. Although several green approaches have been proposed to unzip MWCNTs, most of them are unscalable or incapable of selective unzipping. In this study, we designed a facile electrochemical approach for the scalable preparation of GNRs. The application of constant current to MWCNTs in concentrated sulfuric acid using our designed electrochemical cell allows the preparation of GNRs via intercalation-driven unzipping. This method can control the O/C ratio from 0.16 to 0.24 as well as the GNR unzipping level from partial to full unzipping. Moreover, our proposed method can be scaled up to a rate of 100 g h−1 m−2. The as-prepared GNRs are demonstrated as a catalyst support for the hydrogen evolution reaction.