The production of SiC nanowalls sheathed with a few layers of strained graphene and their use in heterogeneous catalysis and sensing applications

An on-chip growth technique aiming at large-scale production of few-layer epitaxial graphene nanowall (EGNW) arrays by microwave plasma enhanced chemical vapor deposition has been demonstrated. This hetero-architecture is formed by growing edge-oriented SiC nanowalls on Si substrates, followed by surface graphitization, consequently, thus resulting in a heterojunction composed of a 2H-SiC nanowall sheathed by few-layer strained graphene. Similar to epitaxial graphene grown on SiC in an ultrahigh vacuum ambient, structural compressive strain was found in the EGNW and can be relaxed as the layer number of graphene layers increases. More significantly, the SiC-supported strained graphene nanowalls show a remarkably improved catalytic activity ∼425 A/g and low onset potential ∼0.23 V (vs. Ag/AgCl) for the electro-oxidation of methanol as well as excellent pH sensitivity, thus demonstrating their potential applications in sensors, catalyst supports, and other electrochemical devices.