Synergetic interaction between copper and carbon impurity induces low temperature growth of highly-defective graphene for enhanced electrochemical performance

Abstract

Defect-engineering of few-layer graphene, by modulating local electronic structure and forming highly-active reaction sites, benefits the charge storage and electrochemical reactions. To control defect morphology of graphene, herein, we devise a CH4- chemical vapor deposition (CVD) approach to directly synthesize graphene film with extremely high defect density of 5.9 × 1011 cm−2 and relatively high crystallinity at a low temperature of 700 °C. The C atoms involved in Cu bulk are induced to segregate onto the Cu surface to establish synergetic C–Cu complex catalyst. Theoretical evidence verifies that the interaction between the Cu and C atoms in form of C cluster atop the Cu plane lowers energy barriers for stepwise decomposition of CH4. The 13CH4 isotope data demonstrate that the C clusters are integrated sequentially into the graphene lattice, unraveling the dual roles of carbon impurities. The defective graphene film exhibits a specific capacitance of 10.6 μF/cm2 and excellent electro-catalytic performance. Such a self-induced synergetic catalyst can innovate the methodology of catalysis engineering for controllable synthesis of graphene and other 2D materials.