Highly defective, doping-free graphene framework: A rapid one-step formation avenue

Defective carbon material, especially for graphene, has attractive in the energy conversion and storage field due to its fascinating surface structural and electronic properties. The defective graphene has been synthesized either by high temperature calcination of inorganic salt or from the pristine graphene (or graphene oxide) by violent chemical reaction, both of which are destructiveness and harsh tedious preparation process. The existing mild preparation methods can effectively preserve the planar structure of graphene, but at the expense of defect density. Here, we demonstrate a simple and direct one-step high-temperature hydrothermal method to synthesize doping-free, multi-defect graphene (DMG) framework. During the thermal vapor process under high-temperature and high-pressure, graphene layers are etched and exfoliated layer by layer within a short time. Accompanied by rapidly increasing of edge structures, the resulting DMG presents a superior defect density to those graphene materials reported previously, leading to a robust electrocatalytic activity in oxygen reduction reaction as well as achieving a significantly high capacitance in supercapacitor. This work presents a facile effective synthetic route for realizing high defective graphene materials and also confirms the important role of defective graphene in electrochemical domain without any other dopants.