Customized casting of unstacked graphene with high surface area (>1300 m² g^-1) and its application in oxygen reduction reaction

Introducing graphene protuberances covalently bonded with the graphene sheets is a straightforward strategy to avoid the stacking of graphene layers. The as-obtained unstacked double-layer templated graphene (DTG) is expected to fully demonstrate intrinsic properties of graphene assemblies if its detailed structure and component can be well controlled. Herein, both the lateral size and graphene protuberance size and areal density of DTG were well modulated through adjusting the template morphology and casting procedures. The lateral size of the as-obtained DTG was ranging from 0.4 to 2 μm. They exhibited a very high specific surface area ranging from 1336 to 1579 m² g^-1 and tailorable graphene protuberances with areal density from 5.3 × 10¹⁴ to 7.8 × 10¹⁴ m^-2. DTG flakes with more hydrophilic surface and well tunable reactivity were obtained by introducing nitrogen into DTG through in-situ deposition. The as-synthesized N-doped DTG afforded significantly improved reactivity on oxygen reduction reaction (nearly 50 mV positively shifted onset potential compared with that of pristine DTG and a current preservation of 92.8% after 16,000 s test).