Large-scale synthesis of porous graphene through nanoscale carbothermal reduction etching

Porous graphene, which features nanoscaled pores on the sheets, has shown great potential in many technologically important industries. However, the conversional approaches for the synthesis of porous graphene including high-energy techniques and template etching/growth methods are generally conducted on substrates with high cost and low throughput. Herein, we demonstrate a general and scalable synthetic method for porous graphene via carbothermal reduction reaction using monodisperse zinc oxide nanoparticles. The results indicate that ZnO nanoparticles were first attached on graphene oxide nanosheets by electrostatic interaction, and then undergone a carbothermal reduction reaction at 800 °C to produce the pores on the sheets. While graphene oxide nanosheets were thermally reduced to graphene, all the by-products (carbon monoxide, carbon dioxide, and zinc) escaped from the final products simultaneously. The characterizations of the obtained porous graphene reveal that the pore size is about 11 nm, larger than that of ZnO nanoparticles (~5 nm), which is ascribed to the aggregation of ZnO nanoparticles (~20 nm) on the graphene oxide sheets. These results show the certain correlation among the sizes of pores, ZnO nanoparticles and ZnO aggregations, which gain insight into the controlling of pore size by choosing suitable etching agent.