Defect-Free Single-Layer Graphene by 10 s Microwave Solid Exfoliation and Its Application for Catalytic Water Splitting

Mass production of defect-free single-layer graphene flakes (SLGFs) by a cost-effective approach is still very challenging. Here, we report such single-layer graphene flakes (SLGFs) (>90%) prepared by a nondestructive, energy-efficient, and easy up-scalable physical approach. These high-quality graphene flakes are attributed to a novel 10 s microwave-modulated solid-state approach, which not only fast exfoliates graphite in air but also self-heals the surface of graphite to remove the impurities. The fabricated high-quality graphene films (similar to 200 nm) exhibit a sheet resistance of similar to 280 Omega/sq without any chemical or physical post-treatment. Furthermore, graphene-incorporated Ni-Fe electrodes represent a remarkable similar to 140 mA/cm(2) current for the catalytic water oxidation reaction compared with the pristine Ni-Fe electrode (similar to 10 mA/cm(2)) and a 120 mV cathodic shift in onset potential under identical experimental conditions, together with a faradic efficiency of >90% for an ideal ratio of H-2 and O-2 production from water. All these excellent performances are attributed to extremely high conductivity of the defect-free graphene flakes.

Automated summary

A cost-effective physical approach is used to produce defect-free single-layer graphene flakes, which exhibit excellent conductivity and performance in catalytic water oxidation reactions. The high-quality graphene films fabricated without any chemical or physical post-treatment show remarkable properties attributed to the extremely high conductivity of the graphene flakes.