Measuring the specific surface area of monolayer graphene oxide in water

Abstract Many applications of graphene oxide concern specific surface area. Monolayer graphene has a high specific surface area of about 2630 m2/g, but the specific surface area of monolayer graphene oxide reported in literature (usually 2–1000 m2/g) is much smaller. To date, the exact measurement of the specific surface area of monolayer graphene oxide still remains a challenge. Here we demonstrate that this specific surface area can be measured in water by a rheology-based method. Graphene oxide was fully exfoliated in water to obtain monolayer graphene oxide/water solutions. Its specific surface area was theoretically calculated to be about 2418 m2/g, and was measured to be approximately 2391 (±1292) m2/g. The measured value is obviously larger than those in literature, and is close to the theoretical value. The advantages and disadvantages of this new method have been discussed.