Graphene oxide aerogels constructed using large or small graphene oxide with different electrical, mechanical and adsorbent properties

Abstract

The performances of graphene oxide aerogels (GOA) are studied by constructing them using different lateral sizes of graphene oxide (GO). Gelatinization of GO hydrosol is realized using a cross-linking agent, poly(vinyl alcohol) (PVA), and then solution-freeze-lyophilization is carried out to construct the cross-linking network of GOA. The contact points in GOA constructed using large sized GO (GOA₃₂₅) were fewer than those in the GOA using small sized GO (GOA_10 000). It is the contact points that decide the micro-structure of GOA, and hence the performances. The size effect of the structural units is studied by investigating the electrical conductivity, mechanical strength, and adsorption capacity. The electrical conductivity of GOA₃₂₅ can reach 0.78 S m⁻¹ after carbonization at 800 °C, which was much higher than that of carbonized GOA_10 000 (0.53 S m⁻¹). The compression modulus of GOA₃₂₅ was 0.51 MPa, while the value for GOA_10 000 was 0.04 MPa. The adsorption capacity of GOA₃₂₅ was also higher than that of GOA_10 000 for adsorbing both hydrophilic and oleophilic media.