Robust graphene oxide composite films applicable to solar water evaporators prepared via covalent cross-linking

Abstract

Hydrophilic graphene oxide (GO) films have been extensively studied in the field of water purification for oil–water separation and seawater desalination. However, GO films always exhibit inferior mechanical performance because of their structural defects resulting from oxidation. Covalent cross-linking between nanosheets in GO films makes them less susceptible to relative displacement and structural damage under force. Herein, we synthesized a sulfosuccinic acid (SSA) crosslink adjacent to GO nanosheets via covalent bonding interactions to achieve robust GO-SSA composite films. The optimal tensile strength and toughness of these films were approximately 3 and 4 times higher, respectively, than those of pure GO films. Our robust GO-SSA composite film applied as a solar evaporator presented a high evaporation rate of 2.11 kg m⁻² h⁻¹ under simulated solar light irradiation (1.0 kW m⁻²). Such integration demonstrates the advantage of this new strategy in preparing covalent interaction-reinforced graphene films.