Studies on the effect of bio-ionic liquid structures on the spontaneous reduction and dispersion stability of graphene oxide in aqueous media

Abstract

Treatment of graphene oxide (GO) at elevated temperature with four choline based bio-ionic liquids (Bio-ILs) having counter anions with different nucleophilicity, namely, choline bicarbonate (chol-HCO₃), choline hydroxide (chol-OH), choline formate (chol-HCOO) and choline caproate (chol-C₅H₁₁COO) resulted in the formation of partially reduced GO (prGO). The prGO formed in the presence of chol-HCOO and chol-C₅H₁₁COO had long term dispersion stability in water (>1 year). The results showed that ILs having strong nucleophiles were able to reduce GO to a higher extent with short term dispersion stability of the prGO, while the ILs with weaker nucleophiles gave the formation of prGO with long term dispersion stability in water.