The size and dispersion effect of modified graphene oxide sheets on the photocatalytic H2 generation activity of TiO2 nanorods

Nano graphene oxide (NGO) was produced by further refluxing graphene oxide (GO) sheets in HNO3, and carboxylic acid functionalized graphene oxide (GO–COOH) was obtained by a simple etherification reaction between GO and chloroacetic acid. The GO, GO–COOH and NGO sheets are combined with TiO2 nanorods by a two-phase assembling method, and confirmed by transmission electronic microscopy. The GO–TiO2, GO–COOH–TiO2 and NGO–TiO2 composites are used in a comparative study of photocatalytic H2 generation activity under UV light irradiation. The H2 generation rate of TiO2 nanorods was slightly increased from 15 to 30 mL h−1 g−1 by replacing oleic acid ligands with hydrophilic dopamine, and significantly increased to 105 mL h−1 g−1 after combining with GO sheets. The further comparative study shows that GO–COOH–TiO2 composite has higher H2 generation rate of 180 mL h−1 g−1 than that of GO–TiO2 and NGO–TiO2 composites