Graphene aerogel modified TiO2 photocatalysts with high performances by controllable agglomeration behaviour of TiO2 nanoparticles

The agglomeration behaviour of various semi-conductor nanoparticles (TiO2, ZnO, etc.) is ubiquitous, which severely degrades the corresponding photocatalytic performances of intrinsic semiconductors and their composites. Graphene aerogel is prepared as a scaffold to combine with TiO2 in this study, and the agglomeration degree of TiO2 nanoparticles is controllable by adjusting the reaction conditions during the hydrothermal process. The lifetime of photoinduced electrons prolonged to 44% for the optimized sample compared to that of the pure TiO2, and the density of the active hydroxyl radical (the major activity material to degrade pollutant molecules) also enhanced significantly. Moreover, the BET area and adsorption ability were enhanced after the optimized reaction process. The degradation rates of rhodamine-B and phenol were as high as 1.84 x 10(-1) min(-1), 1.54 x 10(-2) min(-1) (UV-light irradiation) and 1.08 x 10(-1) min(-1), 1.06 x 10(-2) min(-1) (visible-light irradiation) using the optimized sample.