Controllable synthesis of Cu2O hierarchical nanoclusters with high photocatalytic activity

Cu2O nanocrystals with different morphologies and sizes were controllably synthesized by simply adjusting the reaction temperature and duration. The results suggested that Cu2O nanocrystals obtained at 120 degrees C were hierarchical nanoclusters (NCs) with an average size of 25 nm and the NCs were made up of many ultrafine grains with the sizes of 2-7 nm. Such a structure facilitated the generation and transfer of carriers, leading to a high visible-light photocatalytic activity. Further analysis indicated that the Cu2O nanocrystals with smaller size exhibited much better photocatalytic activities in degrading methyl orange (MO) under visible-light irradiation. The best result appeared in the NCs of 25 nm, which could degrade the MO solution (100 ml, 10 mg L-1) completely in 12 minutes with a dosage of 10 mg. That work provides a good method for enhancing the photocatalytic activity of Cu2O and other photocatalysts.