Facile synthesis of hierarchical CuO nanostructures with enhanced photocatalytic activity

Herein we present a simple solution-based protocol to produce a highly efficient photocatalyst consisting of a 3D assembly of 2D nanostructures via one-pot synthesis. Such hierarchical assembly allow a very high surface/volume ratio and facing of active photocatalytic surface. Morphological and structural investigations of the as-grown CuO nanostructures have been performed by FESEM, STEM, HRTEM, SAED and XRD analyses. A detailed study of the photocatalytic activity has been carried out, comparing CuO with reference TiO2 nanoparticles: a very high photocatalytic activity has been measured, higher than that of commercial TiO2 and among the best reported in literature for CuO. This can be reasonably ascribed to the synthetic procedure: on the one hand the hierarchical assembly exhibit a very high surface to volume ratio; on the other, the surfactant-free approach allows the whole surface of the nanostructure to be exposed to the chemical environment and hence maximize the photo-degradation of organic pollutants.