Abstract

Self-assembled CuO hierarchical nanostructures were synthesized via the hydrothermal reaction of Cu9S5 microcrystals with NH3 in presence of O2 at high-pressure (3.5 MPa). It is shown that small molecules such as NH3 may serve as templates for the development of different sphere-like hierarchical nanostructures, such as self-assembled nanosheets (at 3 h of reaction) and self-assembled nanofibers (at 12 h of reaction). Confinement effects in the hierarchical nanofibers were confirmed by Raman and UV–vis spectroscopy. Additionally, we show that the hierarchical nanofibers exhibited higher solar photocatalytic activity for the degradation of methylene blue.