Abstract

Self-assembled CuO hierarchical nanostructures were synthesized via the hydrothermal reaction of Cu9S5 microcrystals with NH3 in presence of O-2 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. (C) 2021 Elsevier B.V. All rights reserved.