Controllable growth and photocatalytic activity of Cu₂O solid microspheres

Graphical abstract: - Highlights: • 3 μm uniform Cu₂O solid microspheres with abundant nanopores are achieved. • NH₂OH·HCl and SDS are main factors that manipulate morphologies of Cu₂O particles. • Surface features of microspheres influenced the photocatalytic activity of Cu₂O. • Microspheres are transforming to polyhedrons with extended holding time. - Abstract: A series of Cu₂O solid microspheres with different surface features were prepared and their photocatalytic activities were studied. The experiment conditions were investigated and the formation mechanism was explored systematically. It was found that varying the amounts of NH₂OH·HCl reductant in alkaline solutions changed the reaction process and thus altered the surface features of Cu₂O microspheres. Sodium dodecyl sulfate (SDS) surfactant, introduced as a morphology directing agent, caused the nuclei aggregation and growth process of Cu₂O solid microspheres by precisely realizing the opposite charges’ directional attraction. This SDS-mediated method can be readily extended to synthesizing solid microspheres of other metal oxides. Meanwhile, it was found that Cu₂O solid microspheres with abundant nanopores on the surface showed much higher efficient catalytic activity for decoloring methyl orange (MO) aqueous solution than with other surface features under visible light irradiation. Furthermore, we found that prolonging the holding time made Cu₂O microspheres transform to polyhedrons