Shape controlled synthesis and optical properties of Cu2O micro-spheres and octahedrons

Cuprous oxides (Cu2O) spheres and octahedron were synthesized through hydrazine (N2H4) reduction to Cu2+ sources using polyvinyl pyrrolidone (PVP) as the capping reagent. Methyl orange (MeO) was used as the target to evaluate the photocatalysis properties. Cu2O particles with sizes ranged in 0.4 pm and 05 pm can be obtained through reducing Cu(OH)(2) or brochantite (Cu-4(SO4)(OH)(6.2)H2O) when mole ratio of Cu2+/N2H4 was set at 2.0. Lyophilizing is a critical and fairly good drying method to obtain pure Cu2O. Octahedrons can be obtained at high temperature (60 C), low resources concentrations (NaOH, Cu-2 and N2H4) and small PVP dosage, while the micro -spheres were received at ambient circumstances, higher concentrations and larger PVP dosage. Optical absorption spectra of spherical Cu2O showed the absorption edge at 590 nm while octahedrons shifted to 602 nm. Photocatalysis results revealed that 95% MeO can be decolorized in 40 min by the spherical Cu2O, while the efficiency was 50% for the octahedra. (C) 2015 Elsevier Ltd. All rights reserved.