Shape-controlled synthesis of Cu2O nanocrystals assisted by Triton X-100

Cuprous oxide (Cu2O) nanocrystals with tubular, cubic and hollow cubic morphologies were obtained in simple solution-phase reduction systems using nonionic surfactant octylphenyl ether (Triton X-100) as solvent. Uniform single crystal nanotubes with outer diameters of ∼20 nm, inner diameters of ∼10 nm and lengths of ∼120 nm were prepared through reduction of CuCl2 by glucose. When a little amount of water was dispersed into Triton X-100, uniform cube-shaped polycrystals with edge lengths of ∼180 nm were synthesized, with ascorbic acid as the reducing agent. The water cores formed by surrounded Triton X-100 molecules with hydrophilic heads immersed provided the reaction rooms. With the help of ethanol introduced into water cores by Triton X-100 molecules, Cu2O nanocubes turned to hollow cubes with edge lengths of ∼200 nm during the ripening process. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) were used to investigate the different morphologies of the as-synthesized products. X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) were applied to characterize the composition and crystal phases of the products. It was proposed that molecules and molecule assemblies of Triton X-100 played different roles in the shape-controlled synthesis process, which were realized by carefully controlling the experiment conditions.