Environmental remediation of Direct Blue dye solutions by photocatalytic oxidation with cuprous oxide

Highlights: •Cu2O was prepared via hydrothermal method. •The effect of hydrothermal temperatures on the morphology of products were investigated. •Cu2O nanorod exhibited the highest catalytic activity for Direct Blue dye under visible light. -- Abstract: A simple hydrothermal route has been developed to synthesize shape-controllable Cu2O from starting materials of CuCl2·2H2O and NaOH by changing the hydrothermal temperature from 80 to 140 °C. Cu2O nanorods, a mixture of nanorods and nanocubes or nanocubes have been synthesized by controlling the hydrothermal temperature. The experiments demonstrate that the hydrothermal temperature is an important parameter that may determine whether the Cu2O is shaped as nanorods, a mixture of nanorods and nanocubes or nanocubes. The products were characterized with X-ray diffraction (XRD), ultraviolet and visible spectroscopy (UV–vis), transmission electron microscopy (TEM) and surface area measurements. Furthermore, the photocatalytic performance of Cu2O was measured in the degradation of Direct Blue dye with visible light