Room Temperature Engineering Crystal Facet of Cu2O for Photocatalytic Degradation of Methyl Orange

Cuprous oxide (Cu2O) has received enormous interest for photocatalysis owing to its narrow band gap of 2.17 eV, which is beneficial for visible-light absorption. In this work, we succeeded in synthesizing Cu2O nanocrystals with two morphologies, cube and sphere, at room temperature via a simple wet-chemistry strategy. The morphologies of Cu2O change from cube to sphere when adding PVP from 0 g to 4 g and the mainly exposed crystal faces of cubic and spherical Cu2O are (100) and (111), respectively. The photocatalytic properties of the as-prepared Cu2O were evaluated by the photocatalytic degradation of methyl orange (MO). Cubic Cu2O(100) showed excellent photocatalytic activity. After the optical and photoelectric properties were investigated, we found that cubic Cu2O(100) has better photoelectric separation efficiency than spherical Cu2O(111). Finally, the possible mechanism was proposed for cubic Cu2O(100) degrading MO under visible light.