Fig. 3From: A Facile Method for Preparation of Cu2O-TiO2 NTA Heterojunction with Visible-Photocatalytic ActivityTypical SEM images of pure TiO2 nanotube arrays without modification. a Top view and b side view, indicating the highly ordered vertical alignment structure with open-tube mouth morphology. The tube diameter is about 100 nm, and the tube length is about 10 μmBack to article page