Without any assistance of surfactant and/or template the hexagonal prism-shaped Cu2+-doped ZnO (Zn(Cu)O) microcrystals with twinned structures were easily synthesized by one-step co-precipitating under atmospheric pressure and moderate temperature, in which Cu2+ ion was used as the dopant and the morphology controller. Because Cu2+ ions can be adsorbed on the (0001) and {10 (1) over bar1} planes the growth on these planes was restrained, resulting in the formation of Zn(Cu)O microcrystals with stubby hexagonal prism shape. Meanwhile, the twinned structure Zn(Cu)O microcrystals were obtained via the electrostatic interaction between adsorbed Cu2+ ion and two (000 (1) over bar) negative planes. When twinned structure Zn(Cu)O sample was etched by NaOH solution the (0001) polar planes at two ends of Zn(Cu)O crystal were dissolved via forming Zn(OH)(4)(2-) complex ion, but the non-polar {0110} planes did not. As a result, the tubular structure Zn(Cu)O microcrystals (T-Zn(Cu)O) were obtained in the absence of template and/or specific protective agent. The metallic Ag decorated tubular Zn(Cu)O (T-Zn(Cu)O/Ag) samples were prepared by auto-catalyzed deposition reaction. The morphological, structural, photoluminescence, as well as photocatalytic properties of Zn(Cu)O, T-Zn(Cu)O and T-Zn(Cu)O/Ag samples were investigated and the results indicated that the Zn(Cu)O sample with a very small amount of doped Cu2+ ion showed higher photocatalytic activity than ZnO. Tubular structure Zn(Cu)O samples showed moderately enhanced photocatalytic activities compared to corresponding Zn(Cu)O samples. By decorating metallic Ag on the surfaces the T-Zn(Cu)O/Ag samples exhibited distinctly enhanced photocatalytic activities due to the contribution of Schottky barrier and intensive light-absorption in Vis and NIR regions. (C) 2015 Elsevier B.V. All rights reserved.