ZnO@Co hybrid nanotube arrays growth from electrochemical deposition: structural, optical, photocatalytic and magnetic properties.

Well-aligned ZnO@Co hybrid nanotube arrays on conductive glass substrates have been obtained by an electrochemical deposition approach. Vertical-aligned ZnO nanotubes with sizes between 300 and 600 nm in diameter and wall thickness of approximately 100 nm have been prepared by selective dissolution from the nanorods. The ZnO@Co heterostructures can be prepared by optimizing the deposition time and controlling the stability of Co2+ ions. Compared to the nanorod arrays, both nanotube arrays and the ZnO@Co heterostructures show enhanced photoluminescent properties. In addition, ZnO and ZnO@Co nanotubes show improved photocatalytic properties compared with the bare ZnO nanorod array, and the hybrid nanotubes exhibit better adsorptive properties than the bare ZnO nanotubes. Furthermore, the ZnO@Co hybrid nanotube arrays show ferromagnetism at room temperature.