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 similar to 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.