Lithography inside Cu(OH)2 nanorods: a general route to controllable synthesis of the arrays of copper chalcogenide nanotubes with double walls.

A series of well-aligned arrays of copper chalcogenide nanostructures, including Cu(7)S(4) and Cu(2-x)Se nanotubes with double walls have been successfully prepared by using Cu(OH)(2) nanorods as sacrificial templates. This new method is based on layer-by-layer chemical conversion and inward etching of the sacrificial templates, which is essentially a kind of lithography inside the Cu(OH)(2) nanorods. The key step of the process involves repeated formation of the copper chalcogenide wall and the dissolution of the Cu(OH)(2) core for two consecutive cycles. A large difference of the solubility product (Ksp) between the copper chalcogenide wall and the Cu(OH)(2) core materials is crucial for the direct replacement of one type of anions by the other. Our work provides a novel and general approach to the controllable synthesis of the arrays of copper chalcogenide nanotubes with double walls and complex hierarchies.