Fabrication of copper micro-tubes by electroless deposition with an etched porous aluminum template without using sensitization and activation

Cu micro-tubes were fabricated by electroless deposition in an etched porous aluminum membrane without sensitization and activation. The aluminum membrane having square holes was prepared from a high-purity aluminum foil electrochemically. The aluminum reduced Cu2+ into Cu and the formed Cu nuclei served as the catalyst for the further reduction of Cu2+. The auto-catalysis substituted the preparation of a novel metal catalyst through sensitization or activation and greatly simplified the deposition process. A two-step operation was developed to improve the deposition of copper, which enhanced the deposition reaction inside the micro-pores. With the help of the membrane, Cu micro-tubes with an outer diameter of about 1–2 μm and a wall thickness in the order of tens to several hundreds nanometers were obtained. The surface-deposited copper layer served as a substrate for the copper micro-tubes, and as the result the resulted material possessed strong mechanical strength as well as high surface area.