Microwave-Assisted Synthesis of Ultrastable Cu@TiO2 Core-Shell Nanowires with Tunable Diameters via a Redox-Hydrolysis Synergetic Process

Abstract

The nanoscale integration of copper metal, frequently with semiconductor heterostructure interfaces, is a promising route for fabricating new micro-/nanoelectronic devices. Synthesizing such systems using wet-chemistry methods requires stabilization of nano-Cu against corrosion/oxidation, which has proven to be challenging. Here we report a methodology for the facile preparation of Cu@TiO2 core-shell nanowires (NWs). The synthesis combines redox formation of Cu NWs with kinetically controlled hydrolysis of a titania precursor in a single-pot microwave reaction. The final core-shell NWs can be precisely tailored with 20-nm to 140-nm Cu core diameters, aspect ratios >250, and a 10-nm porous titania shell. This metal/semiconductor heterojunction is particularly important for its excellent photocatalytic activity. The rapid microwave-assisted synthesis provides a potentially generalizable paradigm for the rational design of heterogeneous nanostructures with metals and oxides.