Sculpting nanocavities via thermal stimulated Kirkendall effect oxidation

Controlling the shape, morphology, and porosity of hollow nanostructures is a pivotal issue for adjusting the characteristics of tailor-made nanomaterials to expand their application to more fields. Although many hollow metal oxides have been developed, studies on the construction of hollow bimetal oxide heterostructures with controllable nanocavities in different morphologies and high crystallinity through Kirkendall effect is still ascendant. Using this strategy, nickel nanotubes with smooth walls was acquired through continuous oxidation treatments on CuNi nanowires at 200 °C. Oxidation treatment at high temperature (300 °C) on CuNi nanowires produced nickel oxide nanotubes containing periodic copper nanoparticles, nickel oxide nanotubes with a bamboo-like structure and nanoforests. In addition, thin CuO nanowires with diameters of 5–10 nm grew on nanowires at 400 °C. Finally, the mechanisms of sculpting nanocavities at high and low temperatures were elucidated. An in-depth understanding of the thermally stimulated Kirkendall effect in bimetals has a significant influence on the design and fabrication of new hollow multifunctional hetero-nanostructures with potential applications in energy storage, catalysis, and gas sensing. [Display omitted] •Different hollow heterostructures were obtained by controlling the oxidation time and temperature of CuNi nanowires.•At 200 °C, nickel nanotubes with uniform wall thickness was acquired.•At 300 °C, nickel oxide nanotubes containing periodic copper nanorods and nanoforests were obtained.•The mechanisms of sculpting nanocavities at high and low temperatures were elucidated.