Synthesis of Iron Oxide Nanostructures by Annealing Electrodeposited Fe-Based Films

We report the self-assembly of microsized nanowalls and nano-/micropatterns of magnetic iron oxides upon the oxidation of electrodeposited Fe-based films when annealed in air at temperatures ranging from 300 to 450 °C. Scanning electron microscope studies indicate that these nanowalls have the thinnest wall of down to ∼8 nm with a length up to ∼2 μm and a height reaching ∼6 μm; the square patterns have an area of 0.06−1.0 μm 2 . The generated nanowalls can be used to detect O 2 or H 2 at high temperatures via their resistance change. The simple spontaneous synthesizing procedure reported here can be applied as well to other electro-/electroless-deposited metal films to form zero-, one-, and two-dimensional metal-based nanostructures.