Synthesis of iron oxide nanostructures by annealing electrodeposited Fe-based fillms

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 degrees C. Scanning electron microscope studies indicate that these nanowalls have the thinnest wall of down to similar to 8 nm with a length up to similar to 2 mu m and a height reaching similar to 6 mu m; the square patterns have an area of 0.06-1.0 mu m(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.