Figure 2

(a) TEM image of a typical nanodisc and its corresponding diffraction pattern. (b,c) HRTEM image on the inner and border of the disc. (d–g) EDX mapping of one top-view nanodisc and its Co and Ni mapping and elemental distribution illustration model. (h–k) EDX mapping of one side-view nanodisc and its Co and Ni mapping and its elemental distribution illustration model.