Fig. 3. A TEM micrograph of Au–Ni core–shell nanoparticles with varying shell thicknesses: (a) 0.375 C cm⁻² – 60 nm, (b) 0.75 C cm⁻² – 120 nm and (c) 1.5 C cm⁻² – 220 nm. The particles in (a)–(c) were imaged by HAADF-STEM as shown in (d)–(f) and analyzed by EDX line scan along the white line in the center. (g) Elemental line scan of a particle in (f). (h) A plot of shell growth as a function of deposition charge passed. The shell thickness distribution was obtained by statistical processing of the EDX line scans and HAADF-STEM micrographs. The scale bars are 500 nm.