Fig. 1: TEM characterization of Pd@Au core–shell nanocubes.

a Low-magnification and b high-magnification STEM-HAADF images of Pd@Au nanocubes (44-nm core and 35-nm shell). c–e STEM-EDX results of Pd@Au nanocubes with elemental maps for Pd c, Au d and their overlay e. Scale bars: 200 nm a, c–e and 20 nm b.