Fig. 1: Synthesis and structural characterization of PtRuNi-Ox catalyst.

a Schematic diagram of the solvothermal synthesis method of PtRuNi-Ox catalyst. b HAADF-STEM, c TEM images of PtRuNi-Ox, and magnified HAADF-STEM images of a typical nanocage in the inset. d, e Atomic phase images of PtRuNi-Ox, FFT patterns generated from e in the inset. f HRTEM images of PtRuNi-Ox shows the lattice fringes with interface sign. g Magnified HAADF-STEM images of the interface framework and the corresponding atomic strength profile analysis, and the red dashed circles represent atomic defects at the boundary. h EDS mapping images of PtRuNi-Ox.