Fig. 1: Morphology and structure characterizations of as-synthesized Ru/TiOx.

a Schematic illustration of synthesis of Ru/TiOx as binder-free electrode towards oxygen evolution reaction (OER) in acidic media. b Transmission electron microscopy (TEM) image of Ru/TiOx and corresponding energy dispersive X-ray spectroscopy (EDS) mapping profile of Ti (blue) and O (red). c Aberration-corrected high angle annular dark field-scanning TEM (HAADF-STEM) image of Ru/TiOx and corresponding EDS mapping profile of Ru (yellow), Ti (blue) and O (red). d, e Aberration-corrected HAADF-STEM images of TiOx support (d) and Ru site of Ru/TiOx (e). STEM intensity profiles are presented to directions labeled with blue (α) and red (β) arrows. (α and β) show the corresponding intensity profiles and the lattice fringe spacing.