X-ray Diffraction and Atomic Force Microscopy of RuO2 thin films

X-ray Diffraction data of the RuO2 samples were obtained to assess the crystallinity and epitaxial nature of the thin films grown on different substrates. Atomic Force Microscopy was used to determine the surface morphology changes as a function of thickness and epitaxial strain and correlate it with the observed oxygen evolution activity.

X-ray Diffraction 2theta-omega couples scans for RuO2 on r-Al2O3 (Supplementary Figure 1 a) of different thicknesses. Similar data is used for comparing RuO2 films with comparable thickness grown on r-Al2O3 and TiO2 (101) substrate (Supplemetary Fig 6b). Atomic Force Microscopy images acquired using a Bruker multimode for comparing surface morphology change as a function of thickness of RuO2 film grown on r-Al2O3 substrate (Supplementary Fig 1 b)