Effective dispersion of the active species over the support almost always guarantees high catalytic efficiency. To achieve this high dispersion, favourable interaction of the active species with the support is crucial. We show here that the crystal structure of the titania support determines the interaction and consequently the nature of Ru deposited on the support. Similar crystal structures of RuO₂ and rutile titania lead to a good lattice matching and ensure a better interaction, maintaining the initial good dispersion of the active species on the support and leading to better activity and selectivity. This highlights the importance of understanding the physico-chemical processes during catalyst preparation steps.