Electronic exchanges between adsorbed Ni atoms and TiO2(1Â 1Â 0) surface evidenced by resonant photoemission

► Reactivity of nickel atoms towards TiO2(1 1 0) surface is revealed for fractional monolayer coverage. ► Resonant photoemission at the Ti 3p → 3d edge shows electronic transfer between Ni and titanium ions. ► For coverage higher than 0.14 eqML no reaction is revealed leading to metallic nickel clusters.