Activation of Oxygen on MgO: O₂^.− Radical Ion Formation on Thin, Metal‐Supported MgO(001) Films

Abstract

Distortion is the key: In situ EPR spectroscopy provides the first experimental confirmation that the adsorption of O2 molecules on a stoichiometric ultrathin MgO(001) film on Mo(001) leads to the spontaneous formation of O2.− radicals. The results show that polaronic distortion of the MgO lattice (see picture; Mg yellow, O blue) stabilizes the radical, and this distortion is only possible in very thin films.