Design of Lewis Pairs via Interface Engineering of Oxide-Metal Composite Catalyst for Water Activation

The rational design and controlled construction of active centers remain grand challenges in heterogeneous catalysis, in particular for oxide catalysts with complex surface and interface structures. This work describes a facile way in the design of highly active Ni-O Lewis pairs for water activation where Ni and O sites act as Lewis acid and base, respectively. Surface science experiments indicate that dissociative adsorption of water occurs at edges of NiO nanoislands grown on Au(111) and NiO-Ni interfaces formed by further depositing metallic Ni layers along the edges of NiO nanoislands. Enhanced activity of Ni-O Lewis pairs at the NiO-Ni interface has been demonstrated by theoretical calculations, which are attributed to the higher Lewis acidity of metallic Ni sites and synergy of the metal and oxide components. Moreover, proton can migrate away from the NiO-Ni interface and refresh the O base sites, leading to further hydroxylation of the neighboring Ni acid sites.