2D Ni Nanoclusters on Ultrathin MgO/Ag(100)

Ni nanoclusters up to 30 angstrom in diameter are grown by Ni deposition on ultrathin MgO/Ag(100) films at different temperatures and characterized by combining low-temperature scanning tunneling microscopy with photo-emission and vibrational spectroscopies. At 200 K, both small NixOyD aggregates and 2D Ni nanoparticles of average size close to 12 angstrom form. The latter have a metallic nature and efficiently catalyze CO dissociation at 200 K. When Ni is deposited at 300 K, only larger 3D Ni clusters are observed.