Epitaxial NiWO 4 films on Ni(110): Experimental and theoretical study of surface stability

摘要: Despite the application potential of nickel tungstate (NiWO4) in heterogeneous catalysis, humidity and gas sensing, etc, its surfaces have essentially remained unexplored. In this work, NiWO4 nanoparticles films with wolframite structure been grown via a solid-state reaction (WO3)3 clusters NiO(100) film on Ni(110) crystal surface characterized by variety experimental techniques, including x-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM) diffraction (XRD), combined ab-initio density functional theory (DFT) calculations. grows initially as three-dimensional (3D) crystalline displaying mainly two facets vicinal to (100) surface, which merge increasing coverage into quasi-continuous epitaxial film. The DFT results provide an account energetics low index highlight role faceting stabilization extended polar terraces. These theoretical show that interaction metal substrate vertical confinement may stabilize oxide nano-objects high energy facets, able enhance their reactivity.