We present experimental and theoretical evidence of sequential redox processes and structural transformations occurring by increasing temperature in a metal/oxide/metal system obtained via deposition of Fe atoms onto a z′-TiO1.25/Pt(111) ultrathin film in UHV. The initial reduction of the z′-TiOx phase by Fe at room temperature is followed by Fe diffusion and partial penetration into the substrate at intermediate temperatures. This triggers the formation of a bi-component material in which mixed FeO/TiO2 nanoislands coexist on a h-TiO1.14 ultrathin film, notably restructured (from rectangular to hexagonal) and reduced (from Ti:O = 1:1.25 to 1:1.14) with respect to the original TiO1.25 phase. Further heating recovers the pristine z′-TiOx phase while Fe completely dissolves into the substrate.
Tracking thermally-activated transformations in a nanostructured metal/oxide/metal system
ARTIGLIA, LUCA;RIZZI, GIAN-ANDREA;GRANOZZI, GAETANO
2011
Abstract
We present experimental and theoretical evidence of sequential redox processes and structural transformations occurring by increasing temperature in a metal/oxide/metal system obtained via deposition of Fe atoms onto a z′-TiO1.25/Pt(111) ultrathin film in UHV. The initial reduction of the z′-TiOx phase by Fe at room temperature is followed by Fe diffusion and partial penetration into the substrate at intermediate temperatures. This triggers the formation of a bi-component material in which mixed FeO/TiO2 nanoislands coexist on a h-TiO1.14 ultrathin film, notably restructured (from rectangular to hexagonal) and reduced (from Ti:O = 1:1.25 to 1:1.14) with respect to the original TiO1.25 phase. Further heating recovers the pristine z′-TiOx phase while Fe completely dissolves into the substrate.Pubblicazioni consigliate
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