Alumina-supported VO x -TiO 2 materials are synthesized by atomic layer deposition (ALD) and characterized by diffuse reflectance UV-vis (DRUV-vis) spectroscopy, Raman spectroscopy, and density functional theory (DFT) calculations in order to identify the metal oxide structures present on the surface of the support. Preferential binding of VO x to TiO 2 domains is demonstrated by Raman spectroscopy studies and confirmed by DFT. Varying distributions of V-O-Ti, V-O-V, and V-O-Al bonds are present in the examined materials. The interactions of VO x and TiO 2 are elucidated further under a reducing, H 2 environment at elevated temperatures. An enhancement in reducibility of VO x species is expected and observed upon the modification of alumina with TiO 2 above monolayer coverages, but also when a single ALD cycle of TiO 2 is deposited following the deposition of VO x on the support. X-ray photoelectron spectroscopy (XPS) detects changes in the oxidation state of vanadium, but not titanium during reduction. Reversible migration and aggregation of V and Ti atoms is also detected upon heating in H 2 .
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films