Rhodium particles supported by thin vanadia films as model systems for catalysis: An electron microscopy study

A treatment in 1 bar O2 between 300 and 573 K converts the supporting oxide into mixed V2O3, VO2 and V2O5 phases. Oxidation at 673 K induces a complete reconstruction into a single V2O5 phase, while an oxygen treatment at 723 K transforms also the Rh particles into (β)Rh2O3. Reduction of the bare V2O5 film in 1 bar hydrogen yields cubic VO at 673 K, but reduction of the Rh/V2O5 film leads to VO formation already at 473 K. Finally, a reduction of vanadia-supported Rh particles at and above 573 K results in the formation of Rh/V alloy structures.