Abstrakt
Ceria containing highly dispersed ions of rhodium is a promising material for catalytic applications. The Rh-CeOx thin films with different concentrations of rhodium were deposited by RF magnetron sputtering and were studied by soft and hard X-ray photoelectron spectroscopies, Temperature programmed reaction and X-ray powder diffraction techniques.
The sputtered films consist of rhodium-cerium mixed oxide where cerium exhibits a mixed valency of Ce4+ and Ce3+ and rhodium occurs in two oxidation states, Rh3+ and Rhn+. We show that the concentration of rhodium has a great influence on the chemical composition, structure and reducibility of the Rh-CeOx thin films.
The films with low concentrations of rhodium are polycrystalline, while the films with higher amount of Rh dopants are amorphous. The morphology of the films strongly influences the mobility of oxygen in the material.
Therefore, varying the concentration of rhodium in Rh-CeOx thin films leads to preparing materials with different properties. (C) 2015 Elsevier Ltd. All rights reserved.