Sol–Gel Synthesis of Tunable Cerium Titanate Materials

Abstract

Abstract Cerium titanate structures present a high technological interest because of their optical and catalytic properties. This work reports the synthesis of these materials by a sol–gel methodology that allows mixed oxides with Ti IV /Ce III , Ti IV /Ce IV or Ti IV /Ce III –Ce IV species to be obtained. Crystallization of CeO 2 –TiO 2 mixed oxides and Ce 2 Ti 2 O 7 pyrochlore phase was corroborated by XRD and Raman spectroscopy. Magnetic and EPR measurements were performed in order to clarify the oxidation state of the cerium ions in the system as a result of the easy oxidation of Ce III . The firing atmosphere is crucial for the Ce III /Ce IV ratio, which is responsible for the different structure, but it also affects the colouration (yellow, green, brown). This methodology offers the possibility to modulate the Ce 3+ /Ce 4+ content and particle sizes providing more ecological coloured pigments based on rare earth elements that could be interesting materials for advanced applications in catalysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)