Acidities of CeO2 and Ce0.5Zr0.5O2 solid solutions studied by NH3-TPD

Ammonia temperature-programmed desorption (NH3-TPD) was used to study the a cidities of CeO2 and Ce0.5Zr0.5O2 solid solutions. The NH3-TPD peaks of bat h CeO2 and Ce0.5Zr0.5O2 exist at 100-850 degrees C. The ratio of the lower and middle temperature peak areas to the higher temperature peak is decreas ed for Ce0.5Zr0.5O2 relative to CeO2 under all pretreatment conditions, whi ch suggests that Ce0.5Zr0.5O2 has more acid sites of higher energy than CeO 2, This may be one of the reasons why Ce0.5Zr0.5O2 is a more highly efficie nt catalyst for methane combustion than CeO2, Copyright (C) 1999 John Whey & Sons, Ltd.