Cerium dioxide is widely used as carrier on which noble metals are dispersed to act as catalysts for a range of reactions. One of the most widely used applications of this material is in the automobile-exhaust system where it converts toxic gases, in particular carbon monoxide & nitrogen oxides, to benign gases. Therefore, cerium dioxide is widely studied as it has unusual chemical behaviour under reaction conditions. While several studies have focused on the structural chemistry, it has not been fully understood how this material reduces or whether a transient reduced state exists in the presence of noble metals. Scattering techniques are powerful in allowing us to determine where the cerium and oxygen ions are located in the material under operating conditions. Here we will perform neutron scattering experiments to follow the structural changes in the cerium dioxide system.