Observation of Functional Groups in Ceria Crystal under Hydrogen Addition Reaction by in Situ Neutron Scattering Measurements

Monitoring chemical reactions between solid and gas is important not only in general chemistry but also in industrial applications. Ceria （CeO2） is a well-known material used in various industrial and environmental applications. Ceria was kinetically reduced in hydrogen depending on the isothermal holding time at high temperature. Neutron powder diffraction analysis revealed that ceria transformed into the oxyhydroxide structure CeO2Hy（0 ≤ y ≤ 1） by hydrogen treatment. Due to detection of the vibrational modes of both OH and CeH functional groups by inelastic neutron scattering measurements, the CeH functional group was revealed to possibly exist in ceria as an aperiodic structure.