MAPEX Research Highlights

Unraveling the Dynamic Nanoscale Reducibility (Ce4+ → Ce3+) of CeOx–Ru in Hydrogen Activation

Jan Höcker, Tevfik Onur Mentes, Alessandro Sala, Andrea Locatelli, Thomas Schmidt, Jens Falta, Sanjaya D. Senanayake and Jan Ingo Flege.

Advanced Materials Interfaces (2015) 2, 1500314.

doi:10.1002/admi.201500314

The interaction of molecular hydrogen with ceria is of important relevance for heterogeneous catalysis related to green chemistry and renewable energy. Here, the complex structural transformations of a well-defined cerium oxide model catalyst are followed in situ and in real time when exposed to a reactive H2 environment. By using electron spectromicroscopy and diffraction with chemical and structural sensitivities, it is demonstrated that the transition from CeO2 to crystalline Ce2O3 occurs through a mixture of transient, coexisting phases on the nanoscale. The findings establish a clear relationship between structure and functionality for hydrogen dissociation over ceria(111), bearing profound implications on the nature of the reduction (Ce4+ → Ce3+) and mechanism for H2 scission.

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