Effect of ceria morphology on the catalytic activity of Ru/ceria for the dehydrogenation of ammonia borane

- The catalysts exhibit a support-morphology-dependent catalytic activity behavior.
- The activity follows the order of Ru/c-CeO2 > Ru/r-CeO2 > Ru/o-CeO2.
- This order is different from the order observed in other catalytic reactions.
- This order is comprehensively influenced by the interaction and the surface area.

Although the effect of CeO2 morphology on catalytic properties has been studied, research interests mainly focus on the oxidation reactions while the effect of CeO2 morphology on other reactions, such as dehydrogenation reaction, has rarely been reported. In this study, the dehydrogenation of ammonia borane (AB) was chosen as a model reaction to study the effect of CeO2 morphology (“c”, “r” and “o” denote cube, rod, and octahedron, respectively) on the catalytic properties of Ru/CeO2. Our study shows that the activity follows the order of Ru/c-CeO2 > Ru/r-CeO2 > Ru/o-CeO2, which is different from the order observed in other catalytic oxidation reactions. X-ray photoelectron spectroscopy (XPS), Raman and H2-Temperature program reduction (H2-TPR) measurements reveal that there is a weak interaction between Ru and c-CeO2, and metallic Ru is the dominant species in Ru/c-CeO2, which are possibly responsible for the highest catalytic activities among three Ru/CeO2 catalysts.

The effect of ceria morphology on the catalytic properties of Ru/ceria for the dehydrogenation of ammonia borane was studied. The catalytic activity follows the order of Ru/c-CeO2 > Ru/r-CeO2 > Ru/o-CeO2, which is not only different from the one in oxidation reactions, but also different from the one in hydrogenations. This work would help us further understand the hydrolysis mechanism and support-morphology-reactivity relationship of the dehydrogenation of ammonia borane.328