Morphology-Dependent Catalytic Activity of Ru/CeO₂ in Dry Reforming of Methane.

Three morphology-controlled CeO₂, namely nanorods (NRs), nanocubes (NCs), and nanopolyhedra (NPs), with different mainly exposed crystal facets of (110), (100), and (111), respectively, have been used as supports to prepare Ru (3 wt.%) nanoparticle-loaded catalysts. The catalysts were characterized by H₂-temperature programmed reduction (H₂-TPR), CO⁻ temperature programmed desorption (CO-TPD), N₂ adsorption⁻desorption, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (XDS). The characterization results showed that CeO₂-NRs, CeO₂-NCs, and CeO₂-NPs mainly expose (110), (100) and (111) facets, respectively. Moreover, CeO₂-NRs and CeO₂-NCs present higher oxygen vacancy concentration than CeO₂-NPs. In the CO₂ reforming of methane reaction, Ru/CeO₂-NR and Ru/CeO₂-NC catalysts showed better catalytic performance than Ru/CeO₂-NPs, indicating that the catalysts with high oxygen vacancy concentration are beneficial for promoting catalytic activity.