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Effects of reaction temperature and feed composition on reactant conversion, product distribution and catalytic stability were investigated on syngas production by reforming of glycerol, a renewable waste, with CO 2 on Rh/ ZrO 2 and Rh/CeO 2 catalysts. For the first time in the literature, fresh and spent catalysts were characterized by in-situ FTIR, Raman spectroscopy, transmission electron microscopy and energy dispersive X-ray analysis techniques in order to unravel novel insights regarding the molecular-level origins of catalytic deactivation and aging under the conditions of glycerol dry reforming. Both catalysts revealed increased glycerol conversions with increasing temperature, where the magnitude of response became particularly notable above 650 and 700°C on Rh/ZrO 2 and Rh/CeO 2 , respectively. In accordance with thermodynamic predictions, CO 2 transformation occurred only above 700°C. Syngas was obtained at H 2 /CO ∼0.8, very close to the ideal composition for Fischer-Tropsch synthesis, and carbon formation was minimized with increasing temperature. Glycerol conversion decreased monotonically, whereas, after an initial increase, CO 2 conversion remained constant upon increasing CO 2 /glycerol ratio (CO 2 /G) from 1 to 4. In alignment with the slightly higher specific surface area of and smaller average Rh-particle size on ZrO 2 , Rh/ZrO 2 exhibited higher conversions and syngas yields than that of Rh/CeO 2. Current characterization studies indicated that Rh/CeO 2 revealed strong metal-support interaction, through which CeO 2 seemed to encapsulate Rh nanoparticles and partially suppressed the catalytic activity of Rh sites. However, such interactions also seemed to improve the stability of Rh/CeO 2 , rendering its activity loss to stay below that of Rh/ZrO 2 after 72 h time-on-stream testing at 750°C and for CO 2 /G = 4. Enhanced stability in the presence of CeO 2 was associated with the inhibition of coking of the catalyst surface by the mobile oxygen species and creation of oxygen vacancies on ceria domains. Deactivation of Rh/ZrO 2 was attributed to the sintering of Rh nanoparticles and carbon formation.

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