A highly active and stable Ru catalyst for syngas production via glycerol dry reforming: Unraveling the interplay between support material and the active sites

Glycerol dry reforming (GDR) was studied on Ru/La2O3, Ru/ZrO2, and Ru/La2O3-ZrO2 catalysts. Impacts of the support on morphological, electronic and surface chemical properties of the catalysts were comprehensively characterized by TEM, in-situ DRIFTS, XPS, ATR-IR and XRD. Initial (5 h) CO2 conversion at 750 C and CO2-to-glycerol ratio of 1-4 was ordered as Ru/La2O3 < Ru/ZrO2 < Ru/La2O3-ZrO2. During 72 h stability tests, Ru/ZrO2 deactivated by similar to 33% due to Ru sintering, structural deformation of the monoclinic zirconia support, and strong metal-support interaction. Under identical conditions, CO2 conversion on Ru/La2O3 decreased by 27% mainly due to dehydroxylation/carbonation of lanthana and severe coking. Lanthana-stabilized tetragonal zirconia phase of Ru/La2O3-ZrO2 led to finely dispersed small oxidic Ru clusters which deactivated by 15% after 72 h and demonstrated unusually high catalytic performance that was on par with the significantly more expensive Rh-based catalysts, which are known with their exceptional activity and stability in GDR.