Exceptionally active and stable catalysts for CO2 reforming of glycerol to syngas

Abstract

CO2 reforming of glycerol to syngas was studied on Al2O3-ZrO2-TiO2 (AZT) supported Rh, Ni and Co catalysts within 600–750 °C and a molar inlet CO2/glycerol ratio (CO2/G) of 1–4. Glycerol and CO2 conversions decreased in the following order: Rh/AZT > Ni/AZT > Co/AZT. Reactant conversions on Rh/AZT exceeded 90% of their thermodynamic counterparts at 750 °C and CO2/G = 2–4 at which the activity of Ni/AZT was boosted to ˜95% of the thermodynamic CO2 conversion upon increasing the residence time. The loss in CO2 conversions was below 13% during the 72 h longevity tests confirming the exceptional stability of Rh/AZT and Ni/AZT. However, Co/ AZT suffered from sintering, carbon deposition and oxidation of Co sites, demonstrated via TEM-EDX, XPS, XANES and in-situ FTIR experiments. Characterization of Rh/AZT revealed no significant signs of deactivation. Ni/AZT preserved most of its original metallic pattern and gasified carbonaceous deposits during earlier stages of the reaction