Synthesis and Application of Noble Metal Nanocatalysts Supported on MgAl2O4 in Glycerol Dry Reforming Reaction

Noble metal catalysts (Rh, Ru, Ir, Pd, Pt) supported on alumina-stabilized magnesia (MgAl2O4) were prepared and employed in order to convert glycerol to syngas in the presence of carbon dioxide. The physiochemical properties of the fresh and spent catalysts were determined using BET, TPR, TPO, TEM and H2S chemisorption techniques. The BET analysis showed higher surface area for the Rh, Ru and Pd catalysts compared to other samples. The TEM images of the prepared catalysts exhibited that the sizes of the active metals are smaller than 5 nm with high dispersion on the surface of the catalyst carrier. The H2S chemisorption results showed that the crystallite sizes of the noble metals were in the range of 1.28-4.2 nm. The catalytic results showed that the Rh catalyst exhibited the highest activity and stability in this reaction. The high activity of Rh catalyst could be attributed to its high BET and active metal areas. The catalytic activity of Rh catalyst declined with time on stream due to the carbon formation. It was seen that increasing the CO2 to glycerol ratio (CGR) from 0 to 3 improved the catalytic activity and decreased the amount of deposited carbon on the catalyst surface.