Investigation of active species in methanation reaction over cerium based loading

A series of cerium oxide based catalyst has been studied by various cerium loadings that calcined at 1000oC using wet impregnation method. The potential Ru/Mn/Ce (5:35:60) /Al2O3 catalyst calcined at 1000oC was characterized using XRD, XPS, and BET analyses. As could be observed from the XRD analysis, at Ce ratio of 55% and 65%, both revealed the presence of RuO2 with tetragonal phase and intense, sharper peaks indicating to high crystallinity and in line with lower surface area, 50.95 m2/g in BET analysis. Meanwhile, CeO2 (cubic phase) and MnO2 (tetragonal phase) were also observed for 55%, 60%, and 65%, respectively. However, the presence of Al2O3 with rhombohedral phase at 55% and 65% was revealed as an inhibitor which decreased the CO2 conversion. The presence of active species on Ru/Mn/Ce (5:35:60) /Al2O3 catalyst has been confirmed using XPS analysis with the deconvolation peaks belonged to Ce4+ with the formation of CeO2 compound and Mn4+ for MnO2. The product formed in catalytic methanation was proposed to be H2O and CH3OH from GC and HPLC analysis