Characterization of iron-doped mesoporous silica nanoparticles for CO2 methanation

Abstract

Fe metal catalysts supported on mesoporous silica nanoparticles (MSN) with various Fe loadings (1-15 wt%) have been prepared by the incipient wetness impregnation method. The results obtained revealed that increasing Fe loading (1– 15 wt.%) decreased the crystallinity of MSN and N2 adsorption as evidenced by XRD and N2 physisorption, respectively. 29Si NMR results showed that increasing Fe loading affected the arrangement of the Si atom by increasing the population of Q2 with a concomitant decrease of Q3 and Q4. The addition of Fe on MSN also increased the mononuclear cations, oligomeric and bulky Fe oxide (Fe2O3) species in MSN. The catalyst activities on CO2 methanation followed the order 10Fe/MSN > 15Fe/MSN > 5Fe/MSN > 1Fe/MSN. The high activity of 10Fe/MSN may be related to its structural properties tailored by all Fe species on the MSN surface. Based on these results, it may be concluded that the CO2 methanation over Fe/MSN catalysts depends on the Fe oxide species, catalysts structure of particle size and pore volume, and an appropriate amount of Fe species on the surface of MSN.