Mesoporous nickel-alumina catalysts derived from MIL-53(Al) metal-organic framework: A new promising path for synthesizing CO2 methanation catalysts

A new synthesis route for the preparation of highly efficient and stable porous Ni-based alumina catalysts CO2 methanation is presented. It based on use MIL-53(Al), an Al-containing metal-organic framework (MOF) with high surface area, as sacrificial support. series Ni-Al2O3 powder samples Ni loadings ranging from 5 to 20 wt% was thus obtained. Their properties were thoroughly characterized by a set complementary techniques including N2-sorption, X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), adsorption, temperature programmed reduction (H2-TPR) transmission electron microscopy (TEM). After nickel impregnation thermal assisted organic ligands elimination, resulting materials appear interwoven nanosheets in which cations are intimately mixed forming NiAl2O4 spinel nanophases dispersed within amorphous alumina. This nanosheet morphology preserved after that leads Ni0-Al2O3 composed homogeneously Ni0 nanoparticles, even at highest content. As result, activity methanation, evaluated between 250–450 °C under atmospheric pressure, using constant gas hourly space velocity 68,900 h−1 molar reactant ratio H2/CO2 4, increased proportionally respect loading. On most active catalyst, selectivity CH4 always excellent (between 96 % 100 %) obtained yield (∼70 300 °C) about two times higher than commercial Al2O3 catalyst containing 25 Ni. The catalytic performances also better those already reported Ni/USY, Ni/SBA-15 well synthesized EISA one-pot procedure, tested same reaction conditions comparison. In this work utilization MIL-53(Al) starting material responsible peculiar improvement metallic dispersion due area MOF metal-support interaction likely existence remaining interface reduction. Sintering agglomeration (the main cause deactivation) therefore limited, boosting performance (activity, stability).