Influence of metal loading and reduction temperature on the performance of mesoporous NiO-MgO-SiO2 catalyst in propane steam reforming

In this research, a series of NiO-MgO-SiO2 catalyst samples with various nickel contents (5, 10, 15 and 20 wt %) were prepared by a co-precipitation method followed by a hydrothermal treatment and employed in propane steam reforming. The analyses revealed that the enhancement of the nickel content up to 15 wt % improved the propane conversion to 98.6% at 550 degrees C. Nonetheless, further increase in the nickel loading reduced the catalyst activity due to the formation of larger and more poorly dispersed active sites. Besides, 15 wt % nickel loading led to the high resistance against coke deposition with no detectable carbon on the catalyst surface. In addition, it was revealed that, the decrease in steam to carbon (S/C) ratio caused further carbon depositions upon the catalyst surface as well as producing higher extents of undesired by-products. Besides, results proved that the alternation of reduction temperature within 500-650 degrees C caused a significant influence on the dispersion and particle size of metallic Ni. The accessible metallic Ni for reactants and consequently catalyst performance was strongly affected by reduction temperature. The results exhibited that the reduced catalyst at 550 degrees C possessed the highest activity with the lowest amount of by-products owning to the formation of highly dispersed small Ni species. Higher reduction temperatures accelerated the agglomeration of Ni species, which negatively affected the catalytic performance. (C) 2021 Energy Institute. Published by Elsevier Ltd. All rights reserved.