Hydrogen production by steam reforming of simulated liquefied natural gas (LNG) over mesoporous nickel–M–alumina (M = Ni, Ce, La, Y, Cs, Fe, Co, and Mg) aerogel catalysts

Mesoporous nickel–M–alumina aerogel catalysts (denoted as NiMAE) with different second metal (M = Ni, Ce, La, Y, Cs, Fe, Co, and Mg) were prepared by a single-step sol–gel method and a subsequent CO2 supercritical drying method. The effect of second metal of mesoporous nickel–M–alumina aerogel catalysts on their physicochemical properties and catalytic activity for steam reforming of simulated liquefied natural gas (LNG) was investigated. Textural and chemical properties of NiMAE catalysts were strongly influenced by the identity of second metal. Nickel species were highly dispersed on the surface of NiMAE catalysts through the formation of nickel aluminate phase. In the steam reforming of LNG, both LNG conversion and hydrogen yield decreased in the order of NiLaAE > NiCeAE > NiYAE > NiCsAE > NiNiAE > NiFeAE > NiCoAE > NiMgAE. Average nickel diameter of NiMAE catalysts was well correlated with LNG conversion and hydrogen yield over the catalysts. Among the catalysts tested, NiLaAE catalyst exhibited the best catalytic performance due to its smallest average nickel diameter. Furthermore, NiLaAE catalyst exhibited a strong capability of facilitating heat and mass transfer of reactant and product during the steam reforming of LNG. Water–gas shift reaction governed the steam reforming reaction over NiLaAE catalyst under the steam-rich reaction condition (steam/carbon > 2).

Research highlights
► Hydrogen was produced by steam reforming of simulated liquefied natural gas.
► Mesoporous nickel–metal–alumina aerogel catalysts were used.
► Hydrogen yield increased with decreasing average nickel diameter.
► La was found to be the most efficient second metal.