Hydrogen production by steam reforming of liquefied natural gas (LNG) over mesoporous Ni-Al2O3 aerogel catalyst prepared by a single-step epoxide-driven sol-gel method

A mesoporous Ni-Al2O3 aerogel catalyst was prepared by a single-step epoxide-driven sol-gel method and a subsequent supercritical CO2 drying method (NA-ES catalyst). For comparison, a mesoporous Ni-Al2O3 aerogel catalyst was also prepared by a single-step alkoxide-based sol-gel method and a subsequent supercritical CO2 drying method (NA-AS catalyst). Differences in physicochemical properties and catalytic activities of mesoporous Ni-Al2O3 aerogel catalysts in the steam reforming of liquefied natural gas (LNG) were investigated. Textural properties of Ni-Al2O3 aerogel catalysts were affected by the preparation method. Nickel species were highly dispersed in alumina through the formation of nickel aluminate phase in both NA-ES and NA-AS catalysts. However, chemical states of Al atoms in both catalysts were quite different. In addition, nickel species in the NA-ES catalyst exhibited high reducibility and high dispersion compared to those in the NA-AS catalyst. In the steam reforming of LNG, NA-ES catalyst exhibited a better catalytic performance than NA-AS catalyst in terms of LNG conversion and hydrogen yield, although both catalysts showed a stable catalytic performance during the reaction without deactivation behavior. Furthermore, NA-ES catalyst with small average nickel diameter suppressed water-gas shift reaction. Reducibility and dispersion of nickel species served as important factors determining the catalytic performance of the catalysts.