Hydrogen production by steam reforming of liquefied natural gas (LNG) over ordered mesoporous nickel–alumina catalyst

An ordered mesoporous nickel–alumina catalyst (denoted as OMNA) was prepared by a single-step evaporation-induced self-assembly method, and it was applied to the hydrogen production by steam reforming of liquefied natural gas (LNG). For comparison, a nickel catalyst supported on ordered mesoporous alumina support (denoted as Ni/OMA) was also prepared by an impregnation method. Although both Ni/OMA and OMNA catalysts retained unidimensionally ordered mesoporous structure, textural properties of the catalysts were significantly affected by the preparation method. Nickel species were finely dispersed in the OMNA catalyst as a form of surface nickel aluminate with a high degree of nickel-saturation. On the other hand, both bulk nickel oxide and surface nickel aluminate phases were formed in the network of Ni/OMA catalyst. Nickel species in the OMNA catalyst exhibited not only high reducibility but also strong resistance toward sintering during the reduction process, compared to those in the Ni/OMA catalyst. Both Ni/OMA and OMNA catalysts showed a stable catalytic performance without catalyst deactivation during the steam reforming of LNG due to the confinement effect derived from well-developed ordered mesoporous structure in the catalysts. However, OMNA catalyst with small crystallite size of metallic nickel exhibited higher LNG conversion and hydrogen yield than Ni/OMA catalyst. Furthermore, OMNA catalyst was more active in the steam reforming of LNG than non-ordered mesoporous nickel–alumina catalysts prepared by common surfactant-templating methods using cationic, anionic, and non-ionic surfactants.