Hydrogen production by steam reforming of liquefied natural gas (LNG) over mesoporous nickel–alumina composite catalyst prepared by an anionic surfactant-templating method

Abstract

A mesoporous nickel–alumina composite catalyst (Ni–Al 2O 3) was prepared by an anionic surfactant-templating method, and was applied to hydrogen production by steam reforming of liquefied natural gas (LNG). For comparison, a nickel catalyst supported on mesoporous alumina (Ni/Al 2O 3) was prepared by an impregnation method. High surface area and well-developed mesopores of both Ni–Al 2O 3 and Ni/Al 2O 3 catalysts improved the dispersion of nickel species through the formation of nickel aluminate phase. In the Ni–Al 2O 3 catalyst, nickel species were homogeneously dispersed without significant pore blocking through the formation of Ni–O–Al composite structure. The Ni–Al 2O 3 catalyst was very efficient for suppressing the nickel sintering during the reduction process, resulting in enhanced nickel dispersion and active nickel surface area. Ni–Al 2O 3 catalyst showed a stable catalytic performance without significant catalyst deactivation during the reaction extending over 3000 min, while Ni/Al 2O 3 catalyst exhibited a stable catalytic performance at the initial stage but experienced a slight catalyst deactivation in the long run. The Ni–Al 2O 3 catalyst showed a better catalytic performance than the Ni/Al 2O 3 catalyst. High active nickel surface area and fine nickel dispersion of Ni–Al 2O 3 catalyst played an important role in enhancing the dehydrogenation reaction of hydrocarbon species and the gasification reaction of adsorbed carbon species in the steam reforming of LNG. Strong resistance of Ni–Al 2O 3 catalyst toward carbon deposition and nickel sintering was also responsible for its high catalytic performance.