Hydrogen production by steam reforming of liquefied natural gas (LNG) over Ni–Al 2O 3 catalysts prepared by a sequential precipitation method: Effect of precipitation agent

Abstract

Mesoporous Ni–Al 2O 3 catalysts (denoted as NiAl–NH 4OH, NiAl–KOH, NiAl–NaOH, and NiAl–Na 2CO 3) were prepared by a sequential precipitation method using various basic solutions (NH 4OH, KOH, NaOH, and Na 2CO 3) as precipitation agents. They were then applied to the hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of precipitation agent on the physicochemical properties and catalytic activities of mesoporous Ni–Al 2O 3 catalysts in the steam reforming of LNG was investigated. Physicochemical properties of Ni–Al 2O 3 catalysts were strongly influenced by the precipitation agent. Surface area and pore volume of Ni–Al 2O 3 catalysts decreased in the order of NiAl–NH 4OH > NiAl–KOH > NiAl–NaOH > NiAl–Na 2CO 3. Regardless of the identity of precipitation agent, nickel species were finely dispersed on the surface of Ni–Al 2O 3 catalysts through the formation of surface nickel aluminate phase. LNG conversion and hydrogen composition in dry gas decreased in the order of NiAl–NH 4OH > NiAl–KOH > NiAl–NaOH > NiAl–Na 2CO 3. Nickel surface area played an important role in determining the catalytic performance of Ni–Al 2O 3 catalysts. Among the catalysts tested, NiAl–NH 4OH catalyst with the highest nickel surface area showed the best catalytic performance and the strongest resistance toward carbon deposition in the steam reforming of LNG.