Catalytic activity improvement of Ni3Al foils for methanol decomposition by oxidation–reduction pretreatment

A two-step pretreatment, oxidation in air followed by reduction in hydrogen, was performed on Ni3Al foils to improve the catalytic activity for methanol decomposition. A two-layer structure, Ni/Al2O3, was formed over the foil surface which was oxidized at 973 K and reduced, whereas a three-layer structure, Ni/NiAl2O4/Al2O3, was formed over the foil surface that was oxidized at 1173 K and reduced. In both cases the outmost Ni layer consisted of polycrystals and continuously covered the underlying oxides. Both pretreated foils exhibited lower onset temperature and enhanced catalytic activity for methanol decomposition into H2 and CO, compared to the untreated foil, and the difference between them was very small. In addition, they exhibited a good stability in catalytic performance at 673 K. The results demonstrate that the oxidation–reduction pretreatment effectively improves the catalytic performance of Ni3Al foil by the formation of an outmost Ni layer on the foil surface.

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► The Ni/Al2O3 layer formed over the Ni3Al foil reduced after oxidation at 973 K.
► The Ni/NiAl2O4/Al2O3 layer formed over the Ni3Al foil reduced after oxidation at 1173 K.
► Both pretreated foils exhibited considerably improved catalytic activity for methanol decomposition.
► High activity was attributed to the formation of the outmost Ni layer.