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The electronic structure of the tenfold surface of a decagonal Al-Ni-Co quasicrystal was investigated using metastable He * ͑2 3 S ,1s2s͒ deexcitation spectroscopy, which is extremely sensitive to the topmost surface. It was found that the density of states at the Fermi level was remarkably reduced at the topmost surface. The deexcitation of He * via a resonance transition followed by Auger neutralization observed on the quasicrystalline surface indicates the persistence of states within the pseudogap at the topmost surface. The similarity of the electronic structure between the topmost surface and the bulk is consistent with a bulk-terminated structure, as observed by low-energy ion scattering spectroscopy.

Ni3Al has attractive high temperature properties, such as high strength and good oxidation/corrosion resistance, and is possible to be used for high temperature chemical processing and manufacture. Until now, the catalytic properties of Ni3Al were rarely investigated since the leaching of aluminum from Ni3Al is difficult to obtain a porous Raney-Ni compared to NiAl3 and Ni2Al3. In the present work, the catalytic properties of Ni3Al were examined for hydrogen production reactions from methanol. It was found that alkali-leached Ni3Al showed high activity for methanol decomposition (CH3OH→ 2H2+CO). Furthermore, Ni3Al catalysts suppress the formation of methane, i.e. they show higher selectivity for the methanol decomposition reaction than Ni catalyst. These results indicate a possibility for Ni3Al used as a catalyst for hydrogen production reaction.

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