Catalytic behaviour of NiAl<inf>2</inf>O<inf>4</inf> spinel upon hydrogen treatment

The effect of reduction on the catalytic activity and selectivity of nickel aluminate spinel has been reported using the 2-propanol decomposition reaction. The unreduced catalyst showed only dehydration activity. When reduced in hydrogen at different temperatures starting from 200 °C, dehydrogenation activity was observed. After reduction at 450 °C, the activity completely transformed into dehydrogenation, while the spinel structure remained unchanged. The unreduced and reduced catalysts were characterized by X-ray diffraction, temperature-programmed reduction, diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The mechanism for the decomposition is discussed in terms of the coordination of aluminium ion and reducibility of nickel. © 1993 Chapman & Hall.