Preparation of a Novel NiAlO Composite Oxide Catalyst for the Dehydrogenation of Methylcyclohexane

Abstract

A series of NiAlO composite oxide catalysts with high surface areas and high Ni dispersion were prepared through an improved co-precipitation method. The new preparation method effectively improved the specific surface area and pore volume of the catalyst, promoted the dispersion of nickel species, alleviated the agglomeration of the catalyst, and improved the stability of the catalyst by strengthening the interaction between Ni and Al. The typical catalyst Ni20Al had a specific surface area of 359 m2/g and a NiAl2O4 phase. In the dehydrogenation of methylcyclohexane over the Ni20Al catalyst, the conversion of methylcyclohexane could reach 77.4%, with toluene selectivity of 85.6%, and a hydrogen release rate of 63.94 mmol g−1 h−1, and did not show any significant inactivation during the stability test over 29 h under the reaction conditions of reaction temperature 450 °C and LHSV = 4 mL g−1 h−1. However, the conversion of methylcyclohexane with the IM-NiAl catalyst prepared through the traditional impregnation method was only 50.75%, with toluene selectivity of 70.5%, and with a hydrogen release rate of 35.84 mmol g−1 h−1, and the lifetime of the catalyst was only 15 h.