In Situ Fabrication of the Al2O3@NiMo Core–Shell Catalyst from LDH for Low-Pressure Hydrodeoxygenation of Fatty Acid Methyl Ester

The hydrothermal stability of supported metal catalysts is one of the greatest challenges in the development of biomass conversion to chemicals and fuels. Herein, a hydrotalcite-based core–shell catalyst (Al2O3@NiMo-LDO) was synthesized by urea precipitation and ion-exchange methods, which could selectively convert bio-oil model compounds to liquid alkanes with high activity and selectivity and excellent hydrothermal stability at low pressure. In the hydrogenation of methyl palmitate, the catalyst afforded 81% conversion and 99% selectivity of n-pentadecane and n-hexadecane under low pressure, with excellent hydrothermal stability. The excellent catalytic performance of Al2O3@NiMo-LDO was attributed to the strong hydrogen activation ability, improvement of the utilization of active components under low pressure, and the increase in the number of active Mo5+ species. The superior hydrothermal stability was attributed to the core–shell structure, which avoided the influence of the specific surface area of Al2O3 that is reduced by the hydration reaction between Al2O3 and H2O at high temperature.