Metal-Modified Layered Double Hydroxide as Efficient Catalysts for the C–C Coupling of Furfural to Sustainable Aviation Fuel Precursors

High-energy-density sustainable aviation fuels are recognized as effective means to mitigate carbon emissions in the aviation sector. Here, we report various metal-modified layered double hydroxides (LDHs). The screened MgAlSn-LDH catalyst incorporating abundant oxygen vacancies and strong base sites yields (E)-1-(furan-2-yl)-5-methylhex-1-en-3-one (ALD) over 96% at 120 °C for 4 h. The catalyst exhibits promising long-term stability in a fixed-bed reactor at 170 °C. A combination of investigations using in situ DRIFTS studies and DFT calculations reveals that MgAlSn-LDH enhances the adsorption of methyl isobutyl ketone (MIBK) and furfural (FF). Further calculations have shown that the synergy of oxygen vacancies and strong base sites decreases the energy barrier of MIBK enolation, which increases the rate of the enolation reaction. This research provides a versatile synthesis method for improving the alkaline catalytic activity of LDH catalysts, and the performance of the catalysts can be extended to other upgrading processes of biomass chemicals.