Ni/Al-HAP Efficient Catalysis of Ethanol to Higher Alcohols

In this work, Al3+ was introduced into the hydroxyapatite lattice via co-precipitation-hydrothermal method, followed by impregnation to load metallic Ni, preparing a nickel-based aluminum-doped hydroxyapatite (Ni/Al-HAP) catalyst. Systematic characterization indicated that the incorporation of Al3+ effectively regulated the intensity and distribution of acidic and basic sites on the support surface and enhanced the dispersion of Ni species as well as the metal-support interaction, forming abundant Niδ+-O-Al active interfaces.

The reaction results show that the Ni/Al-HAP catalyst is activated under low-temperature conditions at 130 °C, and achieves high-efficiency ethanol conversion at 210 °C, with the conversion rate increasing to 26.3% and the total selectivity of C4+ higher alcohols remaining above 95%. Further optimization of solvents and other conditions achieved a single-pass ethanol conversion of 54.5%. Mechanistic studies revealed that the synergistic effect between the strong basic sites induced by Al3+ doping and the highly dispersed Niδ+ species not only efficiently catalyzed ethanol dehydrogenation to acetaldehyde but also greatly promoted the subsequent continuous aldol condensation reaction.