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Pd/C-[BMIm][BF 4 ] catalyst displayed high activity for acceptorless dehydrogenation of biomass-derived alcohols to produce aromatic ketones under mild conditions without any acid/base additives, and this catalyst could be recovered and reused for 5 runs without obvious activity loss. This work provides a potential approach for the effective utilization of renewable biomass resources to produce aromatic compounds and clean H 2. [Display omitted] • The combination of Pd/C with specific ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF 4 ]) displayed high activity for the dehydrogenation of aromatic alcohols to produce aromatic ketones. • The Pd/C-[BMIm][BF 4 ] pair promoted the dehydrogenation of aromatic alcohols and inhabited the hydrogenation of aromatic alcohols. • The catalyst could be recycled for 5 runs without obvious loss of activity. • Pd/C could be anchored and stabilized by the IL through interacting with [BMIm]+ cation, and both the [BMIm]+ cation and the [BF 4 ]- anion play vital roles in activating hydroxyl-H and hydroxyl α-H of the aromatic alcohol. Acceptorless dehydrogenation of alcohols is a promising pathway for biomass resource utilization and hydrogen supply, but still lacking for simple and effective catalysts. Herein, we report a metal-ionic liquids (ILs) catalyst for synergistical catalytic dehydrogenation of aromatic alcohols to aromatic ketones under mild conditions without any acid/base additives. It is found that the combination of Pd/C with 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF 4 ]) displays high activity for the dehydrogenation of biomass-derived alcohols including 1-phenyl-1-ethanol, 1-phenyl-1-propanol and 1-(4-methoxyphenyl)ethanol. Mechanistic studies reveal that the Pd/C can be anchored and stabilized by the IL via interacting with [BMIm]+ cation, and the [BF 4 ]- anion plays vital role in the activation of hydroxyl-H and α-H protons via hydrogen bonding interactions. These interactions create an effective microenvironmental for Pd/C catalyzing the cleavage of the hydroxyl-H and α-C H bonds of α-hydroxyl aromatic alcohols to generate aromatic ketones and H 2. Moreover, the Pd/C-[BMIm][BF 4 ] catalyst could be recovered and reused for 5 runs without obvious activity loss. This strategy provides more evidences for the synergetic catalysis of metal and ionic liquids and exhibits potential application prospects for hydrogen supply from renewable biomass-derived alcohols. [ABSTRACT FROM AUTHOR]