Ethylene glycol reduction method was used to prepare alumina supported Ru nanoparticles with different concentrations. All the synthesized materials were examined by different analytical techniques like XRD, TEM, EDX, H-2-chemisorption, XPS and H-2-TPD analysis. The performance of all the well synthesized Ru@Al2O3-x (x=2-10 Ru wt%) catalysts were tested for CO2 hydrogenation reaction with or without ionic liquid medium. The influence of the physiochemical properties of Ru@Al2O3-x (x=2-10 Ru wt%) catalysts was clearly observed during the catalysis CO2 hydrogenation reaction. The maximum catalytic activity was recorded with Ru@Al2O3-2 catalyst in [DAMI][CF3CF2CF2CF2SO3] ionic liquid. In this system, ionic liquid was noted as catalyst stabilizer and shifted the chemical equilibrium of CO2 hydrogenation reaction towards formic acid synthesis followed by the formation of intermediate carbonate. The Ru@Al2O3-2 catalyst in [DAMI][CF3CF2CF2CF2SO3] ionic liquid gave the best result in terms of formic acid synthesis and catalyst recycling (8 runs). [GRAPHICS] .