A gas expanded liquid (GXL) is a liquid that has its volume raised as a result of been pressurized with a gas with the ability to condense [1].Several reports on the applications of GXL systems have been reported and interests in them continue to grow [2].Consequently, they have been used in variety of engineering processes including the synthesis of nanoparticles due to their pressure-tunable properties [3].The properties of the solvents/mixture of solvents at the expanded liquid conditions are essentially and considerably different from those at atmospheric pressure due to the fact that the mixture of solvent is replaced considerably up to about 80 % volume by CO2.The method offers simple and direct synthesis of micro-and nano-sized particles with narrower size distributions.Carbon dioxide expanded liquids (CXLs) are the most popularly utilized group among the GXLs.The addition of a miscible compressible gas (CO2) to an organic solvent-water mixture causes the expansion in volume of the liquid phase as a result of the increase in the mole fraction of CO2, providing endless potential for tuning, adjusting and enhancing system properties [4].In this system, only the liquid phase contacts the reactant;consequently, as expansion degree, the liquid mothers reaction media that facilitate the formation of nanoparticles as a result of enhanced reaction kinetics [5].Despite these attributes, the technique seems have not been applied to the synthesis of the valuable Al2O3 catalyst in literature;there are some reports about the use of ethanol-water system to produce Al2O3 however, not by the said technique.Herein, we applied the technique for the direct synthesis of high surface area (519.8m2/g) and pore volume (1.08cm3/g) Al2O3 nanoparticles without the use of any structure directing substances or templates.The phase identification was obtained by XRD analysis with Xpert highscore plus and the morphology was studied with SEM;revealing a honey-comb-like network of nanoparticles.