The synthesis of horn-shaped carbon nanotubes using carbon tetrachloride as carbon source was carried out by solvothermal method at 200 degrees C for 2h. The scanning and transmission electron microscopic characterization of the obtained product showed the formation of horn-shaped carbon nanotubes with irregular wall structure having inner diameter of similar to 105nm and length of similar to 1 mu m. The equilibrium gas adsorption properties of horn-shaped carbon nanotubes derived from carbon tetrachloride were successfully investigated for CO2, CH4, and N-2 at 288, 303, and 318K. Horn-shaped carbon nanotubes possess better CO2 adsorption capacity (2.53mmol/g) with high capacity selectivity (14.7) and equilibrium selectivity (59.1) over N-2 at 288K. The detailed adsorption study with estimation of physical parameters such as Henry's constant and heat of adsorption identifies the horn-shaped carbon nanotubes as a potential adsorbent material in the field of CO2 storage and separation.