A dechlorination pathway for synthesis of horn shaped carbon nanotubes and its adsorption properties for CO2, CH4, CO and N2

► Horn shaped carbon nanotubes have been synthesized using dechlorination pathway. ► Adsorption isotherm of CO2, CO, CH4 and N2 were obtained at different temperatures. ► High CO2 and CO adsorption capacity with better selectivity over N2 was achieved. ► It provides new adsorbent material for the separation and recovery of gases.