The design and synthesis of a matrix nanocomposite containing amino carbon nanotubes used as a functionalized sensing layer for carbon dioxide detection by means acoustic wave sensing devices, e.g., SAW/BAW devices. These sensing materials contain a type of amino carbon nanotubes (single walled or multi-walled) and a polymer (or other compounds) which are sensitive to carbon dioxide in the acoustic wave sensing device based gas sensors. The sensitivity of the matrix consisting of the amino carbon nanotubes and a polymer (or other compounds) is ensured by the presence of amino groups which can react at room temperature with CO2 in a reversible process to form carbamates.