A wet chemical route is used for the functionalization of GaN nanotubes with Pt nanoclusters of average diameter ∼1.6 (0.4) nm in order to instigate the formation of localized Schottky barrier, responsible for carrier transport in the sensing process. Catalytically enhanced dissociation of molecular H₂ down to the lowest detection limit of 25 ppm at room temperature, as compared to those of reported GaN systems has been shown. We report, for the first time, a very low activation energy value of 29.4 meV which will be useful in practical sensing of H₂ at room temperature without any application of bias.