A single-step synthesis route of square shaped wurtzite GaN nanotubes is reported by a quasi-vapor-solid process with detailed growth kinetics involving surface energies and Ga mobility along different crystalline facets. A wet chemical route is used for the functionalization of GaN nanotubes with Pt nanoclusters of average diameter similar to 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 H-2 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 H-2 at room temperature without any application of bias. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.